american standard system charging manual

S y s t e m C h a r g i n gS y s t e m C h a r g i n g

• Heating and Cooling

• Capillary Tube Systems

• Thermostatic ExpansionValve Systems

• Charging by Weight

• Heating and Cooling

• Capillary Tube Systems

• Thermostatic ExpansionValve Systems

• Charging by Weight© American Standard Inc. 2001© American Standard Inc. 2001

Preface

The purpose of this publication is to provide service technicians with the general knowledgenecessary to properly charge a Heat Pump system or an Air Conditioning system. Thismanual outlines, in detail, recommended charging procedures to be followed on all capillarytube and expansion valve systems.

Before any of the procedures outlined in this manual can be initiated the service technicianmust have all the necessary tools as listed under equipment on page 4.

In addition to tools proper airflow must be verified prior to any attempt to charge a system.The system should be checked to confirm that all air filters are clean, that the blowerassembly and coil are free of dirt and that the duct system is adequate. If proper airflow isnot available all associated problems must be corrected prior to attempting any chargingprocedure.

Cooling performance can be checked when outdoor temperature is above 75°.Heating performance can be checked when the outdoor temperature is below 60°.

Note: This publication is general in nature and is intended forINSTRUCTIONAL PURPOSES ONLY. It is not to be used forequipment selection, application, installation, or specific serviceprocedures.

Section 608, paragraph C of the Clean Air Act of 1990 states:

Effective July 1, 1992, it shall be unlawful for any person, in the course of maintaining,servicing, repairing, or disposing of an air conditioning system, to knowingly vent or releaseany CFC or HCFC refrigerant. Minimal releases (air purges of refrigerant hoses) associatedwith good faith attempts to recapture or recycle are exempt from the ban on venting.

The Clean Air Act has provisions for significant fines and/or imprisonment for non-compliance. These fines could range from $5,000 to $25,000 per day.

Table Of Contents

Refrigerant System Charging .................................................................................................................................... 2

Service Tools — Equipment ...................................................................................................................................... 2

Metering Devices ....................................................................................................................................................... 3

Cooling Systems ........................................................................................................................................................ 4

Heat Pump Systems .................................................................................................................................................. 5

Equipment Pressure Taps (General) ......................................................................................................................... 6

Charging Capillary Tube/FCCV – Cooling Mode Only .............................................................................................. 7

Example Slide Rule Calculation ................................................................................................................................ 8

Performance – Cooling Mode.................................................................................................................................... 9

Charging and Performance – Cooling Mode ............................................................................................................ 10

Charging By Subcooling – Cooling Mode................................................................................................................. 11

Performance – Heating Mode.................................................................................................................................... 12

Charging – Heating Mode .......................................................................................................................................... 13

Charging By Weight ................................................................................................................................................... 15

Calibrating Pressure Gauges ..................................................................................................................................... 16

Refrigerant 410A

Background ............................................................................................................................................................ 17

Characteristics ........................................................................................................................................................ 17

Refrigerant Safety ...................................................................................................................................................... 18

Application Notes ...................................................................................................................................................... 19

System Charging Using R410A ................................................................................................................................ 20

R-410A Temperature and Pressure Chart ................................................................................................................. 21

Subcooling Table ....................................................................................................................................................... 22

R-410A Split Cooling Units Only ............................................................................................................................... 24

R-410A Split Heat Pump Units Only ......................................................................................................................... 25

R-410A Charging and Performance – Cooling Mode............................................................................................... 26

R-410A Charging – Heating Mode – R-410A............................................................................................................. 27

IMPORTANT

These procedures should be followed at initial start-up and at anytime the power has been removed for12 hours or more.

To prevent compressor damage which may result from the presence of LIQUID refrigerant in thecrankcase:

1. Make certain the room thermostat is in “off” position. (The compressor is not to operate.)

2. Apply power by closing the system disconnect switch. This energizes the compressor heater whichevaporates the liquid refrigerant in the crankcase. Allow 30 minutes for each pound of refrigerant inthe system as noted on the unit nameplate.

3. After proper elapsed time the thermostat may be set to operate the compressor.

4. Except as required for safety while servicing – DO NOT OPEN SYSTEM DISCONNECT SWITCH.

1

Refrigerant System Charging

Refrigerant charging is one of the most importantand probably least understood service procedurespracticed in the air conditioning industry. Improperlycharged systems lead to inefficient operation andpremature equipment failure. The graph belowillustrates a typical package cooling system charge

being varied from 50% undercharge to 37.5%overcharge. Airflow and temperatures were heldconstant at ARI standard conditions as the charge wasvaried. Note the change in capacity, power input andEER as each pound of refrigerant was added above50% undercharge.

LIQUIDSUBCOOLING

50%

4#

62.5

5#

75

6#

87.5

7#

100%

8#

112.5

9#

125

10#

137.5%

11#

EVAP. SUCT.SUPERHEAT

SUCTIONPRESSURE

EER

POWERINPUT

COOLINGCAPACITY

KW

BT

UH

BT

U/W

AT

T-H

RP

SIG

Tem

pera

ture

-°F

DISCHARGEPRESSURE

Refrigerant ChargeCorrect Charge

• Optimum capacity

• Highest possible EER

• Longest equipment life

Undercharge

• Capacity decreases

• Power input decreases but not in proportion tocapacity

• EER goes down

• Equipment life is shortened

Overcharge

• Capacity decreases as more charge is added beyondthe optimized capacity

• Power input increases

• EER decreases

• Equipment life is shortened

EER =

COP =

BTU Output

Power Input

BTU Output

BTU Input

Service Tools — Equipment

The Service Tools needed to PROPERLY charge a refrigeration system includes:

1. Manifold Gauges

2. Electronic Temperature Analyzer (Temperature measurements should be made with a good quality electronictemperature tester such as a Robinair 12860, Annie A-8, Electro-medic M-99, or equivalent.)

3. Sling Psychrometer

4. Refrigerant- 22 (Mono-chlorodiflouromethane)

5. Approved refrigerant recovery system and holding tank.

Note:1. The package cooling system used to develop the

above information utilized a TXV refrigerantmetering device.

2

2. Field conditions different from ARI conditions (95° dboutdoor air, 80° db-67° wb return air) will yield resultsthat vary from the graphs in this example.

Metering Devices

We use various types of refrigerant metering devices inair conditioning and heat pump systems. The coolingunits we will discuss are equipped with Flow ControlCheck Valves (FCCV), see diagram below left, CapillaryTubes, Bleed-Type Thermostatic Expansion Valves(TXV-B) and Non-Bleed Thermostatic Expansion Valves(TXV-NB), see diagram below right. Current heat pumpunits which we will cover are equipped with Bleed andNon-Bleed TXV in outdoor sections with everythingbut Capillary Tubes on indoor coils. The CCBA andCUBA coils have a fixed flow control device for cooling-only applications.

The FCCV Flow Control is used on TXA-C and TXC-Cuniversal convertible coils. This metering device isapplied to these coils for cooling and heat pump appli-cations with 10 and 11 SEER products respectively.Package products may either use a FCCV or CapillaryTube metering devices. (FCCV coils are not anapproved combination with a 5 ton 12 SEER or any14 SEER outdoor units. These units can easily be over-charged with this type of metering device because thelarge volume of refrigerant in the system may notshow an increase in head pressure. Only TVX coilsshould be used.)

