caleffi. natural solutions. · caleffi. natural solutions. 47 years of growth. ... delta t controls...

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CALEFFI. NATURAL SOLUTIONS.47 years of growth.

WebsiteTechnical Trainer

Caleffi North America Inc.Caleffi North America Inc.414414--238238--23602360www.caleffi.uswww.caleffi.us

e-mail:: [email protected]: www.caleffi.us

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Solar Controllers


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Webinar Outline• OVERVIEW• CONTROLLER MODELS• SYSTEM ARRANGEMENT OVERVIEW• SYSTEM ARRANGEMENT DETAILED ANALYSIS• Basic Delta T control (Arrangement #1)

Solar system with heat exchanger (Arrangement #2)Heat Dump (arrangement #2, iSolar3 or Arrangement #3, iSolar PLUS)Solar system with tank heating in layers (Arrangement #4)Solar system with valve logic (Arrangement #5)Solar system with pump logic (Arrangement #6)Solar system with 2 collectors, 1 tank (East-West) (Arrangement #7)Solar System with backup heating from a wood boiler (Arrgmt #8)Solar System with heating circuit reverse raising (Arrangement #9)

• MOST COMMON REASONS FOR TECH CALLS• Q & A

e-mail: [email protected]: www.caleffi.com

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OVERVIEW OF CALEFFI SOLAR CONTROLLERS

e-mail: [email protected]: www.caleffi.com

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Solar Controllers

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Different Schematics accomplished with “Arrangements”

Sample Displays

System Arrangement #1

Simple Delta T Control (S1 compared to S2)

S3 is display only

S4 can be used for energy metering or display only

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Delta T controls solar pump (S1 compared to S2)

2nd Delta T (S3 compared to S4) and tank temp (S4) controls 2nd pump with modulation


Delta T controls solar pump (S1 compared to S2)p p ( p )

S3 works as a thermostat only. Set points (AHO and AHF) can be flipped to add or extract heat.

Can be used to drive indirect pump from boiler or TT contacts through a relay

Time clock function can lock out boiler backup during peak solar hours

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Staged Delta T control to load upper portion of tank first

Heat monitoring possible with S4


Heat Diversion arrangement

Control looks at delta T and set point of priority tank firstControl looks at delta T and set point of priority tank first, then to delta T and set point of 2nd tank

Typically used with DHW as priority and swimming pools or heating systems as secondary.

Valve should be located after heat exchangers on return line. Can also be used for heat dumping.

S4 can be used for heat monitoring

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Same as arrangement #5 except with pumps


East – West Collector arrangement

MUST use pumps, cannot be done with a pump and valve

Can provide solar in situations that don’t have any southern exposure

Produces about 20% less energy than the same amount of collectors facing south

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Arrangement for boiler back up using a wood fired boiler

Programmable temperature of solid fuel boiler TFSB before R2 fires


Arrangement for space heating only


Delta T between S3 and S4 controls diverting valve. If the solar tank is warmer than the system return water, the valve diverts water to the tank so it is pre-heated before going to the boiler.

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Arrangements per Controller

User Interface

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Display

Relay #2 is on

A relay has been forced on or off (hand mode)

Warning

Freeze protection active or min collector temp (CMN) not reached

Collector cooling

Temp Sensor

Relay #1 is on

g

Warning

gor re-cooling active

Appears for programmable variables. Flashes when changing variable value

Pumps, flashes when running

valueNote:

The sensor being displayed will blink slowly (1 per sec)

A fast blinking sensor indicates an error with that sensor (Triangle will flash and LED will blink red)

Installation

solar pumppower supply (pre‐wired)grounds

FuseOptional Sensor (display only)

solar panelsensor

(p )

tank bottomsensor

Return fluid temp sensor for BTU monitoring

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Optional Enclosure

Temperature Probe

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Variable Speed Pumping Principle of Operation

If using a variable speed pump, when DTO (12o Fdefault) is reached the pump will run at full 100% speedfor 10 seconds. After 10 seconds the pump will modulatefor 10 seconds. After 10 seconds the pump will modulatedown to the minimum pump speed (nMN- 40% default).It runs at this minimum pump speed when the ∆T is ≤DTS (20o F default). When ∆T reaches DTS the pumpwill increase speed by 10% until it increases ∆T by RISdegrees (4o F default) and continues in RIS degreeincrements correlating to additional 10% pump speedincrements. When the ∆T decreases, the pump voltagewill drop by 10% increments versus RIS degreeincrements until the ∆T drops below DTF (8o F default).p ( )This principle of operation applies to any iSolarController from Caleffi when used for the primary solarpump or for other system pumps in other arrangements.

