mini-therm iitm

MINI-THERMLAARS

H00

7140

0Y

FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician,qualified in hot water boiler installation and maintenance. Improper installation and/or operation couldcreate carbon monoxide gas in flue gases which could cause serious injury, property damage, or death.Improper installation and/or operation will void the warranty.

Installation and Operation Instructions Document 1025Y

WARNINGIf the information in this manual is notfollowed exactly, a fire or explosion mayresult causing property damage, personalinjury or loss of life.

Do not store or use gasoline or otherflammable vapors and liquids in the vicinityof this or any other appliance.

WHAT TO DO IF YOU SMELL GAS• Do not try to light any appliance.• Do not touch any electrical switch; do not

use any phone in your building.• Immediately call your gas supplier from a

nearby phone. Follow the gas supplier'sinstructions.

• If you cannot reach your gas supplier, callthe fire department.

Installation and service must be performed bya qualified installer, service agency, or gassupplier.

AVERTISSEMENTAssurez-vous de bien suivres les instructionsdonnées dans cette notice pour réduire auminimum le risque d’incendie ou d’explosion oupour éviter tout dommage matériel, touteblessure ou la mort.

Ne pas entreposer ni utiliser d’essence nid’autres vapeurs ou liquides inflammables dansle voisinage de cet appareil ou de tout autreappareil.QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:

• Ne pas tenter d’allumer d’appareils.• Ne touchez à aucun interrupteur. Ne pas vous

servir des téléphones dansle bâtiment où vousvous trouvez.

• Appelez immédiatement votre fournisseur degaz depuis un voisin. Suivez les instructionsdu fournisseur.

• Si vous ne pouvez rejoindre le fournisseur degaz, appelez le sservice des incendies.

L’installation et l’entretien doivent être assurés parun installateur ou un service d’entretien qualifié oupar le fournisseur de gaz.

Installation and OperationInstructions for

Mini-Therm IITM

ResidentialGas-FiredHydronic BoilersModels JVS, JVTSizes 50-225U.S. Patent No. 1,609,692Canada Patent No. 383,318

Vent damper is optional in some provinces of Canada.These instructions are to be stored in the packet

provided on the boiler.

A subsidiary of BRADFORD WHITE

LAARS Heating Systems

TABLE OF CONTENTS

SECTION 1.General Information1.1 Introduction ................................................... 31.2 Warranty ....................................................... 31.3 Codes and Standards ................................... 31.4 Technical Assistance .................................... 31.5 Materials Installer Must Provide ................... 31.5.1 Materials for All Installations ......................... 31.5.2 Materials for Most Installations ..................... 31.5.3 Diagnostic Tools ........................................... 41.6 Specifications ............................................... 41.6.1 General Specifications ................................. 41.6.2 Dimensions ................................................... 4

SECTION 2.Installation Instructions2.1 Introduction ................................................... 42.2 Field Assembly ............................................. 52.3.1 Clearances ................................................... 62.3.2 Flooring ........................................................ 6

SECTION 3.Venting3.1 Combustion Air Supply ................................. 73.2 Exhaust Venting ........................................... 73.3 Vent Pipe Sizing and General

Installation .................................................... 83.4 Common Venting Systems ........................... 83.4.1 Venting Multiple Appliances ......................... 83.4.2 Inspection of Commonly Vented

Appliances .................................................... 9

SECTION 4.Gas Connections4.1 Gas Supply and Piping ............................... 104.2 Special Precautions for LP Gas.................. 11

SECTION 5.Water Connections5.1 Water Piping ............................................... 125.1.1 By-pass Piping ........................................... 125.2 Alternate Auto-Bypass Operation ............... 125.3 Flow Requirements .................................... 155.4 Chilled Water Systems ............................... 165.5 Oxygen Permeable Systems ...................... 165.6 Anti-Freeze ................................................. 16

SECTION 6.Electrical6.1 General Information .................................... 166.2 Main Power ................................................ 166.3 Grounding................................................... 216.4 Auxiliary Devices ........................................ 216.4.1 Flow Switch ................................................ 216.4.2 Heat Anticipator .......................................... 21

SECTION 7.Operating Instructions7.1 Normal Operation ....................................... 217.2 Start-up ....................................................... 227.2.1 Filling the System ....................................... 227.2.2 Boiler Start-up ............................................ 227.3 Lighting and Shutdown Procedures ........... 237.3.1 Lighting the Boiler ....................................... 237.3.2 Shutdown ................................................... 247.3.2.1 Main Burner Shutdown (JVT Only) ............. 247.3.2.2 Complete Shutdown ................................... 247.4 High Altitude Burner

Air Shutter Adjustment................................ 24

SECTION 8.Maintenance8.1 General Maintenance ................................. 258.2 Boiler Components and Their

Operation .................................................... 26

SECTION 9.Troubleshooting9.1 General Boiler Troubleshooting .................. 279.2 Troubleshooting Guide ............................... 289.3 Troubleshooting Honeywell S8600

Intermittent Pilot System............................. 299.4 Electrical Troubleshooting .......................... 30

SECTION 10.Glossary10.1 Glossary of Terms ...................................... 30

SECTION 11.Replacement Parts11.1 Ordering Information .................................. 3111.2 Parts List .................................................... 3111.3 Exploded View ............................................ 34

Mini-Therm II Hydronic Boiler

SECTION 1.General Information

1.1 IntroductionThis manual provides information necessary for

the installation, operation, and maintenance of LaarsModel JV copper tube hydronic boilers.

All application and installation proceduresshould be reviewed completely before proceeding withthe installation. Consult the Laars factory, or localfactory representative, with any problems or questionsregarding this equipment. Experience has shown thatmost operating problems are caused by improperinstallation.

These boilers are available in two configurations;the JVT has a thermocouple/continuous burning pilot,and the JVS has an electronic intermittent ignitiondevice (I.I.D.). Look for the model designation on therating plate, which can be found on top of the boiler inthe right rear corner. If the unit is part of a Mini-Combo II (model MC) Residential Gas-Fired Space/Water Heater, refer also to Document 8001, Mini-Combo II Installation and Operation Instructions.

The Laars automatic vent dampers are standardon all U.S. and Canadian models. The Laars side wallpower venters can be used on both JVS and JVTmodels. Special instructions for their installation areincluded in the vent damper and power venterpackage. Read them carefully before installation.

1.2 WarrantyThe Laars Model JV boilers are covered by a

limited warranty. The owner should fill out thewarranty registration card and return it to Laars.

All warranty claims must be made to anauthorized Laars representative or directly to thefactory. Claims must include the boiler serial numberand model (this information can be found on therating plate), installation date, and name of theinstaller. Shipping costs are not included in thewarranty coverage.

Some accessory items are shipped in separatepackages. Verify receipt of all packages listed on thepacking slip. Inspect everything for damageimmediately upon delivery, and advise the carrier ofany shortages or damage. Any such claims should befiled with the carrier. The carrier, not the shipper, isresponsible for shortages and damage to the shipmentwhether visible or concealed.

The warranty does not cover damage caused byimproper assembly installation, operation or fieldmodification.

1.3 Codes and StandardsThe JV Hydronic Boiler (or Mini-Therm II) is

design certified by CSA (Canadian StandardsAssociation) as complying with the latest edition of

the “Standard for Gas Fired Low Pressure Steam andHot Water Boilers”, ANSI Z21.13 in the USA andCAN1-4.9 in Canada.

All Laars boilers must be installed in accordancewith the local building and installation codes as perthe utility or authorities having jurisdiction. All localcodes take precedence over national codes.

In the absence of local codes, refer to thefollowing national codes for installation:1. In the United States, the latest edition of "The

National Fuel and Gas Code", ANSI Z223.1.Specifically, refer to Chapter 10, "Venting ofEquipment".

2. In Canada, the latest edition of "The InstallationCodes for Gas Burning appliances andEquipment", CSA B149.1.Any changes to the boiler, gas controls, gas

orifices, wiring, draft diverter, or improper installationmay void the warranty. If change is required to any ofthe above, consult the factory.

1.4 Technical AssistanceConsult Laars Heating Systems or your local

Laars factory representative with any questions orproblems involving the specifications, installation, andoperation of your Laars equipment. An experiencedtechnical support staff is ready to assist you inassuring the proper performance and application ofLaars products. For technical support call the LaarsHeating Systems Technical Service Department.

1.5 Materials Installer Must Provide1.5.1 Materials for All InstallationsThe following items are needed and are to be

supplied by the installer for all Mini-Therm II boilerinstallations:1. The correct size gas pipe to supply the gas to the

boiler (see Section 4.1 for correct gas pipe size).2. A CSA listed manually operated gas valve to be

installed in the gas line outside of the boilerjacket.

3. A suitable gas union joint or other removableconnector to connect the boiler to the gas lineoutside of the boiler.

4. Plumbing items needed to provide a sedimenttrap (drip leg) in the gas line between the manualgas valve and the union to the boiler.

5. A 115 VAC power supply. A junction box is notneeded at the boiler, connections are made insideof the boiler’s control panel (see Figure 8).

6. Vent pipe of the same or larger diameter as thevent damper or draft diverter outlet (see Section3.3 for venting instructions).1.5.2 Materials for Most InstallationsIn addition to the items listed above, the

following items may be needed:


1. Plumbing materials for the bypass piping, whichis required for:a. Any system where the return water

temperature may be less than 120°F, suchas in-floor radiant systems, snow meltsystems or other systems where a “coldstart” is expected frequently due tothermostat setbacks, etc. See Figure 11.

b. Any system where the temperature riseacross the heat exchanger is above 30°F(see Section 5 and Figure 7).

2. Combustion air grates for openings sized inaccordance with Section 3.1.

3. Field interlock wiring for any motorizedcombustion air louvers to ensure the boiler doesnot fire if motorized louvers do not open.

4. A suitable non-combustible base if installed on acombustible floor (see Section 2.3.2)1.5.3 Diagnostic ToolsThe following materials are needed to verify

correct installation:1. Gas manometer to verify gas pressure2. Strap-on, digital or infrared thermometer to

check temperature rise across the heat exchanger.3. Suggested: Draft gauge and combustion test

equipment.

1.6 Specifications1.6.1 General Specifications

1. Installation Location:Certified for use in Indoor Applications only

2. Minimum Clearance From CombustibleMaterial:See Table 1 in Section 2.3.1.

3. Supply Gas Type:Certified for use with Natural Gas and LP Gas

4. Gas Pipe/Boiler Gas Valve Connection:Nat LP

50-225 ½" NPT ½" NPT5. Inlet Gas Supply Pressure:

Minimum MaximumNatural Gas: 5.5" WC 10.5" WCLP Gas: 10.0" WC 13.0" WC

6. Water Pipe/Boiler Connection:1 ¼" NPT

7. Water Flow Rate:See Table in Section 5.2

8. Pressure Relief Valve:30 PSI

9. Recommended system pressure:12 PSI

10. Exhaust Vent Connection Size:50 4" Diameter75-100 5" Diameter125-160 6" Diameter225 7" Diameter

11. Electrical Supply:115 Volts AC

12. Modification of Boiler for High Altitude:Mini-Therm II Boilers are normally shippedfrom the factory in the low altitude (sea level)operational configuration. When requested, theboilers can be configured and shipped for higheraltitudes. For field conversions to change altitudeconfigurations, conversion parts are availablefrom Laars. For more information or call theCustomer Service Department.

1.6.2 DimensionsSee Figure 1 for a diagram showing the boiler’s

exterior dimensions and dimensions to criticalconnections on the boiler.

SECTION 2.Installation Instructions

2.1 Introduction

WARNINGImproper installation or maintenance can causenausea or asphyxiation from carbon monoxide influe gases which could result in severe injury, ordeath.

AVERTISSEMENTUne installation ou un entretien in adéquat peutcauser la nausée ou l’asphyxie en raison dumonoxyde de carbone présent dans les gaz decombustion et même entrainer des blessuresgraves ou la mort.

Install the Mini-Therm II boilers and ventdampers in accordance with the procedures in thismanual, local codes and ordinances, and in accordancewith the latest edition of the appropriate national code(see Section 1.3 “Codes and Standards”).

All gas-fired products require correct installationto assure safe operation. The requirements for boilersinclude the following:1. Field assembly2. Appropriate site location (clearances) and

flooring3. Sufficient combustion and ventilation air4. Properly sized gas meter and piping5. Proper electrical wiring (if required)6. Adequate water flow

This manual provides the information needed tomeet these requirements. Review all application andinstallation procedures completely before continuingthe installation.NOTE: The Mini-Therm II boiler is approved for indoorinstallation only.


2.2 Field Assembly1. Mini-Therm II boilers have built-in draft diverter

for natural draft operation.2. Find the vent damper box which is located in the

boiler package.3. Install the vent damper directly to the top of the

draft diverter outlet with the damper operatorfacing to the front of the boiler, and with theflow direction arrow pointing upward. Use thevent damper wire harness provided with theboiler to connect the vent damper to the boiler.The bracket end of the harness should beconnected to the vent damper actuator.

4. For Model JVS only: Install the metal plugprovided with the vent damper onto the damperplate hole. Disregard the metal plug in case ofstanding (continuous) pilot boilers. For all JVTmodels, the damper plate hole should never beblocked.

5. Do not modify the automatic vent damperdevice. It is very important that no other ventsare closed. Provide at least six inches clearancebetween the automatic vent damper andcombustible construction, and be sure to allowaccess for servicing the damper.

6. Install the temperature/pressure gauge providedin the parts box.

Figure 1. Dimensional Information.

Vent Damperoptional in Canada

FrontView

TopView

LeftSideView

B D

V

E

9-1/424

718

17-3/4 451

Vent DamperHarness

1-1/4 NPT

DraftDiverter A/2

C

A

In Return

T&P Gauge

Out Supply

PRV

Dimensions in inches cm

Dimensions Water Gasinches cm Conn. Conn.