Care should be taken that the proper size FCCV ismatched to the outdoor unit to insure that the correctvolume of refrigerant is flowing through the system(approx. 3 lbs/ton/minute). The orifice size of the FCCVis marked on the side of the metering device. TXA-Cand TXC-C coils are shipped with the orifice size thatmatches the most commonly used outdoor unit withthat particular coil combination. That size is indicatedon the tag on the coil connection end. Correct orificesize is dependent on the outdoor unit model. Theproper orifice for the indoor unit is in a small bagattached to the outdoor unit. (Orifices shipped withindoor coils may or may not be correct for the outdoor

unit, so the installer must verify size at the time of in-stallation.) Refer to Service Facts which also showsthe proper size and type of metering device for theapplication.

TXC-E high efficiency coils are equipped with Bleed-Type TXVs for refrigerant control. The diaphragm onthe TXV opens or closes the valve orifice to maintaina preset superheat and control refrigerant flow as loadconditions on the evaporator change. When the com-pressor shuts off, refrigerant is able to bleed betweenthe high pressure side upstream of the TXVand the low pressure downstream of the TXV; thesystem will equalize within 3-5 minutes. Also, thesecoils have a larger internal volume in order to supportadditional charge and provide for higher efficiencies.These coils are designed to be matched with 12 SEERoutdoor units for higher SEER requirements. Thesecoils can also be mated to 10 and 11 SEER units.

The TXC-S variable speed coils are equipped withNon-Bleed TXVs (TXV-NB). These coils do not equalizeor bleed through the valve orifice which helps to pre-vent refrigerant from migrating back to the compressorafter system shutdown. These coils should only beapplied to outdoor products that are equipped withquick start components because of the pressure differ-ential during system start up. Scroll compressor unitdoes not require a quick start component. Variablespeed coils are mated with 12 and 14 SEER productsfor high efficiency.

Because today’s high efficiency systems requireadditional refrigerant volume to produce the neededcapacity and efficiency, it is important that systems beinstalled with the proper size indoor coils equippedwith the necessary metering device. Failure to do socould cause a decrease in reliability, capacity andefficiency.

POWERELEMENT

SEAT

PIN

SUPERHEAT SPRING THERMOSTATICBULB

ACCUTRONTM

COMPONENTS

ADAPTER

FLOW CONTROLCHECK VALVE(FCCV) ORIFICE

BODY SEALING CAP

FIELD SUPPLIEDLIQUID LINE

AccutronTM Flow Control Check Valve (FCCV) Typical Thermostatic Expansion Valve

3

Cooling Systems

The diagram below illustrates the proper Manifold Gauge and Temperature Analyzerconnections for charging a split cooling system.

Cooling Package System

1. Attach center hose from manifold to drum ofrefrigerant. Purge center hose with a minimumamount of refrigerant. Use the guidelines fordeminimus release of refrigerant.

2. Purge with a minimum amount of refrigerantand attach suction (compound) gauge hose to thesuction line (larger refrigerant line) pressure tap.This pressure tap may be located on the insideof the cabinet. For example: on the Voyager andImpack lines.

3. Purge with a minimum amount of refrigerant andattach high pressure gauge hose to the liquid line(smaller refrigerant line) pressure tap. This pressuretap is located inside the cabinet.

4. Attach temperature probe securely to the suctionline approximately 6" away from compressor, ifcharging a cooling system with capillary tubes orchecking TXV superheat. Insulate the probe withsuction line insulation to prevent the element frombeing influenced by the surrounding air. Allowadequate time for system temperatures to stabilizebefore recording the temperature.

Split System

1. Attach center hose from manifold to drum ofrefrigerant. Purge center hose with a minimumamount of refrigerant. Use the guidelines fordeminimus release of refrigerant.

2. Purge with a minimum amount of refrigerantand attach suction (compound) gauge hose tothe suction line (larger refrigerant line) pressuretap. This pressure tap is located on the suctionline service valve.

3. Purge with a minimum amount of refrigerantand attach the high pressure gauge hose to theliquid line (smaller refrigerant line) pressure tap.This pressure tap is located on the liquid lineservice valve.

4. Attach temperature probe securely to the suctionline near the service valve (if charging a coolingsystem with capillary tubes or checking TXVsuperheat). Insulate the probe with suction lineinsulation to prevent the element from beinginfluenced by the surrounding air. Allow adequatetime for system temperatures to stabilize beforerecording the temperature.

4

On either style of system, if refrigerant must be removed to

achieve charge balance, an approved refrigerant recovery

system and an approved storage tank must be used.

Heat Pump Systems

The diagram below illustrates the proper Manifold Gauge and Temperature Analyzerconnections for charging a split heat pump system in the cooling or heating mode.

Heat Pump Package System

1. Attach center hose from manifold to drum ofrefrigerant.. Purge center hose with a minimumamount of refrigerant. Use the guidelines fordeminimus release of refrigerant.

2. Purge with a minimum amount of refrigerant andattach suction (compound) gauge hose to low sidecharging port. This charging port (pressure tap) isinside the cabinet of the heat pump and is pipeddirectly to the suction line at the Compressor.

3. Purge with a minimum amount of refrigerant andattach the high pressure gauge hose to the highside charging port. The high side charging port(pressure tap) is inside the cabinet of the heat pumpand is piped directly to the discharge line at thecompressor. Use this tap to obtain head pressurewhen charging heat pumps in the heating orcooling mode.

4. Attach the temperature probe securely to the suc-tion line approximately 6" away from compressor,if charging a system with indoor capillary tubes bythe superheat method or a heat pump with capillarytubes by the hot gas method. Insulate the probewith suction line insulation to prevent the elementfrom being influenced by the surrounding air. Allowadequate time for recording the temperature.

Heat Pump Split System

1. Attach center hose from manifold to drumof refrigerant. Purge with a minimum amountof refrigerant. Use the guidelines for deminimusrelease of refrigerant.

2. Purge with a minimum amount of refrigerant andattach suction (compound) gauge hose to low sidecharging port. This charging port (pressure tap)★on older models protrudes from the corner servicevalve panel of the heat pump and is piped directlyto the suction line at the compressor. On currentmodels this pressure tap is inside the cabinet.

3. Purge with a minimum amount of refrigerant andattach the high pressure gauge hose to the high sidecharging port. The high and low sides charging ports(pressure taps)★ on older models protrude from thecorner service valve panel of the heat pump and arepiped directly to the discharge and suction lines atthe compressor. Use this tap to obtain head pressurewhen charging heat pumps in the heating or coolingmode. DO NOT use the pressure tap on the liquidline (small) service valve for charging or performancemeasurements. On current models, this pressuretap is inside the cabinet.

4. Attach the temperature probe securely to the suctionline near the service valve if charging a system withindoor capillary tubes by the super heat method ora heat pump with capillary tubes by the hot gasmethod. Insulate the probe with suction lineinsulation to prevent the element from beinginfluenced by the surrounding air. Allow adequatetime for recording the temperature.

5

On either style of system, if refrigerant must be removed to

achieve charge balance, an approved refrigerant recovery

system and an approved storage tank must be used.