Variable Speed Pumping Example Values

DTS=20; RIS=4∆T Pump %20 40%

DTS=10; RIS=2∆T Pump %

≤ 20 40%24 50%28 60%32 70%36 80%40 90%

≤ 10 40%12 50%14 60%16 70%18 80%20 90%

44 100% 22 100%

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Arrangement #1

Most basic installation, simple ∆T control

Required sensors: S1 (Collector) and S2 (Tank)Optional sensors: S3 (for display purposes only) and S4 (return to collector, can be used to measure energy generated)

O t t R1 (S l b d l t d f i bl dOutputs: R1 (Solar pump- can be modulated for variable speed or set to discrete output)

• Controller senses collector and tank temperatures (COL & TST).• If collector temp is 12oF (default) higher than tank temp (DTO) the

pump runs.• Pump stops running if collector temp comes within 8oF (default) of

tank temp (DTF). • If it’s a variable speed model, the pump will run at full speed for 10

seconds. After 10 seconds the pump will modulate down to 40%. If the ∆T is increasing, the pump will increase speed by 10% until it settles out at a flow rate. If the ∆T decreases, the pump voltage will drop by 10% until the ∆T stabilizes.

Arrangement #1 User InterfaceCOL = Collector TempTST = Temp of Storage TankS3 = Sensor #3 temp (display only)S4 = Sensor #4 temp (display only, also shown as TRF if heat

monitoring is enabled)n% = pump speed (displayed as a percentage)

Display Only

n% = pump speed (displayed as a percentage)hP = Operating hours of solar pumpKWH = Kilowatt hours collected (if heat monitoring is enabled)MWH = Megawatt hours collected (if heat monitoring is enabled)TIME = Military clock (can be programmed by hitting “set”)

(TIME available only in PLUS models.)

Hit and hold “+” button for 3 seconds to enter program mode

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Arrangement #1 Programming Settings

Arrangement #1, single tank application

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Arrangement #1, two tank application

Arrangement #1, pre-heat indirect application

In this example an aquastat would need to fire the indirect

Boiler can be traditional or modcon

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2nd Delta T (S3 compared to S4) and tank temp (S4) controls 2nd pump with modulation

Note: Works like Arrangement #8 except adding heat to a secondary tank instead of bringing in heat to the solar tank.

Heat monitoring not available with S4.

Arrangement #2

Solar System with heat transfer to second tank. Can allow solar pre-heat to reduce boiler usage for second tank.

Required sensors: S1 (Collector), S2 (Lower Tank), S3 (Upper Tank), S4 (Tank 2)

Optional sensors: none availableOutputs: R1 (Solar pump- can be modulated for variable speed or set to discrete output), R2 (pump for heat exchange)

• Controller senses collector and tank temperatures (COL & TST1).• If collector temp is 12oF (default) higher than tank temp (DTO) the

pump runs.• Pump stops running if collector temp comes within 8oF (default) of tank

temp (DTF). • If it’s a variable speed model, see principle of operation.• This arrangement is used to transfer heat from the solar storage tank to

Like Arr #1 g g

a secondary tank. Tank 1 temp (MN3F) AND Tank 2 temp (MX3F) must be met before R2 will fire. R2 will turn off if tank 1 drops below MN3O AND tank 2 exceeds MX3O. Besides meeting the requirements of MN3F, MN3O, MX3F and MX3O, the DT30 must also be met to fire R2, and of course, similarly DT3F to stop R2.