Size* A B C D E V in. in.50 13-3/8 34 27-3/4 71 23-5/8 60 21-3/4 55 26-1/2 67 4 10 1-1/4 1/275 13-3/8 34 27-3/4 71 24-1/8 61 21-3/4 55 27-1/2 70 5 13 1-1/4 1/2

100 16-7/8 43 28-3/4 73 24-1/8 61 22-3/4 58 27-1/2 70 5 13 1-1/4 1/2125 16-7/8 43 28-3/4 73 23-5/8 60 22-3/4 58 27-1/2 70 6 15 1-1/4 1/2160 20-3/8 52 28-3/4 73 23-5/8 60 22-3/4 58 27-1/2 70 6 15 1-1/4 1/2225 25-5/8 65 31-1/2 80 23-1/4 59 23-3/4 63 27-1/2 70 7 18 1-1/4 *3/4*** Values shown are for both JVS and JVT Models **1/2 for propane

Figure 2. Field Assembly Items.

VentDamperHarness

VentDamper

DraftDiverter(built-in)

TempPressGauge


CautionDo not force motor operation when operator isfastened to the damper by moving the damperblade, turning the shaft or by turning the positionindicator.

AttentionNe pas tourner le registre manuellement avec ousans courant électrique ou le moteur seraendommagé.

2.3.1 ClearancesThe boiler must be placed to provide clearances

on all sides for maintenance and inspection. Theremust also be minimum distances maintained fromcombustible surfaces (see Table 1).

2.3.2 FlooringThe boiler shall be installed on a level floor of

noncombustible construction or on fire-resistant slabsor arches. Noncombustible flooring is defined asflooring material and surface finish not capable ofbeing ignited and burning and with no combustiblematerials against the underside. Acceptable materialsare those consisting entirely of a combination of steel,iron, brick, tile, concrete, slate, glass or plaster. Donot install the heater directly on a combustible woodor carpet floor without placing a noncombustibleplatform between the floor and the heater.

The boiler can be installed on a combustiblefloor if a noncombustible base assembly, availablefrom Laars, is used. See the boiler rating plate or theParts List (Section 11) of this manual for theappropriate base part number. Boilers must never beinstalled directly on carpeting.

As an alternative to the Laars noncombustiblebase plate, in the United States, the National Fuel GasCode allows a heater to be placed on a combustiblesurface when there is a platform under the heater madeof hollow masonry no less than 4 inches (102millimeters [mm]) thick, covered with sheet metal atleast 24 gauge thick and extending beyond the fullwidth and depth of the heater by at least 12 inches(305mm) in all directions. The masonry must be laidwith ends unsealed, and joints matched to provide freecirculation of air from side to side through themasonry (see Figure 4). If the boiler is installed in acarpeted alcove, the entire floor of the alcove must becovered by a noncombustible platform.

Note: Clearances listed in Table 1 are manufacturer’s testedvalues. These are given as minimum values. Where local andnational codes apply, and values are different than those listed inTable 1, use the greater value to ensure safe operation.

Table 1. Minimum Boiler ClearancesFrom Combustible Surfaces.

Dégagements Minimaux à Assurer Entre Ics Parois deL’appareil et leo Constructions Combustibles

Boiler Sizes 50-125 160-225Clearances in cm in cmLeft side 6 15 6 15Right side 6 15 6 15Rear 6 15 6 15Front 4 10 6 15Flue 6 15 6 15Top 23 48 36 91

At least 15" (381mm) access must be available infront of the boiler for burner removal. Consult localcodes for clearances to hot water pipes andaccessories.

If the boiler is to be installed in a garage, allburners and burner ignition devices must have aminimum 18" (457mm) clearance above the floor.

The Model JV-50 through JV-100 boilers can beinstalled in a closet, as long as the minimumclearances shown in Table 1 and Figure 3 areobserved. Special attention should be paid toclearances between the front of the boiler and thecloset door when it is closed.

Consult the American National Standard Z21.13for more information concerning closet installations.In Canada, refer to the latest edition of CSA-B149.1.

Figure 3. Closet and Alcove Installation (see Table 3).

Dimensions in inches cm.

6 15

6 15

6 154*10

*6" for models JV160 to JV225.

Sheet Metal Cover Min. Thickness 24 Gauge Galvanized

Hollow Concrete Block

12" Min.

Figure 4. Typical Combustible Floor Installation.

Sheet Metal CoverMin. Thickness 24Gauge Galvanized

HollowConcreteBlock

12" Min.(305mm)


SECTION 3.Venting

3.1 Combustion Air SupplyThe boiler location must provide sufficient

air supply for proper combustion, and ventilationof the surrounding area as outlined in the latestedition of ANSI standard Z223.1 or in Canada,CSA-B149.1, and any local codes that may beapplicable.

In general, these requirements specify that boilerrooms which represent confined spaces should beprovided with two permanent air supply openings; onewithin 12 inches (305mm) of the ceiling, the otherwithin 12 inches (305mm) of the floor (see Table 2).

Inside Air Supply: When combustion issupplied from inside the building, each openingshould have a minimum free area of one square inchper 1,000 BTU/h (0.3kW) input of the total inputrating of all appliances in the enclosed area. Theseopenings should never be less than 100 square inches(645 sq. cm).Note: In Canada, follow Canadian Standard, CSA-B149.1 or local codes.

Exhaust Fans or Vents: Any equipment whichexhausts air from the boiler room can deplete thecombustion air supply or reverse the natural draftaction of the venting system. This could cause flueproducts to accumulate in the boiler room. Additionalair must be supplied to compensate for such exhaust.

The information in Table 2 is not applicable ininstallations where exhaust fans or blowers of anytype are used. Such installations must be designed byqualified engineers.

If a blower or fan is used to supply air to theboiler room, the installer should make sure it does notcreate drafts which could cause nuisance shutdowns ofthe pilot. If a blower is necessary to provide adequatecombustion air to the boiler, a suitable switch orequivalent must be wired into the boiler control circuitto prevent the boiler from firing unless the blower isoperating.

The boiler must be completely isolated andprotected from any source of corrosive chemicalfumes such as those emitted by trichlorethylene,perchlorethylene, chlorine, etc.

WARNINGDo not store any chemical, cleaners, or othercorrosive material near combustion air openings orin the room. Avoid locating dryer vents in the vicinityof combustion air openings. Failure to preventcorrosive materials from mixing with combustion aircan result in reduced boiler life and unsafe boileroperation.

AVERTISSEMENTN’entrepposer aucun produit chimique, produitnettoyant ou produit corrosif à proximité desbouches d’air de combustion ou dans la pièce.Éviter de placer des tuyaux de ventilation poursécheuse à proximité des bouches d’air decombustion. Le fait de laisser des maitièrescorrosives se mélanger à l’air de combustion risquede réduire le cycle de vie de l’appareil de chauffageet de compromettre son fonctionnement.

3.2 Exhaust VentingVent piping must be of the same or larger

diameter as the vent damper or draft diverter outlet.The only correct procedure for vent pipe sizing is todo so in accordance with Table 3 and the applicableinstallation code as stated in the following warning.

Boiler Size Outside AirArea in Sq. In.*

Inside AirArea in Sq. In.* (sq cm)

50 15 97 100 645

75 20 129 100 645

100 25 161 100 645

125 32 206 125 807

160 40 258 160 1032

225 60 387 225 1452*Area indicated is for one of two openings; one at floor level andone at the ceiling, so the total net free area would be double thefigures indicated. For special conditions, refer to NFPA54 ANSIZ223.1. In Canada refer to the National Standard CSA B149.1which differs from this table.NOTE: Check with louver manufacturers for Net Free Area oflouvers. Correct for screen resistance to the Net Free Area if ascreen is installed. Check all local codes applicable tocombustion air.

Table 2. Minimum RecommendedAir Supply to Boiler Room.

Outside Air Area*Sq. In. sq cm

Inside Air Area*Sq. In. sq cm

Important: See gas piping selection chart, Table 3 forgas line sizing. In all cases, pipe size is larger thaninlet connection on heater. Run pipe size shown inchart and reduce at heater inlet.

Outside Air Supply: When combustion air issupplied directly through an outside wall, each openingshould have a minimum free area of one square inch per4,000 BTU/h (1.2kW) input of the total input rating ofall appliances in the enclosed area.

If air is provided through horizontal ducts,each opening and duct must provide one square inchof flow area for each 2000 BTU/h (0.6 kW). Theserequirements are summarized in Table 2. Note thatthe required size of openings shall be based on thenet free area of each opening. Where the free areaof louver or grille is known it shall be used incalculating the effective free area. Where the freearea are not known, it shall be assumed that woodlouvers will have 25 percent free area, and metallouvers and grilles will have 75 percent free area.


WARNINGVent pipe diameter must be as required by theNational fuel Gas Code Z223.1 or the CanadianInstallation Codes for Gas Appliances CSA-B149.1.Undersize pipe can result in inadequate ventingand oversize pipe can result in vent condensation.In either case the result can be release ofcombustion products to the indoors. This can causeserious injury or death by carbon monoxidepoisoning or asphyxiation.

AVERTISSEMENTLe diamètre des tuyaux de ventilation doit répondreaux exigences du National Fuel Gas Code Z223.1ou du code canadien des installations des appareilsà gaz CSA B149.1. Des tuyaux trop petits rispquentd’entraîner une ventilation inadéquate et des tuyauxtrop gros risquent de provoquer une condensationdans les tuyaux. Dans un cas comme dans l’autre,des produits de combustion risquent de s’échapperdans le bâtiment et causer des blessures graves oul’asphyxie par le monoxyde de carbone.

Do not weld or fasten the vent pipe to the boilerdraft diverter. The weight of the stack must not rest onthe boiler. The draft diverter and boiler top must beeasily removable for normal boiler service andinspection.

Avoid horizontal runs of the vent pipe, and 90°elbows, reductions and restrictions. Horizontal runsshould have at least a 1/4" rise per foot (20mm permeter) in the direction of flow. A vent connector shallbe supported for the design and weight of the materialemployed to maintain clearances and prevent physicaldamage and separation of joints.

Avoid terminating boiler vents near airconditioning or air supply fans. The fans can pick upexhaust flue products from the boiler and return theminside the building, creating a possible health hazard.Do not located the vent terminal where flue productscould strike against building materials and causedegradation.

Always use double-wall or insulated vent pipewhen used as a chimney (Type B or equivalent). Incold weather, uninsulated outside vents can chill therising flue products, blocking the natural draft actionof the venting system. This can create a health hazardby spilling flue products into the boiler room. Useengineered venting tables acceptable to the authorityhaving jurisdiction to size the venting pipe or liner.

Avoid oversize vent piping or extremely longruns of the pipe which may cause excessive coolingand condensation.

Before connecting a vent connector to achimney, the chimney passageway shall be examinedto ascertain that it is clear and free of obstructions.When inspection reveals that an existing chimney isnot safe for the intended application, it shall be rebuiltto conform to nationally recognized standards (seeNational Building Code or ANSI/NFPA 211), lined orrelined with a suitable liner, or replaced with a vent orchimney suitable for the equipment to be attached.

3.4 Common Venting Systems3.4.1 Venting Multiple AppliancesWhen common venting JVS or JVT natural draft

boilers with other appliances through one shared ductcalled a “common vent”, special care must be taken bythe installer to ensure safe operation. In the event thatthe common vent is blocked, it is possible, especiallyfor fan-assisted devices, to vent backwards throughnon-operating appliances sharing the vent, allowingcombustion products to infiltrate occupied spaces. Ifthe appliances are allowed to operate in thiscondition, serious injury or death may occur.

JVS/JVT Vent Pipe DiameterSize inch cm50 4 1075 5 13100 5 13125 6 15160 6 15225 7 18

Table 3. Exhaust Vent Connection Size.

3.3 Vent Pipe Sizing and GeneralInstallationAll vent installations and boiler stacking must be

designed and installed in accordance with all local,state or provincial codes and with:1. Chapter 7, “Venting of Equipment” of the

national Fuel Gas Code, ANSI 223.1 latestedition, or the applicable provisions of the localbuilding codes.

2. In Canada, CSA-B149.1.The draft diverter outlet is to be connected to an

unobstructed vent pipe of the same or larger diameter,terminating outside the building. The vent pipe musthave a listed vent cap and extend at least two feetabove any object with a ten foot radius. Allconnections should be made with rustproof sheetmetal screws.

IMPORTANT NOTE: Do not use sheet metal screwsat the snap lock joints of Type B gas vents.


WARNINGOperation of appliances with a blocked commonvent may lead to serious injury or death. Safetydevices must be implemented to prevent blockedcommon vent operation. If safe operation of allappliances connected to a common vent cannot beassured, including prevention of spillage of fluegasses into living spaces, common venting shouldnot be applied, and appliances should each bevented separately.

AVERTISSEMENTLe fonctionnement des appareils avec un systèmed’évacuation bloqué peut provoquer des blessuresgraves, voire la mort. Des dispositifs de sécuritédoivent être installés pour éviter le blocage dessystèmes d’évacuation. Si le fonctionnement detous les appareils connectés à un systèmed’évacuation commun ne peut pas être assuré, ycompris la prévention de la dispersion des gaztoxiques dans les espaces habités, on ne devraitpas installer un système d’évacuation commun etchaque appareil devrait être ventilé séparément.

It is for this reason that, in addition to followingproper vent sizing, construction and safetyrequirements from the National Fuel Gas Code, ANSIZ223.1 or in Canada, from CSA B149.1 as well as allapplicable local codes, it is required that installersprovide some means to prevent operation with ablocked common vent. It is suggested that a blockedvent safety system be employed such that if the switchfrom one appliance trips due to excessive stack spill orbackpressure indicating a blocked vent condition, thatall appliances attached to the vent be locked out andprevented from operating. As an additional precaution,it is recommended that a Carbon Monoxide (CO)alarm be installed in all enclosed spaces containingcombustion appliances. If assistance is required indetermining how a blocked vent safety system shouldbe connected to a LAARS product, please callApplications Engineering at (603) 335-6300.