★★

★★

Equipment Pressure Taps (General)

Pressure taps may be located on the equipmentcabinet, on the refrigerant lines, or on refrigerant lineservice valves. Some equipment may have pressuretaps at more than one location. See the charging chartslocated on the equipment for selecting proper pressuretaps. Inaccurate pressure readings will occur if thewrong taps are used. Pressure taps located on or insidethe equipment cabinet must be used on heat pumps.Inaccurate readings and damage to pressure gaugeswill result if the wrong taps are used.

Three phase 7.5 ton and larger split system modelshave pressure taps located on service valves whichare closed when the valves are fully open in theiroperating position (backseated). After connectinggauges to pressure taps, the service valves areturned one turn in a clockwise direction to open thepressure taps. Do not exceed one turn.

When pressure measurements have been completed,return the valves to their fully backseated position.Replace and tighten valve caps securely to preventleaks. Cover caps on pressure taps should alwaysbe replaced and tightened after making pressuremeasurements to prevent leaks. Do not overtightencaps on Schrader type pressure taps. The tap maybe damaged preventing future use.

Manifold Gauge Removal

Caution must be used when removing hoses from arefrigerant system. When attaching and removingmanifold gauges access valve actuators manufacturedby Robinair, Watsco, J.B. Industries, Imperial Eastmanand Delco may be used to prevent loss of refrigerantcharge. Liquid refrigerant when released can causesevere burns and permanent eye damage. Alwayswear safety glasses, face mask and protective clothingwhen handling refrigerants.

6

Charging Capillary Tube/FCCV – Cooling Mode Only – R-22

Current Superheat Method

1. Measure indoor dry bulbtemperature. (Return air at airhandler).

2. Measure outdoor dry bulb tempera-ture. (Measure at outdoor unit).

3. Measure suction pressure at suctionpressure tap.

4. Measure suction temperature beforethe suction service valve on a splitsystem or 6" away from the compres-sor on a package system.

5. You may determine the actual systemsuperheat in degrees by referring toa temperature pressure chart or thelow side manifold gauge and themeasured suction line temperature.

6. *Find the intersection when theoutdoor temperature and indoortemperature meet and read degreessuperheat. If unit superheat is morethan 5° above chart value, add R-22until within 5°. If unit superheat ismore than 5° below chart value,remove R-22 until within 5°, usingan approved recovery system.

7. If superheat is below the 5° limit line,DO NOT ADD R-22.

7

*If Relative Humidity is above 70% or below 20% use indoor WetBulb Temperature.

6

1

LIMIT LINE

70/58

75/63

80/67

85/71

90/75

95/79

DO NOT ADD CHARGE IFPOINT FALLS BELOW THIS LINE

SU

PE

RH

EA

T °

F

5

10

15

20

25

30

35

40

45

50

55 60 65 70 75 80 85 90

2

95 100 105 110 115

OUTDOOR TEMPERATURE °F

6

INDOOR DRY BULB TEMPERATURE °FINDOOR WET BULB*

LIMIT LINE

70/58

75/63

80/67

85/71

90/75

95/79

DO NOT ADD CHARGE IFPOINT FALLS BELOW THIS LINE

SU

PE

RH

EA

T °

F

5

10

15

20

25

30

35

40

45

50

55 60 65 70 75 80 85 90 95 100 105 110 115

OUTDOOR TEMPERATURE °F

INDOOR DRY BULB TEMPERATURE °F

INDOOR WET BULB*

SPLIT SYSTEM

PACKAGE SYSTEM

From Dwg. No. 21C141108 Rev. 0

From Dwg. No. 21B123511 Rev. 0

6

1

2

6

Charts based on 400 CFM/ton indoor airflow and 50% relative

humidity, use only on systems that cool with an FCCV or

capillary tube.

DRYBULB

WET*BULB

INDOOR TEMPERATURE1. REQUIRED SUPERHEAT3

2.

OUTDOORTEMP. -°F

REQUIREDSUPERHEAT

SUCTIONPRESSURE

SUCTIONLINETEMP. -°F

556065707580859095

100105110115

2927242219171512107

———

50515254555657596062636466697175788184879194

707580859095

586367717579

5 10 15 20 25 30

41424344454647484950515253555759616365676971

© 1995 American Standard Inc. * If humidity is above 70% or below 20% use wet bulb temperature.

AIR CONDITIONINGCHARGING CALCULATOR(COOLING CAPILLARY TUBE andFIXED ORIFICE FLOW CONTROL)

a.

3b.INSTRUCTIONS:

1. Set Indicator at INDOORTEMPERATURE -°F.

2. Read REQUIRED SUPERHEATopposite OUTDOOR TEMP. -°F(dash(-)means 5° required).

3a. Reset Arrow at REQUIREDSUPERHEAT.

3b. Opposite measured SUCTIONPRESSURE is the correctSUCTION LINE TEMPERATUREwhen system is properly charged.

If SUCTION LINE TEMP. -°Fis not within ±5°F ofsuction line reading;

NOTE:

1. Add charge to decrease line temperature requirements.2. Remove charge to increase line temperature.3. After adjusting R-22, repeat Steps 3a and 3b (if required).

Select the unit type (SPLIT or PACKAGE).Remove and reverse the slide if needed.

SPLIT

DRYBULB

WET*BULB


2.

OUTDOORTEMP. -°F

REQUIREDSUPERHEAT

SUCTIONPRESSURE


556065707580859095

100105110115

2927242219171512107

———

50515254555657596062636466697175788184879194

707580859095

586367717579

5 10 15 20 25 30

41424344454647484950515253555759616365676971



a.

3b.INSTRUCTIONS:






NOTE:



SPLIT

DRYBULB

WET*BULB


2.

OUTDOORTEMP. -°F

REQUIREDSUPERHEAT

SUCTIONPRESSURE


556065707580859095

100105110115

2927242219171512107

———

50515254555657596062636466697175788184879194

707580859095

586367717579

5 10 15 20 25 30

36373839404142434445464748505254565860626466



a.

3b.INSTRUCTIONS:






NOTE:



SPLIT

Example Slide Rule Calculation – R-22

Example

If Indoor Temperature (1) is ................ 80°

and Outdoor Temperature is ............... 95°

Required Superheat (2) is ................... 10°

If REQUIRED SUPERHEAT (2)is 10°, Set Arrow on 10° (3a)

If SUCTION PRESSURE is 63psig (3b),

SUCTION TEMPERATUREShould be 46°F

8

Performance – Cooling Mode – R-22

Current Method

Split System with a TWV036A Air Handler

Cooling System with FCCV or Capillary Tubes

Indoor Air Flow 1200 CFM

PERFORMANCE CURVES ARE NOT UNIVERSALIndoor Unit Alternates See Correction Table

CORRECTION TABLE

Corr. Press.Indoor Unit CFM S H

COOLING WITH CAPILLARY

BXA036A200A 1200 –3 –6BXA736M2HPA 1200 –3 –6BXA736D200A 1200 0 0BXF036A200A 1200 –2 –4BXA042A200A 1350 0 0BXF048A200A 1350 3 6BWH736A100A 1200 0 0BWV036A100E 1200 0 0BWV736A100E 1200 0 0BWV042A100C 1350 3 6

COOLING WITH FCCV

TWV036A140A* 1200 0 0

Cooling performance can be checked when theoutdoor temperature is above 75°F.