• Three conditions must be met for R2 to activate: 1. Tank 1 (S3-TSTU) is warm enough AND 2. Tank 2 (S4-TST2) is cold enough AND 3. DT3O for pump to run. (Tank 2 can not be hotter than Tank 1 to extract heat)

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Arrangement #2 User InterfaceCOL = Collector TempTST1 = Temp of Storage Tank Lower Sensor (S2)TSTU = Temp of Storage Tank Upper Sensor (S3)TST2 = Temp of Tank 2 for Heat Exchange Sensor (S4)n1% = Solar Pump (1) pump speed (displayed as a percentage)

2% H t E h P (2) d (%)

Display Only

n2% = Heat Exchange Pump (2) pump speed (%)hP1 = Operating hours of solar pumphp2 = Operating hours of heat exchange pumpTIME = Military clock (can be programmed by hitting “set”)




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Arrangement #2 Programming Settings (continued)

NOTE:MN3O and MN3F defaultsdefaults are too low for normal usage.Adjust MN3O first, then MN3F.3

Arrangement #3 (arr #2 for iSolar3 and 4)

∆T control and thermostatic control

Required sensors: S1 (Collector), S2 (Tank #1) and S3 (Tank#2)Optional sensors: S4 (return to collector, can be used to measure energy generated)

Outputs: R1 = Solar pump, can be modulated for variable speed or set to discrete outputR2 = Can fire a diverting valve for heat dump, a pump for indirect DHW, or a signal to a boiler (via a relay) for DHW.

• Controller senses collector and tank temperatures (COL & TST).• If collector temp is 12oF (default) higher than tank temp (DTO) the

pump runs.• Pump stops running if collector temp comes within 8oF (default) of tank

temp (DTF). • If it’s a variable speed model the pump will run at full speed for 10If it s a variable speed model, the pump will run at full speed for 10

seconds. After 10 seconds the pump will modulate down to 40%. If the ∆T is increasing, the pump will increase speed by 10% until it settles out at a flow rate. If the ∆T decreases, the pump voltage will drop by 10% until the ∆T stabilizes.

• S3 controls Relay #2 via AHO (after heating “on”) and AHF (after heating “off”. Setting AHO below AHF will add heat to the tank. Setting AHO above AHF will extract heat from the tank.

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Arrangement #3 User InterfaceCol = Collector TempTSTL = Temp of Storage Tank Lower Sensor (S2)TSTU = Temp of Storage Tank Upper Sensor (S3)S4 = Sensor #4 temp (display only, also shown as TRF if heat


Display Only

hP1 = Operating hours of solar pumphP2 = Operating hours of 2nd pump or valveKWH = Kilowatt hours collected (if heat monitoring is enabled)MWH = Megawatt hours collected (if heat monitoring is enabled)TIME = Military clock (can be programmed by hitting “set”)




Continued…….

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Arrangement #3 Programming Settings (contiuned)

SMX = 140 (sensor #2)AHO = 180 (sensor #3)AHF = 160 (sensor #3)OCX = ON (CMX = 250 or less)When S2 reaches set point the solar pump turns off, if the collectors reach the CMX set point, collector cooling will start. If the top of the tank reaches 180, the 3-way valve will transfer Any future collector cooling will be diverted to

Arrangement #3 for heat dumping

will transfer. Any future collector cooling will be diverted to the heat dissipater. Once the tank cools down to 160, the 3 way valve will transfer back.

Z-one valve AFTER heat exchanger

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Arrangement #3(Using iSolar to fire boiler for indirect, provides timing function)

Relay required for dry contacts to boiler

S1

S3

S2

Arrangement #3, R2 firing indirect pump

SMX = 140 (sensor #2)AHO = min indirect tank temp ~ 110 F (sensor #3)AHF = max indirect tank temp ~ 125 F (sensor #3)R2 wired to indirect pumpWhen S3 reaches 110 F R2 will start the indirect pump, the flow switch could then be used to close TT contacts on the boiler. Once S3 reaches 125 F, R2 will turn off the indirect pump

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Staged Delta T control to load upper portion of tank first

Typically used for systems with very large storage tanks

Heat monitoring possible with S4

Arrangement #4

Solar System with tank heat in layers (2 coil tank charging), typically for use with very large storage tanks

Required sensors: S1 (Collector), S2 (Lower Tank), S3 (Upper Tank)

Optional sensor: S4 (return to collector, can be used to measure t d)energy generated)

Outputs: R1 = Solar pump, can be modulated for variable speed or set to discrete outputR2 = Fires a diverting valve for charging upper tank layer

• Controller looks at delta T (S1 vs S2) and set point of priority layer (coil) first, then to delta T (S1 vs S3) and set point of secondary coil.