Refer to the installation and operatinginstructions on all appliances to be common vented forinstructions, warnings, restrictions and safetyrequirements. If safe operation of all appliancesconnected to a common vent cannot be assured,including prevention of spillage of flue gasses intoliving spaces, common venting should not be applied,and appliances should each be vented separately.

3.4.2 Inspection of Commonly VentedAppliances

If the instrumentation of this boiler replaces anolder boiler in a common vent system with otherappliances, or if you remove additional appliancesfrom the common vent, all the appliances must bechecked for proper venting.

At the time of removal of an existing boiler, thefollowing steps shall be followed with each applianceremaining connected to the common venting systemplaced in operation, while the other appliancesremaining connected to the common venting systemare not in operation.1. Seal any unused openings in the common

venting system.Sceller toutes les ouvertures non utilisées dusystème d’évacuation.

2. Visually inspect the venting system for propersize and horizontal pitch and determine there isno blockage or restriction, leakage, corrosion andother deficiencies which could cause an unsafecondition.Inspecter de façon visuelle le systèmed’évacuation pour déterminer la grosseur etl’inclinaison horizontale qui conviennent ets’assurer que le système est examptd’obstruction, d’étranglement, de fuite, decorrosion et autres défaillances qui pourraientprésenter des risques.

3. Insofar as it is practical, close all building doorsand windows and all doors between the space inwhich the appliances remaining connected to thecommon venting system are located and otherspaces of the building. Turn on clothes dryersand any appliance not connected to the commonventing system. Turn on any exhaust fans, suchas range hoods and bathroom exhausts, so theywill operate at maximum speed. Do not operate asummer exhaust fan. Close fireplace dampers.Dans la mesure du possible, fermer toutes lesportes et les fenêtres du bâtiment et toutes lesportes entre l’espace où les appareils toujoursraccordés au système d’évacuation sont installéset les autres espaces du bùtiment. Mettre enmarche les sécheuses, tous les appareils nonraccordés au systéme d’évacuation commun ettous les ventilateurs d’extraction comme leshottes de cuisinière et les ventilateurs des sallesde bain. S’assurer que ces ventilateursfonctionnent à la vitesse maximale. Ne pas fairefonctionner les ventilateurs d’été. Fermer lesregistres des cheminées.

4. Place in operation the appliance being inspected.Follow the lighting instructions. Adjustthermostat so appliance will operatecontinuously.Mettre l’appareil inspecté en marche. Suivre lesinstructions d’allumage. Régler le thermostat defaçon que l’appareil fonctionne de façoncontinue.

5. Test for spillage at the draft hood relief openingafter 5 minutes of main burner operation. Use the


SECTION 4.Gas Connections

4.1 Gas Supply and PipingReview the following general instructions before

continuing the installation.

WARNINGThe Mini-Therm II JVS and JVT boilers aredesigned for use with either natural gas or LP gas.Check the rating plate to be sure that the boiler isdesigned to use the type of gas being supplied. DONOT ATTEMPT TO CONVERT THIS HEATERFOR USE WITH ANY OTHER TYPE OF FUEL.

AVERTISSEMENTLes appareils de chauffage à faibles sont conçuspour être utillsés avec du gaz naturel ou du gaz depétrole liquéfié (GPL). Vérifiez l’information inscritesur la plaque signalétique du pour vous assurer quel’appareil est conçu pour le type de gaz fourni. NEPAS ESSAYER DE CONVERTIR CET APPAREILÀ UN AUTRE TYPE DE GAZ.\

1. Gas piping installation must be in accordancewith the latest edition of ANSI Z223.1 and alllocal codes. In Canada, the installation must bein accordance with CSA-B149.1 and all localcodes that apply.

2. Check the gas supply to be sure that it is thesame as the gas indicated on the boiler’s plate.Mini-Therm II JVS and JVT boilers, as shippedfrom the factory, are certified to operate withinthe altitude range indicated on the rating plate. Ifa field conversion to a different altitude rangeshould be necessary, conversion parts areavailable for changing the altitude range of theheater. Refer to Doc. 6079 “Residential PartsPricing Book” to order the correct part number.

CautionPermanent damage to the gas valve will occur if thefollowing procedures are not followed.

AttentionVous endommagerez la soupape de gaz si vous nerespectez pas les procédures suivantes.

3. Use the figures in Table 4 to size the gas inletpiping from the gas meter to the heater. Check alllocal codes for compliance before installing theheater.

flame of a match or candle, or smoke from acigarette, cigar or pipe.Faire fonctionner le brûleur principal pendant 5min ensuite, déterminer si le coupe-tiragedéborde à l’ouverture de décharge. Utiliser laflamme d’une allumette ou d’une chandelle ou lafumée d’une cigarette, d’une cigare ou d’unepipe.

6. After it has been determined that each applianceremaining connected to the common ventingsystem properly vents when tested as outlinedabove, return doors, windows, exhaust fans,fireplace dampers and any other gas burningappliance to their previous conditions of use.Une fois qu’il a été déterminé, selon la méthodeinidquée ci-dessus, que chaque appareil raccordéau système d’évacuation est mis à l’air libre defaçon adéquate. Remettre les portes et lesfenêtres, les ventilateurs, les registres decheminées et les appareils au gaz à leur positionoriginale.

7. Any improper operation of the common ventingsystem should be corrected so the installationconforms with the National Fuel Gas Code,ANSI Z223.1. When resizing any portion of thecommon venting system, the common ventingsystem should be resized to approach theminimum size as determined using theappropriate tables in Appendix G in the NationalFuel Gas Code, ANSI Z223.1.Tout mauvais fonctionnement du systèmed’évacuation commun devrait être corrigé defaçon que l’installation soit conforme au nationalFuel Gas Code, ANSI Z223.1 et (ou) aux codesd}installation CSA-B149.1. Si la grosseur d’unesection du système d’évacuation doit êtremodifiée, le système devrait être modifié pourrespecter les valeurs minimales des tableauxpertinents de l’appendices F du National FuelGas Code, ANSI Z2231.1 et (ou) des codesd}installation CSA-B149.1.


NOTE: The boiler and all other gas appliancessharing the boiler gas supply line must be firing atmaximum capacity to properly measure the inletsupply pressure. Low gas pressure could be anindication of an undersize gas meter and/orobstructed gas supply line.8. The correct high fire burner manifold gas

pressure is stamped on the rating plate. Theregulator is pre-set at the factory, and normallyrequires no further adjustment. For two-stageunits (JVS100-225) be sure unit is able to fire atboth high and low fire.

9. Before operating the boiler, the complete gassupply system and all connections must be testedfor leaks using a leak detector solution. Do notuse an open flame.

CautionSome leak test solutions (including soap and water)may cause corrosion or stress cracking. Rinse thepiping with water after testing.

AttentionCertaines solultions d’essai d’étanchéité (y comprisl’eau et le savon) peuvent causer de la corrosion oude la fissuration. Rincez les tuyaux à l’eau apprèsl’essai d’étanchéité.

4.2 Special Precautions for LP GasLP Gas is heavier than air and can therefore

more readily collect or “pool” in enclosed areas ifprovision for proper ventilation is not made. Be sureto pay special attention to proper ventilation for LPgas. Locate boilers a safe distance from LP gascylinders and filling equipment. In the United States,consult the “National Fuel Gas Code” (NFPA 54 /ANSI Z223.1, latest edition) or in Canada, thePropane Installation Code (CSA-B149.1), any localcodes and fire protection authorities about specificinstallation restrictions in your area.

4. A sediment trap (drip leg) must be installedahead of the gas controls (see Figure 5). Fit thetrap with a threaded cap which can be removedfor cleaning.

5. Install a manual gas shutoff valve for service andsafety. Do not use a restrictive gas cock. Flexiblegas connectors, if used, must be CSA rated forthe total input rating of the boiler.

6. Disconnect the boiler and its individual shutoffvalve from the gas supply system during pressuretesting of the system at pressures higher than 1/2pounds per square inch (psi) (3.45 kilopascals[kPa]). If the test pressure is equal to or less than1/2 psi (3.45 kPa), close the manual shutoffvalve on the heater during the piping pressuretest.

7. If the gas supply pressure is less than required,check for undersized pipe between the meter andthe boiler, a restrictive fitting, or an undersizedgas meter. Gas supply pressures to the heater arelisted in Table 5.

NOTE: The maximum inlet gas pressure must notexceed the specified value. The minimum valuelisted is for the purpose of input adjustment. Referto Table 5.

DistanceFrom Gas

Meter

Boiler Size

50 75 100 125 160 225

Pipe Size

0-50'1/2 3/4 3/4 3/4 1 1

0-15m50-100'

3/4 3/4 3/4 1 1 1-1/415-30m100-200'

3/4 1 1 1 1-1/4 1-1/430-60m

Table 4. Natural Gas Pipe Size Requirements*

*Note: These figures are for Natural Gas (.65 Sp. Gr.), and arebased on 1/2" water column pressure drop. Check supplypressure with a manometer, and local code requirements forvariations. For LPG, reduce pipe diameter one size, butmaintain a 1/2" minimum diameter. A 'normal' number of Teesand elbows have been taken into allowance.

Figure 5. Typical design for a sediment trap/drip leg.

Supply Pressure Minimum MaximumNatural Gas 5.5 Inches WC 10.5 Inches WC

(1.3 kPa) (2.5 kPa)

LP Gas 10.0 Inches WC 13.0 Inches WC(2.4 kPa) (3.1 kPa)

Table 5. Gas Supply Pressure Requirements.

Gas SupplyInlet

TeeFitting

3 in.(76mm) Min.

Cap

Nipple

To EquipmentInlet


A full sized, 1¼" bypass with balancing valves isstrongly recommended for all systems, and requiredwhen: 1) the boiler is installed without primary-secondary piping in a multiple zone system; 2) whenthe return water temperature can be expected to belower than 120°F (44°C); or 3) whenever the systempiping on the outlet side of the boiler may allowreduced flow through the heat exchanger, causingexcessive temperature rise (see Section 5.2).Note: Laars strongly recommends a primary/secondary piping system for all installations,especially sizes 125, 160 and 225. In this system, acirculator is dedicated to pumping the boiler only. Thiscirculator should be sized for the boiler head loss andflow rate.

All precautions must be taken by the installer toinsure that a maximum temperature rise through theboiler does not exceed 30°F (17°C). The temperaturerise on boilers installed in multi-zone systems usingzone valves must be taken when the zone of thelongest length and/or the zone of the highest head lossis open.

A full size, 1¼" diameter by-pass withbalancing valve must be installed if a return watertemperature below 120°F (44°C) is expected underoperating conditions regardless of boiler size. Thismay be expected in many systems, including in-floor radiant and snow melt systems.

Adjusting the bypass:Refer to figure 7. Provide a means of measuring

temperature on the inlet pipe to the boiler such asusing a strap on or infrared themometer. Starting withboth balancing valves fully open, start the boiler.Adjust the balancing valve on the return to the systemslowly to provide 120°F (44°C) water at the inlet tothe boiler, leaving the bypass balancing valve fullyopen. As the system warms up, this valve may need tobe adjusted open. In rare cases, this valve will have tobe kept fully open, and the bypass balancing valveadjusted toward closed to prevent heated bypass waterfrom satisfying the call for heat when the system is upto temperature.

5.2 Alternate Auto-Bypass OperationUse of the Laars themostatic union, p/n 2400-

030, can provide automatic bypass operation inprimary - secondary piped systems (but cannot beused when primary - secondary piping is not used).The thermostatic union is installed on the outletpiping, after the bypass assembly. It can be used iinplace of a balancing valve. It opens fully at 140°F (seeFigure 6). Contact the factory for more information.

SECTION 5.Water Connections

5.1 Water PipingFigure 6 shows ‘typical’ plumbing installations.

Be sure to provide unions and isolation valves at theboiler inlet and outlet so it can be isolated for service.Check local codes for specific plumbing requirementsbefore beginning the installation.

An ASME pressure relief valve is supplied on allJV boilers, and is pre-set at 30 PSI. The valve outletpiping must discharge to a drain. Under nocircumstances should the relief valve piping be aclosed circuit.

A pressure reducing valve (automatic feed) mustbe used to maintain system at constant proper pressure(see Figure 6). Supply properly installed purge valvesto eliminate air from each circuit.

A drain valve is supplied with the boiler, and canbe found in the plastic bag shipped with each boiler.This valve is to be installed on the lower right side ofthe boiler, see Figure 1, and is used for draining theunit. To drain the boiler completely, open the drainvalve and remove the two drain plugs located onthe lower left side of the boiler.

Be sure to include air vent devices located at thehighest point in the system to eliminate trapped air,and an air elimination device near the outlet side ofthe JV boiler. Manual vent valves are recommended.

Hot water piping should be supported by suitablehangers or floor stands, NOT by the boiler. Due toexpansion and contraction of copper pipe,consideration should be given to the type of hangersused. Rigid hangers could transmit noise through thesystem caused by the piping sliding in the hangers. Itis recommended that padding be used when rigidhangers are installed.

Gas piping should also be supported by suitablehangers or floor stands, not the boiler.

A properly sized expansion tank must beincluded in the system. Laars offers an airchargeddiaphragm-type expansion tank, with an automaticfeed valve, which includes a pressure regulator set at12 psig. The part numbers are:

Less Than 20 Gallons in System A006680020 to 45 Gallons in System A0066900

5.1.1 By-pass PipingThe following information and suggestions are

made on by-pass piping as it affects the temperaturerise at the boiler. A boiler temperature rise must betaken on all JV boiler installations. If the temperaturerise exceeds 30°F (17°C) at full rate, it is an indicationthat the boiler is not receiving adequate water flow.Check the pump for any obstruction, replace the pumpwith a larger size where necessary, or install a systemby-pass as indicated in Figures 6 and 7.