To check cooling performance, allow pressures tostabilize and measure indoor wet bulb temperature,outdoor temperature and pressures (both headand suction).

Locate outdoor dry bulb and indoor wet bulb temp-erature. Find the intersection of the outdoor dry bulbtemperature and indoor wet bulb temperature. Readhead (or liquid) and suction pressure value in the lefthand column of the chart.

Actual Head Pressure should be±10 PSIG of chart.

Suction Pressure should be±3 PSIG of chart.

Example:

Outdoor Dry Bulb Temperature = 90°FIndoor Wet Bulb Temperature = 67°F

Answer:

Suction Pressure @ 1200 CFM = 75 PSIGHead Pressure @ 1200 CFM = 225 PSIG

40 60 80 100 120

INDOOR ENTERING WET BULB °F

LIQ

UID

PR

ES

SU

RE

(P

SIG

)

100

150

200

250

300

350

400

50

55

60

65

70

75

80

85

90

95

100

40 60 80 100 120

SU

CT

ION

PR

ES

SU

RE

(P

SIG

)

1

2

1

2

OUTDOOR TEMPERATURE (°F)


71°F

71°F

59°F

59°F

*Note: Interconnecting Lines: Gas - 7/8" O.D.:Liquid - 5/16" O.D.

†These graphs are for checking unit performance only.

They are not to be used for system charging. To chargesystems with indoor capillary tube, see superheatgraphs or capillary tube slide rule calculation on pages7 and 8.

9

Charging and Performance – Cooling Mode – R-22

Current Method

Split System with a TXC730P3HPA Coil

Cooling System with Thermal Expansion Valve.

Indoor Airflow 1060 CFM


CORRECTION TABLE


TWH036A140A 1200 0 0TWH736A140A 1200 0 0TWH042A140A 1350 3 6TWH742A140A 1350 2 4TWH048A140A 1350 5 10

COOLING WITH TXV

BXA730P3HPA 1125 –5 –10BXA736P3HPA 1200 –2 –4BXF736P3HPA 1200 0 0BXA742P3HPA 1350 0 0BXF748P3HPA 1350 2 4TXC730P3HPA 1060 0 0TXC730P6HPB* 1060 0 0TXC736P3HPA 1200 3 6

Cooling performance can be checked when theoutdoor temperature is above 75°.

To check cooling performance, allow pressures tostabilize and measure indoor wet bulb temperature,outdoor dry bulb temperature and pressures (bothhead and suction).




Example:


Answer:

Suction Pressure @1060 CFM = 74 PSIGHead Pressure @ 1060 CFM = 210 PSIG

40 60 80 100 120


LIQ

UID

PR

ES

SU

RE

(P

SIG

)

100

150

200

250

300

350

400

50

55

60

65

70

75

80

85

90

95

100

40 60 80 100 120


SU

CT

ION

PR

ES

SU

RE

(P

SIG

)

1

3

2

4

1

34

2


71°F

59°F

71°F

67°F

63°F

59°F

*Note: Interconnecting Lines: Gas - 7/8" O.D.:Liquid - 5/16" O.D.

10

Charging By Subcooling – Cooling Mode – R-22

1. Measure Liquid Line Temperature and Refrigerant Pressure at service valves.2. Determine total refrigerant pipe length and height (lift) if indoor section is above the condenser. Plot the

intersection of the two points on the Curve Selection Chart to determine which curve to use.3. Plot the pressure and temperature on the TXV Charging Curve.4. If the lines cross above the curve, remove refrigerant; if below curve, add refrigerant.5. Whenever charge is removed or added, the system must be operated for a minimum of 20 minutes to

stabilize before additional measurements can be made.6. When system is correctly charged, refer to System Performance Curves to verify charge and

performance.7. Exception – Model 6H0024A100A will have 30° subcooling in cooling. Its system performance charts are

with 30° subcooling.

11

70 80 90 100 110 120 130

LIQ

UID

PR

ES

SU

RE

(P

SIG

)

LIQUID TEMPERATURE (°F)

120

170

220

270

420

320

370

REMOVE REFRIGERANT

ADD REFRIGERANT

0 105 15 25 35 45 5520 30 40 50 60 65 70 75 80 85

RE

FR

IGE

RA

NT

LIN

E L

IFT

(F

EE

T)

TOTAL REFRIGERANT LINE LENGTH (FEET)

0

5

10

15

20

25

30

35

40

45

50

55

60

65

LOWER CURVE

MIDDLE CURVE

UPPER CURVE

TXV REFRIGERANT CHARGING CURVEFor charging outdoor units at above 65°F outdoor

temperature in cooling mode and with indoor TXV.

CHARGING CURVE SELECTION CHART

Performance – Heating Mode – R-22

INDOOR CFM

12001100 1300

HE

AD

PR

ES

SU

RE

(P

SIG

)S

UC

TIO

N P

RE

SS

UR

E (

PS

IG)

-20 -10 0 10 20 30 40 50 60OUTDOOR TEMPERATURE (°F)

-20 -10 0 10 20 30 40 50 60OUTDOOR TEMPERATURE (°F)

INDOOR ENTERINGDRY BULB °F

INDOOR ENTERINGDRY BULB °F

400

80

70

60

807060

350

300

250

200

150

100

400

350

300

250

200

150

100

400

350

300

250

200

150

100

80

0

70

60

50

40

30

20

10

80

0

70

60

50

40

30

20

10

80

0

70

60

50

40

30

20

10

This is a Typical Chart and is NotUniversal for All Heat Pumps.

Heat Pump with Capillary Tubes or FCCV

12

3. To check either HEAD or SUCTION PRESSURE enterthe chart on the bottom scale marked OUTDOORTEMPERATURE.

4. Draw a vertical line up to the INDOOR TEMPERA-TURE and read SUCTION PRESSURE or HEADPRESSURE horizontally to the left in the appropriateairflow column.

5. The HEAD PRESSURE reading on the gaugeshould be equal to, or within 5 PSIG BELOW thechart reading.

6. The SUCTION PRESSURE reading on the gaugeshould be within ±3 PSIG of the chart reading.

These charts are located in the outdoor section alongwith the charging charts. If the unit has a capillarytube outdoors these charts should NOT be used forcharging but only to ensure you are in the ball park onthe charge and that the system is working properly.Once this has been established you should use thecharging chart on the outdoor unit. A typical chart isshown on the next page to fine tune the charge formaximum efficiency.

To use the chart:

1. Read indoor and outdoor temperatures at the airhandler and outdoor unit respectively.

2. Measure head and suction pressures at the outsidepressure tap.

Charging – Heating Mode – R-22

Heat Pump with Capillary Tubes or FCCV

This is a Typical Chart and is Not Universal for All Heat Pumps.

80°F70°F60°F

INDOOR DRY BULBTEMPERATURE °F

0 10 20 30 40 50 60

O.D. TEMPERATURE °F

120

140

160

180

200

220

CO

MP

RE

SS

OR

DIS

CH

AR

GE

GA

S T

EM

PE

RA

TU

RE

°F

13

1. Unit must be in the Heating Mode with stabilizedrunning conditions and coil must be free of ice.

2. Measure suction pressure and discharge pressureand check against pressure curve performance inthe outdoor unit. If pressures are within toleranceproceed with the following steps. If pressures arenot within tolerance see preceding page.