• Like Arr #1: Basic delta T control and, if it’s a variable speed model, see principle of operation. The pump speed controls operate, per the priority settingsetting.

• When the lower sensor (S2) set point (S1MX) is satisfied the solar pump (R1) continues running. The controller looks at the collector temperature (S1) and tank upper sensor temperature (S3). If the collector temp is higher than 12 degrees F (programmable) R2 fires diverting solar fluid to charge the upper coil for tRUN (programmable) pumping time. It then checks S2 (Priority 1-but also adjustable making S3 Priority 1 if desired) for conditions required to charge. If the lower coil continues to be satisfied, upper coil charging resumes for tRUN time.

• Controller knows, in this arrangement, that R2 is on/off, not modulating.

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Arrangement #4 User InterfaceCol = Collector TempTSTL = Temp of Storage Tank Lower Sensor (S2)TSTU = Temp of Storage Tank Upper Sensor (S3)S4 = Sensor #4 temp (display only, also shown as TRF if heat


Display Only

hP = Operating hours of solar pumpKWH = Kilowatt hours collected (if heat monitoring is enabled)MWH = Megawatt hours collected (if heat monitoring is enabled)TIME = Military clock (can be programmed by hitting “set”)




Continued…….

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Control looks at delta T and set point of priority tank firstControl looks at delta T and set point of priority tank first, then to delta T and set point of 2nd tank

Typically used with DHW (tank 1) as priority and swimming pools or heating systems as secondary.

Valve should be located after heat exchangers on return line. Can also be used for heat dumping.

S4 can be used for heat monitoring

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Arrangement #5

Solar system with valve logic (similar to #4)

Required sensors: S1 (Collector), S2 (Tank 1), S3 (Tank 2)Optional sensor: S4 (return to collector, can be used to measure energy generated)

Outputs: R1 = Solar pump, can be modulated for variable speed or set to discrete outputR2 = Fires a diverting valve for charging tank 2

• Controller looks at delta T and set point of priority tank first, then to delta T and set point of 2nd tank.

• Like Arr #1: Basic delta T control and, if variable speed pump, pump speed controls operate, per the priority setting.

• When the priority sensor (S2) set point (S1MX) is satisfied the solar pump (R1) continues running. The controller looks at the collector temperature (S1) and 2nd priority sensor temperature (S3). If the collector temp is higher than 12 degrees F (programmable) R2 fires diverting solar fluid to charge the 2nd tank for tRUN (programmable) pumping time. It then checks S2 (Priority 1-also adjustable making S3 Priority 1 if desired) for conditions required to charge. If the priority sensor continues to be satisfied, 2nd tank charging resumes for tRUN time Priority 0 means when both delta Ts call for heat, they are taken in numberical order..

• To charge tank designated Priority 1, R1 is fired only.• To charge tank designated Priority 2, R1 and R2 are fired.• Collector cooling, if enabled, by default goes into Priority tank without

firing R1.• Controller knows, in this arrangement, that R2 is on/off, not modulating.

Arrangement #5 User InterfaceCol = Collector TempTST1 = Temp of Storage Tank 1 Sensor (S2)TST2 = Temp of Storage Tank 2 Sensor (S3)S4 = Sensor #4 temp (display only, also shown as TRF if heat


Display Only

hP = Operating hours of solar pumpKWH = Kilowatt hours collected (if heat monitoring is enabled)MWH = Megawatt hours collected (if heat monitoring is enabled)TIME = Military clock (can be programmed by hitting “set”)



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Continued…….


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Arrangement #5, solar system with valve logic



Same as arrangement #5 except with pumps

Heat monitoring is not available using S4

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Arrangement #6

Solar system with pump logic (similar to #5 but with pumps)

Required sensors: S1 (Collector), S2 (Tank 1), S3 (Tank 2)Optional sensor: S4 (display only)Outputs: R1 = Solar pump 1, can be modulated for variable speed

or set to discrete outputR2 = Solar pump 2, can be modulated for variable speed or set to discrete output

• Controller looks at delta T and set point of priority tank first, then to delta T and set point of 2nd tank.