Figure 6. Typical Plumbing Installations.

JV

FromSystem

ToSystem

NON-LOW TEMPERATURE SYSTEMS(120°F+ Return Temps)

Simple Primary/Secondary Piping - Hydronic - Not Low Temp

NOTE: All closed loop systems should include air elimination, expansion tank and feed water inlet. Place at point of lowest pressure (typicallyat the inlet of pump).NOTE: Ball valves should not be used as balancing valves. Only use for shutoff apps.

LOW TEMP SYSTEMS

JV

120°+

FromSystem

ToSystem

Primary/Secondary Piping with Variable Speed Injection

Variable SpeedControl

Pump

Pump

Isolation Valve

IsolationValve

The preferred piping configuration for JV boilers is always using primary/secondary piping.There are some applications that are acceptable without primary/secondary piping, see below.

FromSystem

ToSystem

Primary/Secondary Piping with Field Balancing(for Fixed Low Return Temperatures)

JV

Pump

Isolation Valve

IsolationValve

BalancingValveBalancing

Valve

Pump

FromSystem

ToSystem

Tempering Valve with System Loopand Boiler Loop Pump

JV

Pump

Isolation Valve

IsolationValve

TemperingValve

Pump

FromSystem

ToSystem

Primary/SecondarySystem Loop with Tempering Valve and Pump with Boiler Loop

with Tempering Valve and Pump

JV

Pump

Isolation Valve

IsolationValve

TemperingValve

Pump

TemperingValve

IsolationValve

IsolationValve

Pump

Pump

JV

FromSystem

ToSystem

Primary/Secondary Piping with By-Pass(for Fixed Low Return Temperatures)

Pump

IsolationValve

Pump

IsolationValve

BalancingValve

BalancingValve

Primary/Secondary Piping with Automatic By-Pass

Pump

Pump IsolationValve

IsolationValve

AutoBy-Pass

ValveFrom

System

ToSystem

JV

JV

FromSystem

ToSystem

Primary/Secondary Piping with LaarsThermostatic Union as an Automatic Bypass

Pump

IsolationValve

Pump

IsolationValve

LaarsThermostatic

UnionPN 2400-030

BalancingValve


Figure 6A. Typical Plumbing Installations.

KEY: PUMP CHECK VALVE VALVE ZONE VALVE UNION AUTO AIR BLEEDER

Air Scoop

JVBoiler

Bypass Valve(Ball Valve)

Zone Pump

Purge System

OptionalPump

Location

FeedWaterInlet

Air Cushion TypeExpansion Tank

OptionalFeed WaterInlet

SystemLoop

ExpansionTank

PumpAir Scoop

FeedWater

Single Circuit System

Multi-ZoneValve System

Multi-ZonePumpSystem

Figure 6B. Typical Plumbing Installations.


5.3 Flow RequirementsAll high recovery, low volume water boilers

must have adequate flow for efficient operation. Pumpselection is critical to this goal, and pumps should beselected to provide for system design watertemperature rise. Table 6 details temperature rise andwater flow (GPM) for the Mini-Therm boilers.Damage from improper flow is not warranted.

Failure to insure proper water flow through theheat exchanger of the boiler will void the Laarswarranty. Flow can be verified by measuring thedifference in water temperatures between the boilerinlet and outlet. For example: For a JV-100

installation, the inlet water temperature is 160°F(71°C), and the outlet temperature is 180°F (82°C) atNormal Input Rate from the rating plate. That meansthere is a 20° (11°C) temperature rise through theboiler. According to Table 1, that would indicate aflow rate of 8 GPM (0.5L/S). Temperature rise mustbe measured with the longest (highest head) zonecalling for heat alone.

Other factors to be considered before selecting apump are pipe size, the number of fittings throughoutthe system, smoothness of the interior surface of thepipe, the quantity of water flowing through the pipe,whether a glycol solution is being used, and the totallength of piping in the system. Table 7 providesexamle pump selection criteria using Type L copperpiping, one zone valve and up to eight elbows forsingle zone systems. Consult the factory or a qualifiedsystem designer if you have more fittings, differentsize or type of pipe (especially in retrofit situations),or some other unique system configuraiton notillustrated in this manual.

Figure 7. By-pass Piping.

Balancing Valveor optional

thermostatic union,Laars P/N 2400-030.(Primary/Secondary

only)

ToSystem

FromSystem

In(Return)

Out(Supply)

DripLeg

Left Side View

A full size by-pass must be installed. Size

1/2" Pipe 3/4" Pipe 1" Pipe 1-1/4" Pipe

Pump H.P. Pump H.P. Pump H.P. Pump H.P.

1/25 1/12 1/25 1/12 1/6 1/25 1/12 1/6 1/25 1/12 1/6

50 50 99 390 680 * * * * * * *

75 * 35 160 300 460 640 * * * * *

100 * * 77 150 260 330 620 * * * *

125 * * 27 80 140 170 360 600 * * *

160 * * * 25 72 57 160 330 190 480 *

225 * * * * * * * 110 * 69 330

*A circulator and/or primary/secondary piping are required. Consultfactory.1. Chart is based on 30°F (17°C) maximum temperature rise.2. Calculations are based on Type L copper tubing with one

zone valve and eight elbows.3. Typical circulating pumps: 1/25 HP=Taco 007, B&G LR-20 or

SLC-25, Grundfos UP15-42F, or equivalent. 1/12 HP=B&G LR-12, Grundfos UP26-42F, or equivalent. 1/6 HP=B&G seriesHV, Grundfos UP43-75, or equivalent.

Table 7. Maximum Suggested Circuit Length in Feet.

Size

15°F 8°C 20°F 11°C 25°F 14°C

Flow Rate Headloss Flow Rate Headloss Flow Rate Headloss

gpm l/s ft m gpm l/s ft m gpm l/s ft m

50 5.3 0.3 0.3 0.1 4.0 0.3 0.2 0.1 3.2 0.2 0.1 0.0

75 8.0 0.5 0.6 0.2 6.0 0.4 0.3 0.1 4.8 0.3 0.2 0.1

100 10.7 0.7 1.3 0.4 8.0 0.5 0.7 0.2 6.4 0.4 0.5 0.2

125 13.3 0.8 2.2 0.7 10.0 0.6 1.3 0.4 8.0 0.5 0.8 0.2

160 17.0 1.1 2.5 0.8 12.8 0.8 1.8 0.5 10.2 0.6 1.2 0.4

225 24.0 1.5 5.0 1.5 18.0 1.1 3.1 0.9 14.4 0.9 1.9 0.6

Table 6. Temperature Rise °F °C.

gpm = Water Flow in gallons per minute. l/s = Water flow in liters per second.ft = Pressure drop (headloss) through the boiler in feet of water. m = Pressure drop (headloss) through the boiler in meters of water.

Notes: 1. Shaded area is the recommended flow and temperature rise.2. Temperature rise and associated flow rates are based on high fire operation at the Normal Input Rate from the rating plate.

BalancingValve


5.4 Chilled Water SystemsIf the boiler is installed in conjunction with

refrigeration systems, it shall be installed so that thechilled medium is piped in parallel with the heatingboiler with appropriate valves to prevent the chilledmedium from entering the heating boiler.

When boiler piping is connected to heatingcoils, which are in close proximity to refrigerated aircirculation, there must be flow control valves or otherautomatic methods to prevent gravity circulation ofthe boiler water during the cooling cycle.

5.5 Oxygen Permeable SystemsThe JV boiler must not be direct connected to a

heating system utilizing oxygen permeable tubing.Provide a water-to-water heat exchanger betweensystems to prevent corrosion of ferrous metals such asthe boiler’s piping wet walls, etc. Air eliminationdevices are not sufficient protection, and corrosiondamage is not covered under the limited warranty.

5.6 Anti-FreezeNon-toxic heating system anti-freeze may be

added to the hydronic system provided theconcentration does not exceed 50%, and the anti-freeze contains an anti foamant. Follow the anti-freezemanufacturer’s recommendations for yearly orbiannual replacement of system anti-freeze.

SECTION 6.Electrical

WARNINGELECTRICAL SHOCK HAZARD. This boilercontains wiring that carries high voltage. Contactwith these wires may result in severe injury ordeath.

AVERTISSEMENTPOSSIBILITÉ DE CHOCS ÉLECTRIQUES. Cesystème de chauffage contient du filage de hautvoltage. Un contact avec ces fils peut résulter endes blessures sérieuses ou la mort.

CautionLabel all wires prior to disconnection when servicingcontrols. Wiring errors can cause improper anddangerous operation. Verify proper operation afterservicing.

AttentionAu moment de l’entretien des commandes,étiquetez tous les fils avant de les débrancher. Deserreurs de câblage peuvent entraîner unfonctionnement inadéquat et dangereux.

6.1 General InformationWiring connections must be made exactly as

shown in the wiring diagram found on the inside ofthe control box cover (see Figure 8). The boiler mustinclude a definite means of grounding. There is abonding lug, where a bond wire must be attached.

Figure 8. Field Wiring Connections.

Transformer BLK

BLK - Hot

WHT - Neutral

WHT - Neutral

BRN - Hot

On = Call

for heat

Power

Supply

115V AC

60 Hz

To Pump

115V AC

3/4 H.P.

Max

BRN WHT

Pump Relay

115V Field Wiring

115V Factory Wiring

GRN - Ground

6.2 Main PowerElectrical wiring must be in accordance with the

latest edition of the National Electric Code (NEC),ANSI/National Fire Protection Association (NFPA)70, unless local code requirements indicate otherwise.

The heater comes factory-wired intended foruse with 115 Volt, 60 Hz AC field electrical supply.

Making electrical connections must be done by acertified electrician only, as with all wiring. Be surethat the power source to the heater is turned off ordisconnected before servicing.

To wire the Mini-Therm II boiler to a 115V / 60Hertz (Hz) electrical source:1. Remove the two screws attaching the front cover

of the control box.2. There are four wires coiled in the area on the

right side of the control box, supplied with wirenuts: 2 black wires twisted together, a white wireand a brown wire (see Figure 8).

3. Follow the schematics in Figure 9. Remove thewire nut from the two black wires, and connectthe hot lead from a 115V power supply to bothwires. Secure the three wires with the wire nut.The white, neutral wire should be joined to theother neutral lead coming from the 115V powersupply, and the neutral lead coming from thepump. The brown wire attaches to the hot side ofthe pump.NOTE: No external junction box is required.

4. Attach the leads from the wall thermostat to theR and W terminals on the terminal strip, locatedon the left side of the control box.


1

2

3

4

56

BK-BLACKW-WHITER-REDY-YELLOWBL-BLUEBR-BROWNO-ORANGEP-PURPLE

SPARK IGNITION WIRE115V-FACTORY WIRED115V-FIELD WIRED24V-FACTORY WIRED24V-FIELD WIRED

IF ANY OF THE ORIGINAL WIRE(AS SUPPLIED WITH THEAPPLIANCE) MUST BE REPLACEDIT MUST BE REPLACED WITHAPPLIANCE WIRING MATERIALSUITABLE FOR 105 DEGREES COR ITS EQUIVALENT.

G-GREEN

SERTED INTO THE VENT

THE BOILER WILL NOTOPERATE WITHOUT THEAUTOMATIC VENT DAMPERTHE VENT DAMPER WIREHARNESS MUST BE IN-

DAMPER RECEPTACLE.

IN CANADA: SOME UNITS

ARE SUPPLIED WITH VENTDAMPER JUMPER PLUG.DO NOT REMOVE JUMPERUNLESS VENT DAMPER ISTO BE INSTALLED.

R

W

A

O

RECEPTACLEVENT DAMPER

Y

P

R

R

P

BL

R

115V24V

GROUNDINGCONDUCTOR

115/60HZPOWER SUPPLY

PUMPRELAY

TRANSFORMERHOT

NEUTRAL

W

BK

BK

PUMP(FIELDSUPPLIED)

ZONE

YY

R

G

BR

HEATINGSPACE

HW VR8304GAS VALVE

Y

Y

BR

O

TERMINALSTRIP

WALLTHERMOSTAT

(FIELDSUPPLIED)

Y

AQUASTAT(OPTIONAL) LIMIT

HIGH

R R

BK

POWER VENTER

RECEPTACLE

SEE DOC. 1077

JUMPER Y

BLOCKEDVENT

SAFETYSWITCH

ROLL-OUTSWITCH

BK

BK

PV

MV/PV

MV

SP

AR

K

IGNITIONCONTROL

PILOT BURNERWITH SPARKELECTRODESENSOR

H2019700C

MODEL JVS50 & 75

MV

MV/PV

PV

GND

24V (GR)

24V

TH-W

MV

SPARK

1

2

3

4

5

6

7

8

9

REMOTE FLAME SENSOR

HIGH ALTITUDE (OPTIONAL)

Figure 9a. Wiring Diagram, Spark Ignition System (JVS 50 & 75).

SwitchSafety

Roll-OutBlockedVent

SafetySwitch

Space HeatingPump

(Field Supplied)

ReceptacleDamper

Vent

ReceptacleVenterPower

Jumper

RWR

A

ZonePumpRelay

ZonePumpRelay

FieldThermostat

Supplied

LimitHighOptional

Aquastat

TerminalTerminalBoiler Boiler

TerminalBoiler

Fuse

115V

24V

3

RelayPumpZone

110VHot

110VNeutral

1

4

6

ZonePumpRelay

6 3 2 1 4 524V PV PV MV GND GND

MV/ 24V

Ignition Control

SP

AR

K

PVPV

MV/ MV

Gas ValveHW VR8304

Remote Flame SensorHigh Altitude (Optional)

Figure 9b. Schematic, Spark Ignition System(JVS 50 & 75).