3. Measure outdoor dry bulb temperature at theoutdoor unit.

4. Measure indoor dry bulb temperature at theair handler.

5. Measure Hot Gas temperature near outdoor unit.

6. Using the Charging Chart on the outdoor unit findthe intersection where the outdoor temperature andthe indoor temperature meet. Read hot gas temper-ature for this intersection. If measured hot gastemperature is more than 2° above chart value,add R-22 until within 2 degrees. If measured hotgas temperature is more than 2° below chart value,remove R-22 until within 2°, using an approvedrecovery system.

continued

Charging – Heating Mode – R-22 – continued


Current Method

Split Heat Pump with a TWV030A Air Handler

Heat Pump with TXV Outdoor Unit


CORRECTION TABLE


TXA036A4HPA 1125 -1 -15TXA736A4HPA 1125 -1 -15TXC042A4HPA 1125 -1 -20TXA042A4HPA 1125 -1 -20TXA742A4HPA 1125 -1 -20TWV025A140A 900 1 15TWV725A140A 900 1 15TWV730A140A 1000 0 0TWV036A140A 1125 -1 -15TWV736A140A 1125 -1 -15TWV042A140A 1125 -1 -20TWV742A140A 1125 -1 -20TWH024A140A 900 1 15TWH742A140A 900 1 15TWH030A140A 1000 0 0TWH730A140A 1000 0 0TWH036A140A 1125 -1 -15TWH736A140A 1125 -1 -15TWH042A140A 1125 -1 -20TWH742A140A 1125 -1 -20

Heating performance can be checked when theoutdoor temperature is below 60°F.

To check heating performance, allow pressures tostabilize and measure indoor dry bulb temperature,outdoor temperature and pressures (both headand suction).

Locate outdoor and indoor dry bulb temperature,find the intersection of the outdoor temperature andindoor temperature and read head or suction pressurevalue in the left hand column of the chart.

Actual Head Pressure should be:Equal to or less than 5 PSIG of chart.


0 20 40 60 80

INDOOR ENTERING DRY BULB °F.

HE

AD

PR

ES

SU

RE

(P

SIG

)

100

150

200

250

300

350

400

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80

INDOOR ENTERING DRY BULB °F

SU

CT

ION

PR

ES

SU

RE


80°F

70°F

60°F

80°F

60°F

1

3 2

1

3

2

14

Charging By Weight

When a refrigerant system is opened, as in compres-sor replacement, the service technician may want torecharge the system by weight.

Package Systems

The charge stamped on the unit‘s nameplate is thetotal charge. With an accurate scale the weight methodof charging is a rapid and accurate method of charging.

Split Systems

Charging by weight using unit’s nameplate inform-ation only is not an approved method. Prior to 8/98,the refrigerant charge stamped on the outdoor unitnameplate was the total system charge when installedwith 25 feet of refrigerant lines and with the indoorcoil or air handler that the outdoor unit was rated with.The Department of Energy, test procedures require themanufacturer to test and rate their outdoor unit withtheir highest sales volume indoor coil or air handler.This rated combination is listed in the Air Conditioningand Refrigeration Institute Directory, ARI. In the ARIDirectory this tested combination is noted by a ‡ sign.Unless you have this tested combination installed,which is listed in the ARI Directory only, the chargestamped on the outdoor unit nameplate is of littleuse. Further, this nameplate stamping is not thecharge always shipped in the outdoor unit.

The units are shipped with the minimum operatingcharge. The minimum charge is the charge requiredfor 25 feet of line for units produced prior to 8/98. Forunits produced after this date, the shipped charge isthe total system charge when installed with 15 feetof refrigerant lines and the smallest indoor coil, byinternal volume, that the unit is listed within the ARIDirectory. The smallest indoor coil may not be the‡ tested combination. This minimum operating chargeis shipped in the unit so at start up time no refrigerantrecovery will be necessary.

Indoor coils are shipped with a 10 PSIG nitrogenholding charge.

Evacuation

When the refrigerant lines installation is completedand leak checked they and the indoor coil must bedehydrated. Proper dehydration is achieved whenthese components are evacuated to a minimum of500 microns.

15

Calibrating Pressure Gauges

To check pressure gauges, connect the low pressuregauge to a cylinder of CFC-12 and the high pressuregauge to a cylinder of HCFC-22. Make sure thecylinders have been left standing in a stableenvironment, away from radiant heat sources, forseveral hours. This guarantees that the temperatureinside the cylinder is the same as the temperatureoutside the cylinder. Measure the temperature of theair around the cylinders. Now compare the pressureindicated on the gauges to the Temperature-PressureChart. Use the adjustment screw on the gauges tocalibrate them to this pressure.

EXAMPLE: The air temperature is 75°F. The lowpressure gauge (connected to the cylinder of CFC-12)should be adjusted to indicate 77 PSIG. The highpressure gauge (connected to HCFC-22) shouldindicate 132.25 PSIG – or as close as we can read it.

We don’t need a pressure/temperaturechart to make this check. Most manifoldgauges used for refrigeration and airconditioning have this chart “built into”the scales, right on the gauge. Figure 1 isa copy of the scales on a typical set ofrefrigeration gauges. Notice the insidescales labeled HCFC-22, CFC-12 andCFC-502. The values on these scales arethe saturation temperatures for thepressures indicated.

If the low pressure gauge is connectedto a cylinder of CFC-12, and the airtemperature is 75°F, adjust the needleto indicate a temperature of 75°F on theCFC-12 (middle) scale. The pressurereading is about 77 PSIG.

Finally, after calibrating the high pressuregauge to HCFC-22, calibrate it also toCFC-12. This gives us two referencepoints for more accuracy.

Due to the rough handling these testinstruments go through day after day, itis important to develop a habit of routinemaintenance and calibration. Theseinstruments are our “eyes and ears.”How can we quickly and accuratelyservice equipment if we can’t trust themeasurements we make?

1080

60

50

40

3020

10

0

10

20 30

40

50

60010

2030

40

50 60

70

80

9010

0

110

120

2503020

CFC-12

CFC-502

HCFC-2240

30

2010

010

2030

40

5060

70

8090

100

50

4030

2010

010

2030

40

5060

in Hg p.s.i. Figure 1

P P P P

P P P

P S S P S P

WHAT TO CHECK MODE

POWER SUPPLY

HIGH VOLTAGE WIRING

COMPRESSOR IOL

RUN CAPACITOR

START CAPACITOR

START RELAY

CONTACTOR CONTACTS

LOW VOLTAGE W

IRING

CONTROL TRANSFORMER

THERMOSTAT

CONTACTOR COIL

LOW VOLTAGE FUSE

STUCK COMPRESSOR

INEFFICIENT COMPRESSOR

REF. UNDERCHARGE

REF. OVERCHARGE

EXCESSIVE EVAP. LOAD

NONCONDENSABLES

RES. O.D. AIRFLOW

O.D. AIR RECIRCULATION

TXV STUCK OPENSUPERHEAT

RES. I.D. AIRFLOW

REF. CIR. RESTRICTIONS

SOV LEAKING

SOV COIL DEFECTIVE

CHECK VALVE LEAKING

DEFROST RELAY DEF.