• Like Arr #1: Basic delta T control and, if variable speed pump, pump speed controls operate, per the priority setting.

• When the priority sensor (S2) set point (S1MX) is satisfied the pump (R1) stops. The controller looks at the collector temperature (S1) and 2nd priority sensor temperature (S3). If the collector temp is higher than 12 degrees F (programmable) pump R2 fires to charge the 2nd tank for tRUN (programmable) pumping time. It then checks S2 (Priority 1-also adjustable making S3 Priority 1 if desired) for conditions required to charge. If the priority sensor continues to be satisfied, 2nd tank charging resumes for tRUN time. Priority 0 means when both delta Ts call for heat, they are taken in numberical order.

• To charge tank designated Priority 1, R1 is fired only.• To charge tank designated Priority 2, R2 is fired only.• Collector cooling, if enabled, by default goes into Priority tank w/o firing

R1.

Arrangement #6 User InterfaceCol = Collector TempTST1 = Temp of Storage Tank 1 Sensor (S2)TST2 = Temp of Storage Tank 2 Sensor (S3)S4 = Sensor #4 temp (display only)n1% = Solar Pump (1) pump speed (displayed as a percentage)n2% = Solar Pump (2) pump speed (%)

Display Only

n2% Solar Pump (2) pump speed (%)hP1 = Operating hours of solar pump (1)hp2 = Operating hours of solar pump (2)TIME = Military clock (can be programmed by hitting “set”)



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Continued…….


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East – West Collector arrangement

MUST use pumps, cannot be done with a pump and valve

Can provide solar in situations that don’t have any southern exposure

Produces about 20% less energy than the same amount of collectors facing south


Arrangement #7

Solar system with 2 collectors, 1 tank (East-West)

Required sensors: S1 (Collector 1), S2 (Lower Tank), S3 (Collector 2)

Optional sensor: S4 (display only)Outputs: R1 = Solar pump 1, can be modulated for variable speed

or set to discrete outputR2 = Solar pump 2, can be modulated for variable speed or set to discrete output

• Simultaneously, controller looks at collector 1 and collector 2 temperatures and tank temperature.

• If collector 1 temp is higher than 12 degrees F (programmable) the pump 1 will run and basic delta T control and, if variable speed pump, pump speed controls operate for collector 1speed controls operate for collector 1.

• For the east-west application, as the sun moves away from the east facing collector, delta T falls, stopping pump 1, and when collector 2 temp is higher than 12 degrees F (programmable) the pump 2 will run.

• Similarly, for collector 2 basic delta T control and, if variable speed pump, pump speed controls operate for collector 2.

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Arrangement #7 User InterfaceCol 1= Collector 1 Temp Sensor (S1)TST = Temp of Storage Tank Sensor (S2)Col 2= Collector 2 Temp Sensor (S3)S4 = Sensor #4 temp (display only)n1% = Solar Pump (1) pump speed (displayed as a percentage)n2% = Solar Pump (2) pump speed (%)

Display Only

n2% Solar Pump (2) pump speed (%)hP1 = Operating hours of solar pump (1)hp2 = Operating hours of solar pump (2)TIME = Military clock (can be programmed by hitting “set”)




Continued…….

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Arrangement for boiler back up using a wood fired boiler

Programmable temperature of solid fuel boiler TFSB before R2 fires

Works like Arrangement #2 except adding heat to solar tank instead of extracting it


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Arrangement #8

Solar System with backup heating from a wood boiler

Required sensors: S1 (Collector), S2 (Lower Tank), S3 (Upper Tank), S4 (Tank for solid fuel boiler)

Outputs: R1 = Solar pump, can be modulated for variable speed or set to discrete outputR2 = Pump for solid fuel boiler, can be modulated for variable speed or set to discrete output

• For the solar pump, delta T for S1 and S2 work just like arrangement #1.• Has minimum setting for water coming from wood boiler (MX3O and

MX3F) to protect the wood boiler.• The two delta Ts are independent.• Not really a 'backup' but consider it like another 'free' source.• Tank 1 upper sensor (S3-TSTU) temperature (MN3F) AND Solid Fuel

Boiler sensor (S4-TSTL) temperature (MX3F) must be met before R2 willBoiler sensor (S4 TSTL) temperature (MX3F) must be met before R2 will fire. R2 will turn off if tank 1 drops below MN3O AND the Solid Fuel Boiler exceeds MX3O. Besides meeting the requirements of MN3F, MN3O, MX3F and MX3O, the DT3O must also be met to fire R2, and of course, similarly DT3F to stop R2.