5. When using a Laars or field supplied powerventer, the proving switch must be connected inseries with the hi-limit. See wiring diagrams,Document 1077. See Figure 1 for vent damperconnections.

6. Check the boiler wiring and pump for correctvoltage, frequency and phase. If the pump circuitis other than 115V, be sure there is anappropriate transformer or relay installed. Thepump relay is suitable for pumps of ¾ HP orless.

7. For systems with multiple zone pumps or valves,see Figure 10.A means of disconnecting the electrical supply

must be provided within sight of the boiler. The pumpand boiler must be wired as shown to insure that thepump is running whenever the boiler is firing.


Figure 9c. Wiring Diagram, Standing Pilot System (JVT).

Figure 9d. Schematic, Standing Pilot System (JVT).


SP

AR

K

MVMV/PVPVGND24V (GR)24VTH-WMVSPARK

123456789

W W

B B

R R

LO HI

MV

C

PV

HI

Pilot Burner WithSpark Electrode

Sensor

Remote Flame SensorHigh Altitude

(Optional)Two-StageAquastat

Two-StageGas Valve

HW VR8304

SwitchSafety

Roll-OutBlockedVent

SafetySwitch

Space HeatingPump

(Field Supplied)

ReceptacleDamper

Vent

ReceptacleVenterPower

Jumper

RWR

A

ZonePumpRelay

ZonePumpRelay

FieldThermostat

Supplied

LimitHighOptional

Aquastat

TerminalTerminalBoiler Boiler

TerminalBoiler

Fuse

115V

24V

3

RelayPumpZone

110VHot

110VNeutral

1

4

6

ZonePumpRelay

Ignition Control

Figure 9e. Wiring Diagram, Spark Ignition, Two-Stage (JVS 100-225).

BK-BLACKW-WHITER-REDY-YELLOWBL-BLUEBR-BROWNO-ORANGEP-PURPLE

SPARK IGNITION WIRE115V-FACTORY WIRED115V-FIELD WIRED24V-FACTORY WIRED24V-FIELD WIRED

G-GREEN

IF ANY OF THE ORIGINALWIRE (AS SUPPLIED WITHTHE APPLIANCE) MUSTBE REPLACED, IT MUSTBE REPLACED WITHAPPLIANCE WIRINGMATERIAL SUITABLEFOR 105 DEGREES COR ITS EQUIVALENT.

1

23

4

56

THE BOILER WILL NOT OPERATE WITHOUT THEAUTOMATIC VENT DAMPER. THE VENT DAMPER WIREHARNESS MUST BE INSERTED INTO THE VENTDAMPER RECEPTACLE.

: SOME UNITS ARE SUPPLIED WITH VENTDAMPER JUMPER PLUG. DO NOT REMOVE JUMPERUNLESS VENT DAMPER IS TO BE INSTALLED.

IN CANADA

R

W

A

O

RECEPTACLEVENT DAMPER

Y

P

R

R

P

BL

R

115V24V

GROUNDINGCONDUCTOR

115/60HZPOWER SUPPLY

PUMPRELAY

TRANSFORMERHOT

NEUTRAL

W

BK

BK

PUMP(FIELDSUPPLIED)

ZONE

YY

R

G

BR

HEATINGSPACE

TWO-STAGEGAS VALVEHW VR8304

BR

O

TERMINALSTRIP

WALLTHERMOSTAT

(FIELDSUPPLIED)

Y

AQUASTAT(OPTIONAL) LIMIT

HIGH

R R

BK

POWER VENTERRECEPTACLE

SEE DOC. 1077

JUMPER

Y

BLOCKEDVENT

SAFETYSWITCH

ROLL-OUTSWITCH

BK

BL

SP

AR

K

IGNITIONCONTROL

PILOTBURNER

WITHSPARK

ELECTRODESENSOR

H0267300-

MODEL JVS100-225

MVMV/PVPVGND24V (GR)24VTH-WMVSPARK

1

2

3

4

5

6

7

8

9

REMOTE FLAME SENSORHIGH ALTITUDE(OPTIONAL)

W W

B B

R R

LO HI

MV

C

PV

HI

BK

Y

Y

BR

TWO-STAGEAQUASTAT

Y

Figure 9f. Schematic, Two-Stage (JVS 100-225).


Figure 10. Multiple Zone Wiring.

For primary/secondary pumping: Connectto "W" in lieu of "A." Boiler relay is used forboiler pump and connection to "W" willenergize boiler pump when any zone iscalling for heat.

Wiringwith TacoZone Valves

Wiring withHoneywellZone Valves

Wiringwith MultipleZone Pumps


6.3 Grounding

WARNINGThe boiler must be electrically grounded inaccordance with the requirements of the authorityhaving jurisdiction or, in the absence of suchrequirements, with the latest edition of the NationalElectrical Code, ANSI/NFPA 70, in the U.S. andwith latest edition of CSA C22.1 Canadian ElectricalCode, Part 1, in Canada. Do not rely on the gas orwater piping to ground the metal parts of the boiler.Plastic pipe or dielectric unions may isolate theboiler electrically. Service and maintenancepersonnel who work on or around the boiler may bestanding on wet floors and could be electrocuted byan ungrounded boiler.

AVERTISSEMENTLa chaudière doit être mise à la terre selon lesexigences officielles locales ou, en l’absence detoute instruction officelle, l’installation doit êtreconforme au National Electrical Code, ANSI/NFPA70, aux États-Unis et avec la dernière édition duCode électrique canadien CSA C22.1, Partie 1, auCanada. N’utilisez pas la tuyauterie de gaz oud’eau pour mettre à la terre les parties métalliquesde la chaudière. Les unions diélectriques ou avectuyau en plastique peuvent isoler la chaudièreélectriquement. Les membres du personnel deservice et d’entretien qui travaillent sur et autour dela chaudiére peuvent marcher dur des planchersmouillés et pourraient se faire électrocuter par unechaudière non mise à la terre.

6.4 Auxiliary Devices6.4.1 Flow SwitchIf the system includes a flow switch, it should be

wired in series with the high-limit switch. The boilerwill not fire unless the pump is running and the flowswitch is closed.

Field installed safety devices and operatingcontrollers, such as a valve end switch, draft switches,relays, timers, and outdoor temperature reset devices,can be connected to the boiler through the wallthermostat circuit. Do not exceed a draw of 30VA onthe transformer secondary.

6.4.2 Heat AnticipatorFor single zone installations, the wall thermostat

heat anticipator should be set at 0.5 amperes. Formulti-zone installations, have a qualified electricaltechnician make the necessary measurements toproperly set the thermostats.

SECTION 7.Operating Instructions

7.1 Normal OperationThe Laars Mini-Therm II JVS and JVT boilers

are capable of automatic operation based on a call forheat at present temperatures. The boiler has an internalsafety system which allows operation in a variety ofconditions and prevents operation when certainadverse conditions are encountered.

When the wall thermostat calls for heat and theboiler is powered, an operating cycle is initiated. (Oncontinuous pilot ignition models (JVT) the pilot mustalso be lit). The pump relay turns on the pump, thedamper activator rotates the damper blade to the openposition and the indicator light comes on.

On spark ignition models (JVS 50-75), if thewater temperature is below the limit setting, theignition module lights the pilot and checks the flameexistence. After the pilot is proven to be lit, theignition module opens the main gas valve and themain burners ignite.

On 2-Stage spark ignition models (JVS 100-225), if the water temperature is below the limitsetting, the ignition module lights the pilot and checksthe flame existence. After the pilot is proven to be lit,the ignition module opens the main gas valve and themain burners ignite. The main gas valve is controlledby the two-stage operating control (see Figure 11) andwill cycle between high, low and off as the loaddemands.

Figure 11. L6008G Operation.

1

2

TEMPERATURERISE

LOWFIRE

BREAKS R-BMAKES R-WON RISE

BREAKS R-WMAKES R-BON FALL

INTERSTAGEDIFFERENTIAL

BREAKS R-BMAKES R-WON RISE

BREAKS R-WMAKES R-BON FALL

BOILER INLETSETPOINT

(ADJUSTABLE,FACTORY SET

AT 140°F)

LEFT SWITCHDIFFERENTIAL

RIGHT SWITCHDIFFERENTIAL

1

2

2

DIFFERENCE BETWEEN THE TEMPERATURES AT WHICH THETWO SWITCHES MAKE R-W. FACTORY SET AT 10°F (6.6°C)

TWO SPDT SWITCHES OPERATE IN SEQUENCE. EACHSWITCH DIFFERENTIAL AT APPROXIMATELY 3°F (1.7°C)

HIGHFIRE


On continuous pilot ignition models (JVT), if thewater temperature is below the limit setting, theignition module opens the main gas valve, and themain burners ignite.

Operation will continue on all ignition systemsuntil either the wall setting thermostat is satisfied orthe high-limit thermostat opens. The burners and pilot(on JVS models) shut-off and the pump relay turns offthe pump. The damper activator rotates the damperblade to the closed position and the indicator lightgoes off.

When the room temperature falls below the wallthermostat setting, the cycle repeats.

Note: When equipped with a pump delay option,the pump runs for a short time after the burners turnoff and the damper closes.

7.2 Start-up7.2.1 Filling the System

NOTE: It is strongly recommended that the system becleaned and flushed to remove scale, oil, paste, flux,etc., before the system is filled.

It is crucial to the efficient operation of thesystem that all air be removed from the circuit. Forthis reason, an air scoop and vent should be locatedclose to the boiler outlet, and there should be aminimum distance between cold water feed andsystem purge valve.1. When the system has been completely installed,

close all air vents and open the makeup watervalve. Allow the circuit to fill slowly.

2. Adjust the pressure to provide a minimum of 12psi (82.7kPa) at the highest point in the circuit. Ifa pressure regulator is also installed in the line,adjust it to the same pressure.

3. Close all gate valves. Purge one circuit at a timeas follows:a. Open one circuit drain valve and let water

drain out for at least 5 minutes. Be certainthere are no air bubbles visible in the waterstream before closing the drain valve.

b. Repeat this procedure for each circuit.4. Open all gate valves after all circuits have been

purged.5. Run the system circulating pump for a minimum

of 30 minutes with the boiler shut off.6. Open all strainers in the system, and check for

debris.7. Recheck all air vents as described in Step 3 above.8. Some expansion tanks require visual inspection

of liquid level. If necessary, inspect the liquidlevel in the expansion tank. With the systemfull of water, and under normal operatingpressure, to ensure proper water level in theexpansion tank.

9. Start up boiler according to the proceduresdescribed in Section 7 and operate the system,

including the pump, boiler, and radiation units,for one hour.

10. Recheck the water level in the expansion tank,if necessary. If it exceeds ½ of the volume ofthe tank, open the tank drain and reduce thewater level.

11. Shut down the entire system, and vent allradiation units and high points in the system.

12. Close the water makeup valve and check the strainerin the pressure reducing valve for sediment ordebris. Reopen the water makeup valve.

13. Verify system pressure with the boiler pressuregauge before beginning regular operation.

14. Within 3 days of start-up, recheck and bleed allair vents and the expansion tank using theseinstructions.

15. In systems piped with cross-linked polyethylenetubng (PEX) it is essential that all air is purgedfrom all zones in the system to prevent PEXtubing failure.

7.2.2 Boiler Start-up

WARNINGFor your safety, when starting the boiler, keep yourhead and face well away from the burner area toprevent any risk of personal injury.

AVERTISSEMENTPour votre sécurité personnelle lorsque vousmettez l’appareil en marche, tenez votre tête etvotre visage loin du brûleur pour éviter tout risquede blessure.

WARNINGVent pipes, and heater tops get hot! These surfacescan cause serious burns. Do not touch thesesurfaces while the heater is in operation.

AVERTISSEMENTLes tuyaux d’aération et le dessus de l’appareildeviennent chauds! Ils peuvent causer de gravesbrûlures. Ne touchez pas à ces surfaces lorsquel’appareil est en marche.

CautionDo not use this boiler if any part has been underwater. Immediately call a qualified servicetechnician to inspect the heater and replace anypart of the control system and any gas controlwhich has been under water.

AttentionN’utilisez pas cet appareil s’il a été plongé dansl’eau, même partiellement. Faites inspecterl’appareil par un technicien qualifié et remplaceztoute partie du systéme de contrôle et toutecommande qui ont été plongés dans l’eau.


CautionShould overheating occur or the gas supply fail toshut off, do not turn off or disconnect the electricalsupply to the pump. Instead, shut off the gas supplyat a location external to the appliance.

AttentionEn cas de surchauffe ou si l’admission de gaz nepeut être coupée, ne pas couper ni débrancherl’alimentation électrique de la pompe. Fermer plutôtle robinet d’admission de gaz à l’extérieur del’appareil.

CautionDo not attempt repairs on the gas controls orappliance. Tampering is dangerous and voids allwarranties.

AttentionNe tentez pas d’effectuer des réparations ausystème de régulation du débit du gaz ou àl’appareil. Toute modification non autorisée estdangereuse et entraîne l’annulation de toutes lesgaranties.

CautionKeep all objects off the top of the boiler. Blocking airflow could damage the heater, and may void thewarranty.

AttentionNe posez aucun objet sur le dessus de l’appareil. Ilpourrait empêcher la circulation de l’air, ce quirisquerait d’endommager, l’appareil et d’annuler lagarantie.

7.3 Lighting and Shutdown Procedures

WARNINGDo not attempt to light the boiler with the burnercover off. Doing so may cause severe bodily injury.

AVERTISSEMENTNe tentez pas d’allumer l’appareil sans que la soiten place. Vous pourriez être victime de blessurescorporelles graves.