DEFROST TERM DEF.

DEFROST CONTROL DEF.

Refrigerant Circuit

Head Pressure Too High

Head Pressure Too Low

Suction Pressure Too High

Suction Pressure Too Low

Liquid Refrigerant Floodback(TXV)

Liquid Refrigerant Floodback Cap Tube

ID Coil Frosting

Compressor Runs Inadequateor No Cooling/Heating

Electrical

Compressor & OD FanWill Not Start

Compressor Will Not StartBut OD Fan Runs

OD Fan Will Not Start

Compressor Hums But WillNot Start

Compressor Cycles On IOL

ID Blower Will Not Start

Defrost

Unit Will Not Initiate Defrost

Defrost Terminates On Time

Unit Icing Up

CHCH

C

CH

HCHCHC

H

HC

CHCH

C

CH

HCHCH

CHCHCH

C - CoolingH - Heating

P - Primary CausesS - Secondary Causes

P S P S SP S P S

S P S S S PS P S S S S PS P P S S S PS S P

P S P SP S S S

P PP P

P S S S PP S S S P

P S S

S P S S S P S S S SS P S S P S S S

P P S P S P PP P S P S P P

P S P S S S PP S P S S S PP P SP P S

P S S S PP S S S P

P S P S S S P S P P SP S P S S S P S P P S

P P S P S SP P S P S S

S S P SS S P S

Troubleshooting Chart-What To Check

16

17

Background

The traditional refrigerants, which have been used incentral air conditioning systems for the past fifty years,have been declared to be a threat to the environment.This is due to the presence of Chlorine in their chemicalmake-up. As a consequence, the air conditioningindustry has been required to search for a suitablereplacement for the most popular of the currentrefrigerants, Refrigerant 22.

Since there are concerns of efficiency and service use,as well as the environmental issues, the job has notbeen easy. To locate a replacement and qualify it foruse in the products we manufacture has taken years ofwork. The refrigerant chosen at this time is Refrigerant410A. Continuing study will be conducted into otheralternates.

Refrigerant Characteristics

The refrigerants developed in the nineteen twenties,using chlorine, such as Refrigerant 22, were uniformin their chemical make-up. Such refrigerants arecalled compounds. Each molecule of the refrigerantis like every other molecule. There is no way in thefield to separate the elements of a compound onceit has been made. Only the most sophisticatedlaboratory equipment can break the building blocksof the refrigerant apart. They contained Hydrogen,Chlorine, Fluorine, and Carbon. These refrigerantswere called HCFC’s.

The alternative refrigerants are different in thematerials used to make them. They are also differentin the manner in which they are made. Refrigerantslike Refrigerant 410A are mixtures of chemicals. Thismeans its components are not as tightly bonded

Refrigerant 410A

together and may separate when released frompressure. It is said to be near AZEOTROPIC in itsconstruction. This word means that it is a mixture,not a compound. It is manufactured by combiningRefrigerant 32 and Refrigerant 125. Both of theserefrigerants are made of Hydrogen, Fluorine, andCarbon and are referred to as HFC’s.

The most important reason for using an alternaterefrigerant is that it does not contain any Chlorine.

Under Federal law, no release of refrigerant is allowedbeyond the minimum required to do service to theproducts. This “DE MINIMUS” or “least possible”loss must be closely observed during service toavoid being subject to possible fines and worse.Even the alternative refrigerants cannot be releasedto atmosphere. The EPA (Environmental ProtectionAgency) requires they must be collected and handledas the existing refrigerants are handled. The issue hereis not Ozone Depletion but the contribution to GlobalWarming and the waste of a valuable resource.

The alternative refrigerant R-410A is not a “drop-in”replacement for R-22. Since they use different oils,different drier construction materials and differentexpansion devices, they require the greatest cautionin replacement situations. At this time, R410A isintended for use in new equipment.

The service tools that are used for the alternativerefrigerant are not the same as the tools used for thecurrent refrigerants and this will be explained in thismanual. Please read and heed the warnings includedin the material in this manual and the manufactures’literature included with the products containing thisalternative refrigerant.

The alternative refrigerant, R-410A, like R-22 is a safeproduct. The same precautions must be observedwhen using either one. However, the technicianmust be aware of several differences in the handlingof R-410A.

When the cylinders containing Refrigerant 410Aare sitting upright, the valve will release liquidrefrigerant. As you can see in Figure 1, there is adip tube in the tank reaching to near the bottom ofthe cylinder. To charge with vapor, turn the cylinderupside down as shown in Figure 2. For cylindersmade after 2⁄99, turn the cylinder upside down asshown in Figure 1A for liquid and upright for vaporas shown in Figure 2A.

Refrigerant cylinders containing Refrigerant 410Aare ROSE colored for identification.

Refrigerant cylinders should never be storedat 125°F or higher temperatures.

Never charge any refrigerant cylinder to greater than80% of its capacity. This was true for Refrigerant 22and is also true for Refrigerant 410A.

Refrigerant 410A boils at -62.9°F. when released toatmosphere. This is twenty degrees colder thanRefrigerant 22. The danger of frostbite is much

Refrigerant Safety

Figure 1 Figure 2 Figure 1A

Invert cylinder if it has NO DipTube for charging. NO Dip Tubeon cylinders manufactured afterFeb. 1999.

Figure 2A

NO Dip Tube on cylindersmanufactured after Feb. 1999.

18

greater on exposed skin. Wear gloves and protectyour eyes with safety glasses at all times.

This refrigerant, like Refrigerant 22, is low in toxicitybut it can still be harmful to humans as it displacesoxygen. Since it is heavier than air, it will formpuddles in low places. Use adequate ventilationnear equipment that is leaking.

Refrigerant 410A is classified as non-flammable. LikeRefrigerant 22, when mixed with air under pressure itcan ignite. Make sure the system is without pressurebefore using a torch for a repair.

Recovery cylinders used with Refrigerant 410Aare not the same cylinders used for Refrigerant 22.Refrigerant 410A recovery cylinders are constructedand tested to higher pressures, 400 PSIG (Poundsto the Square Inch Gauge).

Since the vapor pressure of Refrigerant 410A is from50% to 70% higher than Refrigerant 22 at the sametemperature, service hoses, manifolds and gaugesare all constructed to withstand higher pressures.See Figure 3 for the gauge faces.

The oils used with the alternative refrigerant arealso different. The oil used with the HCFC refrigerantssuch as 22 was mineral oil based. The oil used

Refrigerant Safety

Application Notes

Replacement of a unit using Refrigerant 22 witha unit using Refrigerant 410A requires that boththe indoor and outdoor units be replaced. If theexisting line sets are the correct size and the oil fromthe replaced unit did not contain any acid, the existingline set may be used. The technician should makeevery effort to eliminate any low spots in the linesforming traps. Blow through the lines with dry

19

nitrogen to reduce the amount of oil remaining inthe lines. Then the lines may be used.

Line set lengths and lift restrictions will be similar tothose found in R22 systems. This table is shown fortraining only, and must be used only for that purpose.For line sizing, use Pub. No. 32-3009 latest edition.