• Three conditions must be met for R2 to activate: 1. Tank 1 (S3-TSTU) is cold enough AND 2. Boiler (S4-TFSB) is warm enough AND 3. DT3O for pump to run. (Tank 2 can not be hotter than Tank 1 to extract heat)

Arrangement #8 User InterfaceCol = Collector Temp Sensor (S1)TSTL = Temp of Storage Tank Lower Sensor (S2)TSTU = Temp of Storage Tank Upper Sensor (S3)TSFB = Temp of Solid Fuel Boiler Tank (S4)n1% = Solar Pump (1) pump speed (displayed as a percentage)n2% = Pump for solid fuel boiler (2) pump speed (%)

Display Only

n2% Pump for solid fuel boiler (2) pump speed (%)hP1 = Operating hours of solar pump (1)hp2 = Operating hours of solar pump (2)TIME = Military clock (can be programmed by hitting “set”)



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Continued…….


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Arrangement for space heating only


Delta T between S3 and S4 controls diverting valve. If the solar tank is warmer than the system return water, the valve diverts water to the tank so it is pre-heated before going to the boiler.

Arrangement #9

Solar System with heating circuit reverse raising

Required sensors: S1 (Collector), S2 (Lower Tank), S3 (Upper Tank), S4 (Heating circuit return)

Outputs: R1 = Solar pump 1, can be modulated for variable speed or set to discrete outputR2 = Fires a diverting valve to pre-heat water before

going into boiler

• Like Arr #1: Basic solar system delta T control and, if variable speed pump, pump speed controls operate, for collector/lower tank/solar pump, to heat solar storage tank.

• Controller looks at upper tank (S3) temperature and heating circuit return (S4) temperature. If the tank temp is higher than 12 degrees F (programmable) R2 fires diverting solar fluid to the tank to be pre heated(programmable) R2 fires diverting solar fluid to the tank to be pre-heated before going to the boiler. If the tank temp comes within 8 degrees F (programmable) relay 2 is deactivated sending water directly to the boiler for heating.

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Arrangement #9 User InterfaceCol = Collector Temp Sensor (S1)TSTL = Temp of Storage Tank Lower Sensor (S2)TSTU = Temp of Storage Tank Upper Sensor (S3)TRET = Temp of Return Circuit (S4)n% = Solar Pump (1) pump speed (displayed as a percentage)hP = Operating hours of solar pump

Display Only

hP = Operating hours of solar pumpTIME = Military clock (can be programmed by hitting “set”)




Continued…….

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Some Common Technical Calls

Q: Can you activate the backup heating element in a storage tank with the 2nd relay?

A: Yes, but the iSolar controllers only have a 1 amp maximum output so an external relay must be used. This would allow you to take advantage of the internal clock in the iSolar plus (arrangement #3). Keep in mind, the Caleffiinternal clock in the iSolar plus (arrangement #3). Keep in mind, the Caleffi tank has a built in aqua-stat.

Q: Does the iSolar3 provide a way to fire a boiler in afterheat mode through TT dry contacts?

A: Yes. However, the iSolar controllers output 120 VAC so an external relay would need to be used as the dry contact. Another method is to have the iSolar controller fire the indirect pump and then use a flow switch to fire the TT contacts (slide 34 schematic)

Q: If we change settings in an arrangement, and the power goes out, will it maintain the changes or revert to factory settings? For how long will it keep settings if the power is disconnected?

A: The changes will remain for the lifetime of the controller. However, if the arrangement is changed or if the units are changed (degrees F or degrees C) the control will go back to factory settings for all variables.

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Q: Is heat dumping necessary or is it for warranty purposes?A: This depends on system design, location, and how it is used and the load.

For instance, heat dumping may be needed when adding more collectors to an existing system. Or, to protect the system during extended absences such as vacations.such as vacations.

Q: What is a heat dissipater?A: Could be as simple as a fin tube in the basement or outside. Could be a

swimming pool.