Before starting your boiler, be sure that all of thefunctions and limits of the JVS and JVT boilers havebeen set according to the previous section of thismanual (Section 7.2). Follow the instructions outlinedbelow. Read and follow all safety instructions first. Amore detailed set of lighting and shutdowninstructions are listed on the label located on theboiler.

NOTE: If your boiler is configured to operate on LPgas and the LP tank runs out of fuel, turn off gas atthe boiler. After the tank is refilled, the boiler mustbe relit following the instructions found on the boiler.DO NOT attempt repairs on the gas control orheater. Tampering is dangerous and voids allwarranties.

WARNINGIf the information in these instructions are notfollowed exactly, a fire or explosion may resultcausing property damage, personal injury or death.

AVERTISSEMENTAssurez-vous de bien suivre les instructionsdonnées dans cette notice pour réduire auminimum le risque d’incendie ou d’explosion oupour éviter tout dommage matériel, toute blessureou la mort.

7.3.1 Lighting the BoilerLighting instructions are as follows:

1. Verify that the pump system is operatingproperly:a. Shut off the manual gas valve located

outside the boiler.b. Raise the wall thermostat high enough to

call for heat.c. The pump should come on immediately. If

it doesn't, test the electrical circuits.2. Pilot Information:

a. The JVS boilers do not require manuallighting. The pilot is controlled by theautomatic ignition system.

b. The JVT boilers do require manual pilotlighting. For access to the pilot burner,remove the louvered airbox cover byloosening the two thumb screws.

c. Different models of the JV boiler utilizevarious gas valves. Although the gas valvesmay have different control knobs, they areall similar in operation. The JVS gas valvehas a two-position knob, ON and OFF. TheJVT valve has a three-position knob, ON,OFF and PILOT, some models come withextra push-button (see Figure 12).

Figure 12. Gas Valves.


15. Replace control box cover.16. Restore power to the boiler and adjust the

thermostat high enough to call for heat to verifythe boiler is operating properly.

17. JVS 100-225 ONLY - Adjust two-stageoperating control setting to maximum, verifyhigh fire operation. Reduce setting to just belowthe return water temperature and verify low fireoperation.

18. JVS 100-225 ONLY - Set two-stage operatingcontrol to desired low fire set point. Generally20°F below desired loop temp. i.e. for 180°Floop, set two stage operating control at 160°F.Adjust as necessary to maintain proper looptemperature.

19. Set the thermostat to the desired temperature.

7.3.2 Shutdown7.3.2.1 Main Burner Shutdown (JVT Only):

1. Lower the wall thermostat setting so that there isno call for heat.

2. To turn off the main burners turn the gas valveknob clockwise until it stops at pilot.

7.3.2.2 Complete Shutdown:1. Lower the wall thermostat setting so that there is

no call for heat.2. Turn off all electrical power to the boiler.3. Turn the gas valve knob clockwise to “OFF”. Do

not force the knob.4. Shut off the external gas supply valve to the

boiler.

7.4 High Altitude BurnerAir Shutter Adjustment

DANGERThis procedure must be followed exactly andmust be performed by a qualified installer orwarranty may be voided.

DANGERCette manière de procéder doit être faiteexactement et accomplie par un installateur qualifiésous risque d’annulation de la garantie.

3. BEFORE LIGHTING smell all around theappliance area for gas. Be sure to smell next tothe floor because some gas is heavier than airand will settle on the floor.

a. WHAT TO DO IF YOU SMELL GASa.1 Do not try to light any appliance.a.2 Do not touch any electric switch; do not use

any phone in your building.a.3 Immediately call your gas supplier from a

neighbor's phone. Follow the gas supplier'sinstructions.

a.4 If you cannot reach your gas supplier, callthe fire department.

All Models:4. Shut off electrical power to the boiler.5. Turn the gas valve knob clockwise to OFF.

Use only your hand to push in or turn the gascontrol knob. Never use tools. If the knob willnot push in or turn by hand, don't try to repair it,call a qualified service technician. Force orattempted repair may result in a fire or explosion.

6. Wait five (5) minutes to clear out any gas. Thensmell for gas, including near the floor. If yousmell gas, STOP! Follow 7.3.1 (3.)a. If you don'tsmell gas, go to the next step.JVS Models: (JVT skip 7 )

7. Turn gas valve knob counterclockwise to ON.Restore power to the boiler, and set the thermostatto the desired temperature. The pilot willautomatically ignite when there is a call for heat.JVT Models: (Continuous Pilot)(JVS skip to step 16)

8. Remove louvered burner cover by loosening thetwo thumb screws to access the pilot burner.

9. Remove the control box cover to fully access thegas valve.

10. Find pilot - follow metal tube from gas control.The pilot is on the right hand side of the firstburner.

11. Turn knob on gas control counterclockwiseto PILOT.

12. Push in control knob or push-button all the wayand hold in. Immediately light the pilot with amatch using the match holder. Continue to holdthe control knob in for about one (1) minute afterthe pilot is lit. Release knob and it will pop backup. Pilot should remain lit. If it goes out, repeatsteps 2 through 8.a. If the knob does not pop up when released,

stop and immediately call your servicetechnician or gas supplier.

b. If the pilot will not stay lit after severaltries, turn the gas control knob to OFF andcall your service technician or gas supplier.

13. Replace the louvered airbox cover and tightenthe two thumb screws securely.

14. Turn gas control knob counterclockwise to ON.


DANGERRead and understand this entire procedureprior to proceeding. Improper adjustment ofhigh altitude shutters may result in a fire,explosion, and/or high levels of toxic gaseswhich may cause property damage, personalinjury, or loss of life.

DANGERLisez la manière de procéder dans sa totalité etcomprenez-la bien avant de commencer. Unajustement inadéquat des volets en haute altitudepeut provoquer un incendie, une explosion, et/oudes niveaux élevés de gaz toxiques qui pourraientcauser des dégâts matériels, des blessurespersonnelles, voire la mort.

1. STOP! Read the safety information above.2. Perform System Start-Up in accordance with

Section 7.2 of this manual.3. Remove burner cover by loosening two (2)

thumbscrews.4. Observe flame pattern on all burners. If the flame

on any burner is pulsing, unstable or liftingcontinue with this procedure. Otherwise skip tostep 10.

5. On all burners exhibiting an abnormal flame,loosen but do not remove the air shutter lockingscrew using a 5/16 inch wrench (see Figure 12).

6. On each affected burner, slowly close the airshutter until a normal flame is observed then re-tighten its associated locking screw.

7. Turn the boiler off.8. Perform System Start-Up in accordance with

Section 2A of this manual.9. Observe flame pattern on all burners. If the flame

on any burner is pulsing, unstable or lifting thenrepeat steps 5 and 6 until all burners areexhibiting a normal flame.

10. Re-install the burner cover and tighten it inplace.

SECTION 8.Maintenance

8.1 General Maintenance

WARNINGImproper installation or maintenance can causenausea or asphyxiation from carbon monoxide influe gases which could result in severe injury, ordeath.

AVERTISSEMENTUne installation ou un entretien inadéquat peutcauser la nausée ou l’asphyxie en raison dumonoxyde de carbone présent dans les gaz decombustion et même entraîner des blessuresgraves ou la mort.

WARNINGSERVICING SAFETYSome of the servicing procedures for the LaarsMini-Therm II JVS and JVT boilers are hazardousbecause they involve fuel gas, electricity, movingparts and procedures which require testing ortemporary bypass of safety controls. For thisreason, the heater must be serviced only by aqualified professional service technician.IMPROPER SERVICE HAZARDThe Mini-Therm II JVS and JVT boilers incorporateunique design features. Incorrect service of thisboiler can result in personal injury or damage toproperty. To avoid such hazards, the heater mustbe serviced only by a qualified professional servicetechnician.

AVERTISSEMENTPRÉCAUTIONS LORS DES RÉPARTATIONS ETDE L’ENTRETIENCertaines procédures d’entretien et de réparationdes appareils de chauffage à faibles émissionsprésentent des changers, car elles mettent en jeudes gaz combustibles, des composants électriques,des pièces mobiles et des procédures quinécessitent des mises à l’essai ou la dérivationtemporaire des commandes de sécurité. Pour cetteraison, l’appareil de chauffage doit être entretenu etréparé uniquement par un technicien professionnelqualifiéDANGERS D’UN ENTRETIEN INADÉQUATLes appareils de chauffage à faibles émissionscomportent des caractéristiques techniquesuniques. Une réparation ou un entretien inadéquatpeut entraîner des blessures corporelles ou desdommages à la propriété. Pour cette raison,l’appareil de chauffage doit être entretenu et réparéuniquement par un technicien professionnelqualifié.Figure 13. Air Shutter Adjustment.

LOCKING SCREW(5/16" HEAD)

AIR SHUTTERBURNER


1. Lubricate the water circulating pump per theinstructions on the pump.

2. If a strainer is employed in a pressure reducingvalve or the piping, clean it every six months.

3. At start-up, and periodically thereafter, theburner flame should be observed. If the flamehas the appearance of ‘sooting’ tips, check fordebris near the orifices and call the servicetechnician.

4. Inspect the venting system for obstruction,leakage or corrosion at least once a year.

5. Do not store or use gasoline or other flammablevapors, liquids or chemicals in the vicinity ofthis or any other appliance.Ne pas entreposer ni utiliser d’essence nid’autres vapeurs ou liquides inflammables àproximité de cet appareil ou de tout autreappareil.

6. Do not use this boiler if any part has been underwater. Immediately call a qualified servicetechnician to inspect the heater and replace anypart of the control system and any gas controlwhich has been under water.N’utilisez pas cet appareil s’il a été plongé dansl’eau, même partiellement. Faites inspecterl’appareil par un technicien qualifié et remplacez toute partie du système de contrôle et toutecommande qui ont été plongés dans l’eau.

7. Be sure that all combustion air and ventilationopenings are unobstructed.

8. Upon completion of the installation, inspect theexternal surfaces of the heat exchanger forfouling based on the following schedule:24 hours 7 days 30 days 90 daysOnce every six months thereafter.

9. If the boiler is not going to be used for longperiods of time in locations where freezingoccurs, it should be completely drained of allwater. To accomplish this, there is a drain valveon the right side of the boiler which can beopened. This will drain the right side of theboiler. There are two plugs located on the leftside of the heater which must be removed todrain that side. Both sides must be drained.

10. The gas and electric controls on the boiler areengineered for long life and dependableoperation, but the safety of the equipmentdepends on their proper functioning. It is

strongly recommended that the basic items listedbelow be inspected by a qualified servicetechnician every year.a. Water temperature controlsb. Pilot safety system.c. Automatic gas valves.d. Flow sensing safety devices.e. Vent dampers and power venters.f. Venting system.

NOTE: The Warranty does not cover damage causedby lack of required maintenance, lack of water flow, orimproper operating practices.12. Fouling on the external surfaces of the heat

exchanger is caused by incomplete combustion,and is a sign of venting and/or combustion airproblems. The heat exchanger can be inspectedby using a flashlight and placing a mirror underthe burners. An alternate method is to remove theventing and top panel to inspect the exchangerfrom above. The vent system should be inspectedat the same time. If cleaning is required:a. Shut off all power to the boiler.b. Remove the draft hood, venting top, flue

collector, and heat exchanger baffles.c. Remove the burners by lifting them off the

orifices and pulling them out of the boiler.d. Use a hand-operated spray bottle filled with

water, and a wire brush to clean soot andloose scale from the underside of the heatexchanger. DO NOT USE COMPRESSEDAIR, HIGH PRESSURE WATER OR AGARDEN HOSE.

e. Clean any fallen debris from the bottom ofthe unit.

f. Check to make sure the burner ports andpilot assembly are free of debris beforereturning the burners to their originalposition.

g. Reassemble the boiler in reverse order,making sure to replace the heat exchangerbaffles.

8.2 Boiler Components and Their Operation

1. Gas Valve / Regulator - The gas valve controlsgas flow into the manifold. It provides flow onlywhen the temperature control requires heat andonly if all safety controls enable operation. It isalso a positive pressure regulator. It regulates thegas pressure in the manifold to specificationsaddressed earlier in this manual. This isnecessary for proper operation of the burnersystem. JVS 100-225 Only - Gas Valve /Regulator has two output stages controlled bytwo-stage temperature control.

Figure 14. 1) JVS Pilot; 2) JVH Pilot;3) Main Burner Flame Pattern; 4) JVT Pilot.


CautionTwo-stage Operating Control (JV100-225 ONLY):Factory setting is 140°F (60°C). This setting iscorrect for most hydronic heating applications.Adjustments to this setting must be made by anauthorized service technician.

2. Two-stage Temperature Control - JVS 100-225 are equipped with a two-stage temperaturecontrol which senses inlet water temperature. Itis used to control the firing rate of the mainburners, cycling the gas valve between low, highand off.

3A. Ignition Control, JVS - When the thermostatcalls for heat and all limits are satisfied a pilottrial for ignition is initiated. If pilot is notestablished a 5 minute minimum delay isimplemented prior to the next trial for ignition.This cycle repeats until pilot is established or thesystem is shut down manually.JVS 100-225 only - Once pilot is established themain valve is enabled and controlled by the two-stage temperature control.JVS 50-75 only - Once pilot is established themain valve will open until the limit circuit opens.

3B. JVT Flame Control - The standing pilot JVTmodels rely on a flame sensor on the gas valve.When the thermostat calls for heat and adequatepilot flame is sensed, the gas valve will open.The valve will remain open until the limit circuitopens.

4. Pilot AssemblyJVS - The pilot assembly utilizes an electrodethat is used to generate spark to ignite the pilotflame as well as sense flame presence.JVT - The JVT pilot is lit manually and sensespilot flame via a thermocouple which generates asignal that allows the gas valve to open.

5. Hi-Limit Switch: Factory setting is 190°F(88°C). This setting is correct for normaloperations, and should only be changed by anauthorized service technician. Under nocircumstances should the setting exceed 220°F(104°C).