5 Ton 4 Ton 3.5 Ton 3 Ton 2.5 Ton 2 Ton 1.5 Ton 1 Ton

7/8 7/8 3/4 3/4 5/8 5/8 5/8 1/2R22 1 1/8 1 1/8 7/8 7/8 3/4 3/4 3/4 5/8

1 3/8 1 1/8 7/8 7/8

3/4 3/4 5/8 5/8* 5/8* 1/2* 1/2*R410A 7/8* 7/8* 3/4* 3/4* 3/4 3/4 5/8 5/8

1 1/8 1 1/8 7/8 7/8 7/8 7/8 3/4

Liquid Line 3/8 3/8 3/8 3/8 5/16 5/16 1/4 1/4

*Rated tube size

Figure 3

with Refrigerant 410A is a synthetic oil calledPOLYOLESTER, abbreviated POE. This oil requiresspecial handling. Since it is hygroscopic in nature,(it picks up moisture from the air), it must be keptsealed until used. Liquid line driers must be changedwhenever the system is opened for service. A goodvacuum cannot adequately remove the moisturefrom the synthetic oil as it did from a mineral oilbased lubricant.

The only system additive that may be used isAcidAway. This additive has ONLY been approvedfor Refrigerant 22, when used in accordance withthe manufacturers’ instructions. All other additivesare discouraged and are not recommended.

The last caution will seem unusual to the technician.Synthetic oil will attack many materials used in roofing.When service is required on equipment mounted on aroof, the surrounding roof must be protected from oilspray or spills. A plastic covering or tarp must bespread around the work area. This caution must betaken seriously! Wiping up spilled oil will not stop itfrom causing long term damage to roofing materials.

20

Charging systems with refrigerants which areclassified as AZEOTROPIC, such as R-410A, requirespecial technique. The blended refrigerants maytend to separate when charging is done with onlythe vapor. This may lead to FRACTIONATION, whenthe refrigerants in the blend do not boil off at the exactsame temperature. Fortunately, R-410A has a well-matched pair of refrigerants. The difference in boilingpoints is less than a degree. This means that for ourpurposes the refrigerant does not require you tocalculate the temperature difference known as GLIDE.For all our work, the refrigerant will have a singleboiling point for each pressure.

The use of liquid in charging is not new. We havecharged the high side of the system with liquid formany years. Charging the low side with liquid willrequire the use of a special charging metering device.A Chargefaster (CH200) by Watsco or its equivalentmust be used. This device allows the refrigerant tobe taken from the cylinder as liquid but puts it into thesystem as a vapor. Remember the refrigerant cylinderwill dispense liquid when it is upright because of thecylinder dip tube on cylinders manufactured before

Feb. 1999. The cylinder must be inverted if manu-factured after Feb. 1999 to obtain liquid for charging.To dispense vapor directly, the cylinder must be inthe upright position.

The subcooling method of charging will be used inthe cooling cycle when an expansion value (TXV) isinstalled in the system.

In this method of charge adjustment, an accuratereading of the temperature of one of the refrigerantlines is required. The standard service thermometeris not accurate or fast enough to properly react. Anelectronic temperature tester, such as an Annie A-8 orequivalent, should be used. The sensing element mustbe tightly connected to the tubing and insulated fromthe ambient air. The charts for charge adjustment willbe found in the equipment and the service literaturefor the product.

While charging the system, allow sufficient time forthe system to react to the adjustment before addingor removing charge.

System Charging Using R-410A

21

R-410A Temperature and Pressure Chart

-60 1.2-55 3.4-50 5.8-45 8.6-40 11.6-35 14.9-30 18.5-25 22.5-20 26.9-15 31.7-10 36.8-5 42.50 48.61 49.92 51.23 52.54 53.85 55.26 56.67 58.08 59.49 60.9

10 62.311 63.812 65.413 66.914 68.515 70.0

16 71.717 73.318 75.019 76.620 78.321 80.122 81.823 83.624 85.425 87.326 89.127 91.028 92.929 94.930 96.831 98.832 100.833 102.934 105.035 107.136 109.237 111.438 113.639 115.840 118.041 120.342 122.643 125.0

44 127.345 129.746 132.247 134.648 137.149 139.650 142.255 155.560 169.665 184.670 200.675 217.480 235.385 254.190 274.195 295.1100 317.2105 340.5110 365.0115 390.7120 417.7125 445.9130 475.6135 506.5140 539.0145 572.8150 608.1155 645.0

Pub No. 34-3400-01

TEMP R410 TEMP R410 TEMP R410

Figure 4

22

Figure 5

Subcooling Charging Table

REQUIRED LIQUID LINE TEMPERATURE

LIQUID PRESSURE REQUIRED SUBCOOLING TEMPERATURE (°F)

AT SERVICE VALVE (PSIG) 8 10 12 14 16 18

189 58 56 54 52 50 48195 60 58 56 54 52 50202 62 60 58 56 54 52208 64 62 60 58 56 54

215 66 64 62 60 58 56222 68 66 64 62 60 58229 70 68 66 64 62 60236 72 70 68 66 64 62

243 74 72 70 68 66 64251 76 74 72 70 68 66259 78 76 74 72 70 68266 80 78 76 74 72 70

274 82 80 78 76 74 72283 84 82 80 78 76 74291 86 84 82 80 78 76299 88 86 84 82 80 78

308 90 88 86 84 82 80317 92 90 88 86 84 82326 94 92 90 88 86 84335 96 94 92 90 88 86

345 98 96 94 92 90 88354 100 98 96 94 92 90364 102 100 98 96 94 92374 104 102 100 98 96 94

384 106 104 102 100 98 96395 108 106 104 102 100 98406 110 108 106 104 102 100416 112 110 108 106 104 102

427 114 112 110 108 106 104439 116 114 112 110 108 106450 118 116 114 112 110 108462 120 118 116 114 112 110

474 122 120 118 116 114 112486 124 122 120 118 116 114499 126 124 122 120 118 116511 128 126 124 122 120 118

23

In the cooling cycle the Subcooling chart shown inFigure 5 will help you to make the decisions whencharging units equipped with thermostatic expansionvalves (TXV). Since the valve controls the superheat,subcooling must be used to determine the correctcharge level.

It is recommended that charging be done in theliquid phase. When adding liquid refrigerant into thelow side of the system, a charge-metering device isrecommended (WATSCO CH200, or equivalent). Allowample time when adding refrigerant for the system tobalance out, to avoid having to recover refrigerant.

Existing Halide leak detectors do not work with R-410A.Existing acid test kits do not work with R-410A. (Newkits are being developed.) Existing driers do not workwith R-410A. Note that although R-410A does notdeplete the ozone layer, all refrigerants must berecovered.

R-410A systems use POE oil, which is not compatiblewith the oils used in R-22 systems. If existing refrig-erant lines are to be used with an R-410A system(assuming that the line sizes are acceptable), theymust be thoroughly blown out with dry nitrogen toremove the old oil. Blow vertical sections from topto bottom.

POE oils absorb moisture very quickly. Keep containertightly closed, whenever possible, and expose thesystem to the atmosphere as little as possible. POEoils can also damage a roof, if spilled.