Q: How does one determine the minimum pump speed?A: The minimum pump speed should be no lower than 40% and the factory

default is now 40%. If you find you have an older controller that has 30% as the default it is strongly advised to manually adjust that to 40%. At 30% pump speed the pump motor may stop and it may take a significant increasepump speed the pump motor may stop and it may take a significant increase of more than the 10% increments programmed into the control for it to begin to operate. The reason for pump speed control is to minimize electrical consumption by the pump and to improve heat transfer efficiency by reducing the flow to the collectors on cloudy days to improve solar thermal transfer and reduce electrical consumption. Besides the default value, what other factors should be used to adjust the minimum to another value? One reason is that there may be another value for minimum speed for other brands of solar pumps to be aware for the same reasons. Also, in installations with solarflex runs greater than the standard 50 feet coil length, 40% may be too low to keep the check valves fully open. In this case you may elect to increase the minimum value to 50 or 60% to create sufficient pump head to keep the check valves open and deliver the required flow.

Q: Can you tell me what the blue electrical component is in the spare part bags? I have a customer asking what it is and how it should be replaced. I thought it was a varistor but I’m not positive, nor do I know how it would get replaced.

A: This is a capacitor 4.7 nF and it is only for semi conducted relays. It is there to be connected if there is an actor with a low load like valve connected.

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Q: I made simulator box to observe the iSolar PLUS controller. How come when the relay is off I am still recording voltage at the output?

A: The iSolar controllers with variable speed output use triacs instead of mechanical relays. Triacs require a small load on the output otherwise the voltage will drift upward. If the simulator box were to be connected to avoltage will drift upward. If the simulator box were to be connected to a pump you would not record any voltage at the output. A small resistor could be used to bring the voltage down.

Q: For arrangement #5, how do you disable pool heat functionally during winter operation?

A: One way is to change the set point for sensor S3 (S2MX) so it would never reach it during the winter cold. Another way would be to force the Relay R2 to off (HND2). The drawback here is that you would get a persistent flashing red light and warning symbol. Or, you could simulate S3 with a toggle switch with a fixed resistance, taking the sensor out of the loop.

Q: Isn’t arrangement #8 more similar to #3 than #2? A: No, #3 works strictly off a temperature for R2, it doesn’t look at delta T.

Q: Can #8 be used for oil or gas fired boilers?A: No, use arrangement #3 with the thermostatic functions for on/off switching.

The wood boiler needs a certain minimum temperature to operate properly.


Q: In the arrangements indicating heat monitoring is available via sensor S4, is a flow meter required for heat quantity measurement? If not, how does it calculate it? When do you use a flowmeter for this?

A: No, an external connected flowmeter is not required. In those arrangements where heat monitoring is available with S4, enable the OHQM function. It’s awhere heat monitoring is available with S4, enable the OHQM function. It s a low-cost option as this feature is built-in to the controller at no extra cost. You have to input a fixed value for your estimated maximum system flow in liters per minute (we weren’t able to get that converted yet) for the FMAX value as well as the anti-freeze type for MEDT and the glycol percentage MED%. Note, the maximum flow rate (FMAX) is limited to 20 lpm. The controller then calculates the heat quantity as S1 and S4 vary versus the fixed flow rate and the anti-freeze type and percentage. This isn’t exact, but a close estimation for those interested in reading what they are harvesting. There is a flowmeter available from Caleffi, the WMZ meter. You can use that when you want to be more accurate, or the arrangement you’re using doesn’t allow for ‘onboard’ heat monitoring, or if your flow rate is greater than 20 lpm(5.3 gpm).

Q: Why does the pump run at no more than 50 or 60% speed (nNM% reading on the display)?

A: Refer to the variable speed pumping principle in this training presentation. Check the settings for DTS and RIS. The factory defaults of 20 and 4 respectively may be causing this, limiting the % speed due to the operating characteristics of the system. You might consider reducing both values to allow the pump speed to increase faster during the operating cycle. Consider, too, that if your system is harvesting energy, it may be doing it efficiently this way, using less electricity to power the pump. “Don’t fix it if it isn’t broken” may be in order here.

10/8/2009

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CALEFFI North America Inc.

3883 West Milwaukee Road Milwaukee, WI 53208Tel. +1 414-238-2360

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