6. Blocked Vent Switch - JVS and JVT boilers areequipped with a manual reset blocked ventswitch designed to shut the boiler down in theevent the vent is completely blocked. The switchis located in the draft diverter opening on the rearof the boiler.

7. Rollout Switch - JVS and JVT boilers areequipped with a manual reset rollout switchdesigned to shut the boiler down in the event aflame rollout situation occurs causing excessivetemperatures. The switch is located on the burnercover.

SECTION 9.Troubleshooting

9.1 General Boiler TroubleshootingTable 8 lists some of the more common

problems, causes and solutions encountered whenrunning the boiler. Most problems occur when theboiler is being started for the first time afterinstallation. Careful installation and maintenance willhelp ensure years of trouble free use from your LaarsMini-Therm II boiler.

WARNINGSERVICING SAFETYSome of the servicing procedures for the LaarsMini-Therm II JVS and JVT boilers are hazardousbecause they involve fuel gas, electricity, movingparts and procedures which require testing ortemporary bypass of safety controls. For thisreason, the boiler must be serviced only by aqualified professional service technician.

IMPROPER SERVICE HAZARDThe Mini-Therm II JVS and JVT boilers incorporateunique design features. Incorrect service of thisheater can result in personal injury or damage toproperty. To avoid such hazards, the boiler must beserviced only by a qualified professional servicetechnician.

AVERTISSEMENTPRÉCAUTIONS LORS DES RÉPARTATIONS ETDE L’ENTRETIENCertaines procédures d’entretien et de réparationdes appareils de chauffage à faibles émissionsprésentent des changers, car elles mettent en jeudes gaz combustibles, des composants électriques,des pièces mobiles et des procédures quinécessitent des mises à l’essai ou la dérivationtemporaire des commandes de sécurité. Pour cetteraison, l’appareil de chauffage doit être entretenu etréparé uniquement par un technicien professionnelqualifié

DANGERS D’UN ENTRETIEN INADÉQUATLes appareils de chauffage à faibles émissionscomportent des caractéristiques techniquesuniques. Une réparation ou un entretien inadéquatpeut entraîner des blessures corporelles ou desdommages à la propriété. Pour cette raison,l’appareil de chauffage doit être entretenu et réparéuniquement par un technicien professionnelqualifié.


Table 8. Troubleshooting Guide.

# Symptom Cause Remedy

1. Pump not A. No power A. Check circuit breakers and power source.operating B. Pump defective B. Replace.

C. Incorrectly wired C.Recheck wiring diagrams.

2. Pilot outage A. Inlet gas pressure too low A. Consult gas utility company. Inlet gas pressure to boilershould be 5.5" to 10.5" water column on natural gas. 0.0" to

13.0" on propane gas.B. Inlet gas pressure too high causing

an unstable blowing pilot B. Pressure should be regulated within limits shown above.C.Weak or defective thermocouple C.Replace thermocouple.D.Damaged pilot or thermocouple D.Replace.E. Dirty pilot E. Blow dust or lint out of pilot.F. Plugged or undersized pilot orifice F. Clean or replace pilot orifice.

3. Flame roll-out A. Blocked flue A. Remove blockage.on start-up B. Pilot out of position (delayed ignition) B. Correct pilot position.

C.Blocked heat exchanger or flue C.Clean and correct as necessary.D.Refractory tile out of place D.Correct or replace tile as necessary.E. Altered draft diverter E. Install factory-provided draft diverter.

4. Spillage at A. Cold chimney A. Allow boiler to operate 5 minutes to create draft action.draft hood B. Vent pipe pitches down to chimney B. Reinstall vent pipe to pitch up from boiler to chimney.

C.Blocked chimney C.Remove blockage.D.Draft hood altered D. Install factory-provided draft diverter.E. Pre-fabricated chimney with incorrect cap E. Install U.L. listed vent cap.

5. Flame has A. Low primary air A. Correct manifold pressure according to rating plate. Correctlazy yellow tip orifice size if necessary (see parts list). Clean burner ports if

dirty. Verify correct fuel type.

6. Not enough heat A. Inadequate gas supply A. Gas meter too small. Gas line from meter to boiler too small.B. Low manifold gas pressure B. Gas pressure on boiler manifold (at normal firing rate)

should be adjusted to 4.0"W.C. natural gas, 9.0"W.C.propane.

C.Boiler size inadequate C.Replace with boiler of higher input.D.JVS 100-225 only - Boiler not going to

high fire. D.Check operation and setting of two-stage operating control.

7. Pump noisy A. Air in volute A. Bleed air from volute. Check pump alignment.B. Worn coupling or bearings B. Replace worn parts.

8. Boiler pounding A. Too low water flow through boiler A. Check temperature rise between inlet and outlet boiler piping.or knocking 15°F to 25°F temperature rise is recommended. If temperature

rise is over 25°F, increase pipe size or pump capacity orlocate obstruction. Check for stuck closed zone valves.Check for zone pumps not operating. Check for closed valvein system.

9. Boiler condensing A. Low water temperature A. Flue product moisture will condense at the start-up until theboiler water temperature reaches the normal operatingconditions.

10. Pump cavitates A. Defective fill valves or pressure regulator A. Replace.or low water B. Oversized expansion tank B. Replace.pressure at boiler C.Expansion tank piped incorrectly C.Repipe expansion tank to suction size of pump.gauge or bubblesin system at hightemperature

11. Pressure relief A. Water-logged expansion tank A. Drain 2/3 of the water from the expansion tank.valve opens

12. Pilot is lit but main A. Gas valve not at "on" position (JVT) A. Turn knob to "on" position.burners will not B. Boiler off on hi-limit control B. Check for low water flow or hi-limit setting.come on C.Boiler incorrectly wired C.On single or multiple zone systems with zone valves, room

thermostat should be wired to R & W terminals. For multiplezone systems with zone pumps, thermostats for extra zonesshould be wired to R & A terminals.

D.Boiler off on blocked vent switch D.Remedy as in symptom #4. Reset the manual reset switch.E. Boiler off on flame roll-out switch E. Remedy as in symptom #3. Reset the manual reset switch.F. Broken wire in thermostat circuit

or defective thermostat F. Check continuity through thermostat circuit with wiresdisconnected from R & W.

G.JVS 100-225 Only - Two-stage operatingcontrol not functioning or loose contact. G.Check continuity and operation through two-stage operating

control.

13. Boiler short cycles A. Heat anticipator in room thermostatset too low A. Increase setting (0.8 - 1.0 is usually satisfactory).

B. Low water flow through boiler B. Increase size of pump or increase piping size.C.Hi-limit switch may be set too low C. Increase setting to at least 20°F over outlet water temperature.

9.2 Troubleshooting Guide


9.3 Troubleshooting Honeywell S8600 Intermittent Pilot System

Some boilers may be equipped with an ignition module that shuts off pilot gas if pilot fails to light.To reset, interrupt power to heater

Note: Before troubleshooting, familiarize yourself with the start-up andcheckout procedure.

Check line voltage power, low voltage transformer, hi- limit switch,thermostat (controller) and wiring.

Pull ignition lead and check spark at module.Spark okay?

• Check ignition cable ground wiring, ceramic insulator and gap, and correct.• Check boot of the ignition cable for signs of melting or buckling. Take

protective action to shield cable and boot from excessive temperatures.

• Check that all manual gas valves are open, supply tubing and pressuresare good, and pilot burner orifice is not blocked.

• Check electrical connections between module and pilot operator on gascontrol.

• Check for 24 Vac across PV-MV/PV terminals on module. If voltage isokay, replace gas valve; if not, replace module.

• Check continuity of ignition cable and ground wire.• Clean flame rod.• Check electrical connections between flame rod and module.• Check for cracked ceramic flame rod insulator.• Check that pilot flame covers flame rod and is steady and blue.• Adjust pilot flame.• If problem persists, replace module.

• Check for 24 Vac across MV-MV/PV terminals. If no voltage, replacemodule.

• Check electrical connections between module and gas valve. If okay,replace gas valve.

• Check continuity of ignition cable and ground wire.Note: If ground is poor or erratic, shutdowns may occur occasionally eventhough operation is normal at the time of checkout.

• Check that pilot flame covers flame rod and is steady and blue.• If checks are okay, replace module.

• Check for proper thermostat (controller) operation.• Remove MV lead at module; if valve closes, recheck temperature

controller and wiring; if not, replace gas valve.

Repeat procedure until trouble-free operation is obtained.

Start

Turn off gas supply.Turn thermostat

(controller) to call forheat.

Power to module(24V nominal).

Spark across igniter/sensor gap.

Turn gas supply on.Pilot burner lights?

Spark stops when pilotis lit?

Main burner lights?

System runs until callfor heat ends?

Call for heat ends.System shuts off?

Troubleshooting ends

YES

NO

YES

NO

YES

NO

YES

NO

YES

NO

YES

NO

YES

NO

YES


9.4 Electrical Troubleshooting1. Remove the control box cover on the front of the

boiler.2. Verify that 115V is reaching the boiler by testing

across the black wire on the pump relay and thewhite wire on the transformer.

3. Verify 24V transformer output by placing themeter leads on the yellow and red wires. If 24Vis not evident, replace the transformer. Performthe following series of tests with one meter leadattached to the yellow wire on the transformer.

4. Place the second lead on the "W" connection onthe terminal board. Turn the wall thermostat highenough to call for heat. If the meter fails toregister 24V, the thermostat or its circuit may bedefective.

5. Make sure thermostat is set high enough to callfor heat. Place second lead on the "A"connection on the terminal board. If voltage isevident, skip to step 6. If no voltage, test thecircuit between the red wire on the transformerand terminal 4 on the pump relay; from terminal6 on the pump relay and the "A" connection onthe terminal board; and from the purple wireterminal on the pump relay to the "W"connection on the terminal board. If no output isfound, theconnections or the pump relay could be defective.

6. Place the second lead on the orange wireterminal on the hi-limit switch. If no voltageacross the switch, check for defective hi-limit,open circuit due to excessive water temperature,or a low temperature setting.

7. Place the second lead on the orange wireterminal on the blocked vent safety switch. Ifvoltage is present, the vent damper is open. Ifvoltage isn't present, connections or the ventdamper could be defective.

8. Verify the voltage across the blocked vent androll-out safety switches.

9. On JVT boilers, test for voltage at the "TH"terminal on the gas valve. If none is found,follow steps 1 through 8.

10. If it is determined that there is voltage to the gasvalve, the pilot is lit and the thermocouple isproperly positioned, and the thermostat is sethigh enough to call for heat, the gas valve or thepilot thermocouple may be defective

11. There are two tests necessary to make sure theproblem is not in the pilot thermocouple. Thefirst test can be performed by unscrewing thecompression fitting on the gas valve, and placingone millivoltmeter lead on the center post of thetube and the other lead on the copper tubing. Ifthe meter shows a reading of approximately 30millivolts, proceed to the second test. If it

doesn't, replace the pilot thermocouple. Thesecond test requires the use of a MillivoltReading Adapter to test the thermocouple underload. Once again, remove the pilot thermocouplecompression fitting from the gas valve. Replaceit with a Millivolt Reading Adapter, and screwthe thermocouple fitting into the end of theadapter. Attach one lead from the millivoltmeterto either side of the adapter and the other lead toground. Light the pilot and set the wallthermostat high enough to call for heat. With theboiler firing, take a millivolt reading. It shouldbe in the 15 millivolt range. If it isn't, replace thepilot thermocouple.

CautionLabel all wires prior to disconnection when servicingcontrols. Wiring errors can cause improper anddangerous operation. Verify proper operation afterservicing.

ATTENTIONAu moment de l’entretien des commandes, mettezdes étiquettes sur tous les fils avant de lesdébrancher. Des erreurs de câblage peuventcauser un fonctionnement inadéquat et dangereux.Vérifier que tout fonctionne bien après votreentretien.

SECTION 10.Glossary

10.1Glossary of TermsAir VentAnother device used to purge air from the circuit.Should be located at the highest point in the circuit.

BranchThe section(s) of supply and return piping, includingthe heat distribution units (see below), connecteddirectly to the trunk. Also referred to as a "zone."

By-passA section of pipe (including an adjustable valve) thatdiverts part of the water flow from the boiler outlet tothe inlet, adjusted to maintain minimum flowrequirement (GPM) or inlet water temperature.

CircuitEntire water circulation piping, beginning and endingat the boiler (Series Loop System).

Expansion Tank (Compression Tank)Installed in the circuit to accommodate excess waterproduced by heat expansion, and to maintain thesystem pressure.


Heat Distribution UnitsTransfers heat from the water supplied by the boiler tothe area to be heated through the use of baseboard,convector, radiator, finned tube. Also known as"radiation."

Isolation ValveUsed to isolate the boiler from the circuit. It minimizesthe amount of water drained from the system.

Primary-Secondary PipingTwo or more interconnecting circulating loops, eachwith its own pump.

Reverse-return PipingBalanced, equal flow (first in, last out) piping. Utilizedwith multiple boilers and/or radiation. Applied withsingle system pumps, or primary-secondary pumps.

Side Wall Power VenterThis Laars accessory allows the boiler exhaust to berouted horizontally through an adjoining outside wall,rather than gravity venting with a chimney or stackwhen local codes allow.

System Purge ValveA device used to purge air from the circuit. Should belocated as close as possible to the cold water feed,but not immediately after the cold water feed.

TrunkThe section of piping which connects the boiler returnand supply with the branch(es). Also known as a"main" or "header." Should be same size as boilerinlet/outlet connections.

Vent Damper (optional in Canada)Standard on JV boilers. This energy-saving deviceprevents heated air from exiting the open vent whenthe boiler is not operating.

Zone PumpCirculators installed in branch piping that divert hotwater coming from the boiler into various areas(zones) of a building.