410A Refrigerant

Vacuum pumps can not remove all of the moisturefrom POE oils. Change the liquid line drieranytime the system is opened to theatmosphere.

Suction line driers are to be left in the systemfor no more than 72 hours. Use only liquid andsuction line driers approved for R-410A.

Since all current R-410A systems are expansionvalve systems, the refrigerant charge is to be checkedby the subcooling method, See Charts 6 and 7 in thecooling cycle. In heating use the heating dischargepressure curves.

Maximum liquid line pressure drop with R-410Asystems is 50 PSI (10° subcooling). Recommendedsuction line pressure drop (2°F) is 4.8 PSI (Round upto 5.0).

At this time, only matched systems are permit-ted with R-410A. Both indoor and outdoor unitsmust be changed in a unit replacement.

R-410A boils at -62.9° at atmospheric pressure,so beware of frostbite!

Line set lengths and lift restrictions will be similarto those found in R22 systems, as long as the riseis limited to 60 feet and the length is 200 feet or less.Tables on the following pages show the line sizes.

24

ERPD 4292A

DISTR T-1

A150999P05 REV.0

R410A Split Cooling Units Only

1. Measure Liquid Line Temperature andRefrigerant Pressure at service valves.

2. Determine total refrigerant pipe lengthand height (lift) if indoor section is abovethe condenser. Plot the intersection of thetwo points on the Curve Selection Chartto determine which curve to use.

3. Plot the pressure and temperature on theTXV Charging Curve.

4. If the lines cross above the curve removerefrigerant, if below curve add refrigerant.

5. Whenever charge is removed or added, thesystem must be operated for a minimum20 minutes to stabilize before additionalmeasurements can be made.

6. When system is correctly charged referto System Performance Curves to verifycharge and performance.

60

50

40

30

25

20

15

10

0

10 20 25 30 40 60 80


TOTAL REFRIGERNT LINE LENGTH (FEET)

MIDDLE CURVE

LOWER CURVERE

FR

IG

ER

AN

TL

IN

E

LI

FT

(F

EE

T)

UPPER CURVE

TXV REFRIGERANT CHARGING CURVE

200

250

300

350

400

450

500

550

600

70 80 90 100 110 120 130

LIQUID TEMPERATURE (°F.)

LIQ

UID

PR

ES

SU

RE

(P

SIG

.)For charging outdoor units with R410A refrigerant at above 65°F

outdoor temperature in cooling mode and with indoor TXV.

REMOVE REFRIGERANT

ADD REFRIGERANT

Chart 6

25

R410A Split Heat Pump Units Only

1. Measure Liquid Line Temperature andRefrigerant Pressure at service valves.

2. Determine total refrigerant pipe lengthand height (lift) if indoor section is abovethe condenser. Plot the intersection of thetwo points on the Curve Selection Chartto determine which curve to use.

3. Plot the pressure and temperature on theTXV Charging Curve.

4. If the lines cross above the curve removerefrigerant, if below curve add refrigerant.

5. Whenever charge is removed or added, thesystem must be operated for a minimum20 minutes to stabilize before additionalmeasurements can be made.

6. When system is correctly charged referto System Performance Curves to verifycharge and performance.

ERPD 4309B

DISTR T-1

A150999P06 REV.0

60

50

40

30

25

20

15

10

0

10 20 25 30 40 60 80


TOTAL REFRIGERNT LINE LENGTH (FEET)

MIDDLE CURVE

LOWER CURVERE

FR

IG

ER

AN

TL

IN

E

LI

FT

(F

EE

T)

UPPER CURVE

TXV REFRIGERANT CHARGING CURVE

200

250

300

350

400

450

500

550

600

70 80 90 100 110 120 130

LIQUID TEMPERATURE (°F.)

LIQ

UID

PR

ES

SU

RE

(P

SIG

.)For charging outdoor units with R410A refrigerant at above 65°F

outdoor temperature in cooling mode and with indoor TXV.

REMOVE REFRIGERANT

ADD REFRIGERANT

Chart 7

26

R-410A Charging and Performance – Cooling Mode

Current Method

Split System with a RWE040E13 Coil

Cooling System with Thermal Expansion Valve.



PRESSURE CURVE CORRECTION PSIG

Alternate Indoor Units With Thermal Expansion Valve

Cooling Heating

Suction Head Suction Head

Indoor Unit CFM Pressure Pressure Pressure Pressure

RWE040E13* 1160 0 0 0 0

RWE037E13 1060 -7 -2 1 53

*Base Indoor Unit(s) Curves on 21X151830 Rev.0

*Note: Interconnecting Lines:Gas - 3/4" O.D.Liquid - 3/8" O.D.

From Dwg. No. 21X151830 Rev. 0

Cooling performance can be checked when theoutdoor temperature is above 65°.

To check cooling performance, allow pressures tostabilize and measure indoor wet bulb temperature,outdoor dry bulb temperature and pressures (bothhead and suction).




Example:


Answer:

Suction Pressure @1160 CFM = 137 PSIGHead Pressure @ 1160 CFM = 340 PSIG

40 60 80 100 120


LIQ

UID

PR

ES

SU

RE

(P

SIG

)

200

250

300

350

400

450

500

1

3

2

4

71°F

59°F

550

600

50 70 90 110

100

105

110

115

120

125

130

135

140

145

150

40 50 70 90 11060 80 100 120


SU

CT

ION

PR

ES

SU

RE

(P

SIG

)

1

34

2


71°F

67°F

63°F

59°F

155

160

165

170


27

R-410A Charging – Heating Mode


Current Method

Split Heat Pump with a RWE040E13 Air Handler

Heat Pump with TXV Outdoor Unit


Heating performance can be checked when theoutdoor temperature is below 60°F.

To check heating performance, allow pressures tostabilize and measure indoor dry bulb temperature,outdoor temperature and pressures (both headand suction).

Locate outdoor and indoor dry bulb temperature,find the intersection of the outdoor temperature andindoor temperature and read head or suction pressurevalue in the left hand column of the chart.

Actual Head Pressure should be:Equal to or less than 10 PSIG of chart.


PRESSURE CURVE CORRECTION PSIG

Alternate Indoor Units With Thermal Expansion Valve

Cooling Heating

Suction Head Suction Head

Indoor Unit CFM Pressure Pressure Pressure Pressure

RWE040E13* 1160 0 0 0 0

RWE037E13 1060 -7 -2 1 53

*Base Indoor Unit(s) Curves on 21X151830 Rev.0

*Note: Interconnecting Lines:Gas - 3/4" O.D.Liquid - 3/8" O.D.

From Dwg. No. 21X151830 Rev. 0

0 2010 30 50 7040 60 80

INDOOR ENTERING DRY BULB °F.

HE

AD

PR

ES

SU

RE

(P

SIG

)

150

200

250

300

350

400

450

20

30

40

50

60

70

80

90

100

110

120

0 20 40 60 80

INDOOR ENTERING DRY BULB °F

SU

CT

ION

PR

ES

SU

RE


80°F

70°F

60°F

80°F

60°F

50 703010


130

140

28

Notes

29

Notes

Pub. No. 34-4100-06 P.I. (L)

american standard system charging manual

Documents

repeat steps

opposite measured

left hand

temperature

approved storage

suction line

thermal expansion

universalindoor