Zone ValveDiverts hot water from the boiler into various areas(zones) of a building.

SECTION 11.Replacement Parts

11.1Ordering InformationTo order or purchase parts for the Laars Mini-

Therm II JVS or JVT boiler, contact your nearestLaars Representative. If you need assistance in findinga local dealer or distributor, contact the TechnicalService Department.

NOTE: To supply the correct part it is important thatyou state the model number, serial number and typeof gas when applicable. This information is on therating plate on the heater.

11.2Parts ListThe following three pages contain a parts list and

a general exploded view to aid in parts identification.Please refer to these pages when ordering parts foryour JVS or JVT boiler.

LAARS Heating SystemsD

escr

iptio

n M

odel

, Siz

eJV

S-50

JVT-

50JV

S-75

JVT-

75JV

S-10

0JV

T-10

0JV

S-12

5JV

T-12

5JV

S-16

0JV

T-16

0JV

S-22

5JV

T-22

5

Pilo

t Gas

Sys

tem

Pilo

t Ass

y (N

at.)

W00

3060

0W

0040

900

W00

3060

0W

0040

900

W00

3060

0W

0040

900

W00

3060

0W

0040

900

W00

3060

0W

0040

900

W00

3060

0W

0040

900

Pilo

t Ass

y (L

P)

W00

3960

0W

0040

901

W00

3960

0W

0040

901

W00

3960

0W

0040

901

W00

3960

0W

0040

901

W00

3960

0W

0040

901

W00

3960

0W

0040

901

Ther

moc

oupl

eW

0036

500

W00

3650

0W

0036

500

W00

3650

0W

0036

500

W00

3650

0

Mai

n G

as S

yste

mB

urne

r w/P

ilot B

rack

etL0

0565

00L0

0565

00L0

0565

00L0

0565

00L0

0565

00L0

0565

00L0

0565

00L0

0565

00L0

0565

00L0

0565

00L0

0565

00L0

0565

00B

urne

r, M

ain

L005

2500

L005

2500

L005

2500

L005

2500

L005

2500

L005

2500

L005

2500

L005

2500

L005

2500

L005

2500

L005

2500

L005

2500

Bur

ner/A

ir S

hutte

rL0

0559

00L0

0559

00L0

0559

00L0

0559

00L0

0559

00L0

0559

00L0

0559

00L0

0559

00L0

0559

00L0

0559

00L0

0559

00L0

0559

00G

as V

alve

,H

W V

R83

04 (N

at.)

V00

7740

0V

0077

400

V00

7900

0V

0079

000

V00

7900

0V

0079

000

Gas

Val

ve,

HW

VR

8300

(Nat

.)V

2002

000

V20

0200

0V

2002

000

V20

0200

0V

2002

000

V20

0200

0G

as V

alve

,H

W V

R83

04 (L

P)

V00

7750

0V

0077

500

V00

7910

0V

0079

100

V00

7910

0V

0079

100

Gas

Val

ve,

HW

VR

8300

(LP

)V

2002

100

V20

0210

0V

2002

100

V20

0210

0V

2002

100

V20

0210

0G

as O

rific

e(N

at. 0

-200

0ft)

L003

2200

L003

2200

L003

2200

L003

2200

L003

2200

L003

2200

L003

2200

L003

2200

L003

2600

L003

2600

L005

0700

L005

0700

Gas

Orif

ice

(LP

0-5

000f

t)L0

0329

00L0

0329

00L0

0329

00L0

0329

00L0

0329

00L0

0329

00L0

0329

00L0

0329

00L0

0329

00L0

0329

00L0

0329

00L0

0329

00G

as M

anifo

ldL0

0526

01L0

0526

01L0

0526

02L0

0526

02L0

0526

03L0

0526

03L0

0526

04L0

0526

04L0

0526

05L0

0526

05L0

0526

06L0

0526

06

Elec

tric

al S

yste

mR

elay

, DP

NO

E00

8840

0E

0088

400

E00

8840

0E

0088

400

E00

8840

0E

0088

400

E00

8840

0E

0088

400

E00

8840

0E

0088

400

E00

8840

0E

0088

400

Tran

sfor

mer

115

/24V

(40V

A)

E00

8610

0E

0086

100

E00

8610

0E

0086

100

E00

8610

0E

0086

100

E00

8610

0E

0086

100

E00

8610

0E

0086

100

E00

8610

0E

0086

100

Igni

tion

Con

trol

E21

0280

0E

2102

800

E21

0280

0E

2102

800

E21

0280

0E

2102

800

Lim

it S

witc

hE

0098

700

E00

9870

0E

0098

700

E00

9870

0E

0098

700

E00

9870

0E

0098

700

E00

9870

0E

0098

700

E00

9870

0E

0098

700

E00

9870

0Tw

o-S

tage

Ope

ratin

g C

ontro

lE

0093

200

E00

9320

0E

0093

200

E00

9320

0C

ontro

l Pan

el W

iring

Har

ness

2040

6501

2040

6501

2040

6501

2040

6501

2040

6501

2040

6501

2040

6501

2040

6501

2040

6501

2040

6501

2040

6501

2040

6501

Pow

er V

ente

r Jum

per

2003

6700

2003

6700

2003

6700

2003

6700

2003

6700

2003

6700

2003

6700

2003

6700

2003

6700

2003

6700

2003

6700

2003

6700

Term

inal

Stri

pE

0098

500

E00

9850

0E

0098

500

E00

9850

0E

0098

500

E00

9850

0E

0098

500

E00

9850

0E

0098

500

E00

9850

0E

0098

500

E00

9850

0H

i-Ten

sion

Lea

d10

4495

1410

4495

1410

4495

1410

4495

1410

4495

1510

4495

16B

lock

ed V

ent S

afet

y S

witc

hE

0121

000

E01

2100

0E

0121

000

E01

2100

0E

0121

000

E01

2100

0E

0121

000

E01

2100

0E

0121

000

E01

2100

0E

0121

000

E01

2100

0R

oll-o

ut S

afet

y S

witc

hE

2103

200

E21

0320

0E

2103

200

E21

0320

0E

2103

200

E21

0320

0E

2103

200

E21

0320

0E

2103

200

E21

0320

0E

2103

200

E21

0320

0Fu

se, 2

am

pE

2043

600

E20

4360

0E

2043

600

E20

4360

0E

2043

600

E20

4360

0E

2043

600

E20

4360

0E

2043

600

E20

4360

0E

2043

600

E20

4360

0


Des

crip

tion

Mod

el, S

ize

JVS-

50JV

T-50

JVS-

75JV

T-75

JVS-

100

JVT-

100

JVS-

125

JVT-

125

JVS-

160

JVT-

160

JVS-

225

JVT-

225

Wat

er S

yste

mH

eat E

xcha

nger

1104

6001

1104

6001

1104

6002

1104

6002

1104

6003

1104

6003

1104

6004

1104

6004

1104

6005

1104

6005

1104

6006

1104

6006

Tem

pera

ture

/Pre

ssur

e G

auge

A00

0010

0A

0000

100

A00

0010

0A

0000

100

A00

0010

0A

0000

100

A00

0010

0A

0000

100

A00

0010

0A

0000

100

A00

0010

0A

0000

100

Pre

ssur

e R

elie

f Val

ve, 3

0PS

IA

0069

000

A00

6900

0A

0069

000

A00

6900

0A

0069

000

A00

6900

0A

0069

000

A00

6900

0A

0069

000

A00

6900

0A

0069

000

A00

6900

0W

ell,

Imm

ersi

onE

2058

300

E20

5830

0E

2058

300

E20

5830

0E

2058

300

E20

5830

0E

2058

300

E20

5830

0E

2058

300

E20

5830

0E

2058

300

E20

5830

0D

rain

Val

ve 1

/2" N

PT

P00

6660

0P

0066

600

P00

6660

0P

0066

600

P00

6660

0P

0066

600

P00

6660

0P

0066

600

P00

6660

0P

0066

600

P00

6660

0P

0066

600

Jack

et a

nd F

ire B

ox C

ompo

nent

sD

raft

Div

erte

r11

0201

0111

0201

0111

0201

0211

0201

0211

0201

0311

0201

0311

0201

0411

0201

0411

0201

0511

0201

0511

0201

0611

0201

06R

ear P

anel

1102

0201

1102

0201

1102

0201

1102

0201

1102

0203

1102

0203

1102

0203

1102

0203

1102

0205

1102

0205

1102

0206

1102

0206

Jack

et11

0193

0111

0193

0111

0193

0111

0193

0111

0193

0311

0193

0311

0193

0311

0193

0311

0193

0511

0193

0511

0193

0611

0193

06To

p11

0194

0111

0194

0111

0194

0211

0194

0211

0194

0311

0194

0311

0194

0411

0194

0411

0194

0511

0194

0511

0194

0611

0194

06G

ap C

losu

re11

0476

0311

0476

0311

0476

0411

0476

0411

0476

0311

0476

0311

0476

0411

0476

0411

0476

0411

0476

0411

0476

0611

0476

06Fl

ue C

olle

ctor

2003

4901

2003

4901

2003

4902

2003

4902

2003

4903

2003

4903

2003

4904

2003

4904

2003

4905

2003

4905

2003

4906

2003

4906

Acc

ess

Pan

el H

X, (

L&R

)10

5359

0010

5359

0010

5359

0010

5359

0010

5359

0010

5359

0010

5359

0010

5359

0010

5359

0010

5359

0010

5359

0010

5359

00B

ase,

Con

trol B

ox20

0868

0020

0868

0020

0868

0020

0868

0011

0457

0011

0457

0011

0457

0011

0457

0011

0457

0011

0457

0011

0457

0011

0457

00C

over

, Con

trol B

ox20

0868

0020

0868

0020

0868

0020

0868

0011

0458

0011

0458

0011

0458

0011

0458

0011

0458

0011

0458

0011

0458

0011

0458

00B

urne

r Cov

er10

5006

0110

5006

0110

5006

0110

5006

0110

5006

0210

5006

0210

5006

0210

5006

0210

4941

0510

4941

0510

4941

0610

4941

06H

eat E

xcha

nger

Baf

fle10

4853

0110

4853

0110

4853

0810

4853

0810

4853

0910

4853

0910

4853

1110

4853

1110

4853

1010

4853

1010

4853

0610

4853

06Ti

le C

over

1046

9501

1046

9501

1046

9502

1046

9502

1046

9503

1046

9503

1046

9504

1046

9504

1046

9505

1046

9505

1046

9506

1046

9506

Ref

ract

ory,

Fro

ntT0

0220

01T0

0220

01T0

0220

02T0

0220

02T0

0220

03T0

0220

03T0

0220

04T0

0220

04T0

0220

05T0

0220

05T0

0220

06T0

0220

06R

efra

ctor

y, R

ear

T002

1701

T002

1701

T002

1702

T002

1702

T002

1703

T002

1703

T002

1704

T002

1704

T002

1705

T002

1705

T002

1706

T002

1706

Insu

latio

n, F

iber

glas

sT0

0273

00T0

0273

00T0

0273

00T0

0273

00T0

0273

00T0

0273

00T0

0273

00T0

0273

00T0

0273

00T0

0273

00T0

0273

00T0

0273

00B

ase

Ass

embl

y10

4671

0110

4671

0110

4671

0210

4671

0210

4671

0310

4671

0310

4671

0410

4671

0410

4671

0510

4671

0510

4671

0610

4671

06C

ombu

stib

le B

ase

1046

6701

1046

6701

1046

6701

1046

6701

1046

6702

1046

6702

1046

6702

1046

6702

1046

6703

1046

6703

1046

6704

1046

6704

Vent

Dam

per C

ompo

nent

sA

utom

atic

Ven

t Dam

per

Ass

y., E

ffika

l PC

E20

7150

1E

2071

501

E20

7150

2E

2071

502

E20

7150

2E

2071

502

E20

7150

3E

2071

503

E20

7150

3E

2071

503

E20

7150

4E

2071

504

Dam

per C

onne

ctio

n H

arne

ssE

0099

100

E00

9910

0E

0099

100

E00

9910

0E

0099

100

E00

9910

0E

0099

101

E00

9910

1E

0099

101

E00

9910

1E

0099

101

E00

9910

1


Figure 15. Parts Identification.

11.3Exploded View

Vent Damper

Draft Diverter

Top

Rear PanelBurner with Pilot BracketPilot AssemblyGas Manifold

BaseAssembly

Refractory,Rear

Refractory, Front

Gap Closure

HX AccessPanel

Heat Exchanger

Flue Collector

�

��

�

1-1/4” Hold1-1/8” Hold1-1/4” Hold1-7/8” Hold

�

��

AquastatBulb

Cover,ControlBox

Temperature/Pressure Gauge

Jacket, One PieceWraparound

A

B C

A - Inlet PipeB - 4-1/2”x3/4” PipeC - Outlet Pipe

Gas Valve

Flame Roll-OutSafety Switch

Burner Cover

Tile Cover

DrainValve

1/2" Coupling(Model 50 and 100)P0005200

½” CloseNipple(Model 50and 100)

OrificesPilot Gas Tube

TerminalStrip

Vent Damper Connection Harness

PressureRelief Valve

�B

Transformer

Pump Relay

HighLimit

BlockedVentSafetySwitch

Immersion Well

2-Stage Operating Control (100-225)

H00

7140

0Y

A subsidiary of BRADFORD WHITE Corporation

800.900.9276 • Fax 800.559.1583 (Customer Service, Service Advisors)20 Industrial Way, Rochester, NH 03867 • 603.335.6300 • Fax 603.335.33551869 Sismet Road, Mississauga, Ontario, Canada L4W 1W8 • 905.238.0100 • Fax 905.366.0130www.Laars.com Litho in U.S.A. © Laars Heating Systems 0805 Document 1025Y

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