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Troubleshooting Guide for Heat Siphon Heat Pumps

Heat Siphon Technical Support: 800-447-9667

If you have reason to believe your pool heater is not performing correctly, follow the appropriate steps below BEFORE CALLING YOUR DEALER:


Heat Siphon won't start

Your Heat Siphon is installed and wired but will not start. This could be a new installation or a unit that has been working fine for years

Check your breaker to make sure it isn't tripped and power is going to the unit

Make sure thermostat is turned up higher than the water temp

Your pump must be on

Heat Siphon will not shut off

After running ok for a period of time and turning on when heat is required and off when the set point is reached, you now have an overheated pool or spa and the unit just keeps running. Almost always this is due to one of two problems

Contactor is welded shut after experiencing excessive chatter, a lightening strike or prolonged low voltage power

Thermostat bulb or water temperature sensor is out of the heat exchanger well and is sensing the outside air temperature instead

Heat Siphon runs but not heating

After bringing the temperature up to some point it seems to go no further even though your Heat Siphon is running and running. New installations may be a sizing or a runtime problem or you may have low refrigerant pressure which means a leak which must be found and fixed. Most common causes:

Time clock is not allowing enough pump runtime

Pool cover hours not being adhered to if required by HSA sizing

Weather too cold for size selected or Air below 45°F shutting unit off at night

Heat Siphon has noise while running

Running noises are usually an alert to a bigger problem IF they are a NEW noise.

Heat Siphon has noise when stopped

Noises coming from the Heat Siphon when it is off are usually rare but a few normal ones are

a slight buzzing from the 24 volt transformer which should be almost imperceptable. If it is loud then it may indicate a problem.

a hissing sound immediately after the unit shuts off which is the sound of refrigerant pressures equalizing through the thermoexpansion valve.

bubbles from the pump which indicates a suction line leak in your pool piping


3.0 Owner Troubleshooting

The purpose of this section of the manual is to provide some GUIDANCE FOR HEAT SIPHON OWNERS with little or no technical background who have a problem with their Heat Siphon. If our guidance here doesn't solve the problem CALL YOUR INSTALLER and refer him to the Installer Section of this manual. He will contact the factory service center for additional service if required.

When you apply power to your Heat Siphon through the disconnect and circuit breaker, usually one of three things will happen



(C) IT STARTS & RUNS but doesn't heat

3.1 Unit Does Nothing

1. Is power on?

2. Thermostat set too low? ( turn fully clockwise-unit should come on)

3. Pool pump on and valves properly set?

4. Water flow confirmed from pool through heater and back to pool?

5. Air too cold? -Air temperature below approx. 42°F will shut unit off automatically to prevent icing. (Wait for air temperature to reach 45°F to 48°F - unit should automatically reset and turn itself on)

6. Time delay activated by brief power interruption? (Wait 5 minutes - unit should restart)

42°F Heat Siphon Shuts Down Below 42°F to Prevent Evaporator Icing and Automatically Restarts at 48°F SvcMan98owner 9 10/24/00, 2:26 PM O - 10 HEAT SIPHON Owner

7. Is breaker tripped? You may have a bad breaker or faulty wiring, loose wires or poor

connection in the junction box . Have your installer check the wiring and breaker.

NOTE: Some brands of GFI type breakers are extremely sensitive and are susceptible to false tripping. Have your installer check all wiring between the unit and the breaker and make sure the breaker is wired right .

8. Call your dealer. - His first step should be to check & adjust the water flow switch

3.2 Unit Tries to Start then Does Nothing

1. Time delay activated by brief power on/off? (Wait 5 minutes-unit should restart)

NOTE. The combination of a cold pool (below about 50°F) and a low air temperature (below about 45°F) MAY causetemporary on off cycling of the Heat Siphon. A pool cover and /or 50°F air temperature will eliminate this cycling and allow normal heating operation to resume.

2. Is the air below 45°F to 48°F and the pool water cold? (Wait for air temperature and/

or pool to reach 50°F - unit should restart automatically and resume normal heating)

3. Is the pool filter clean and pool water flow stable? A clogged filter or air leak in the pool pump return line can cause erratic water flow and air in the lines which in turn can cause Heat Siphon to cycle- restore the correct water flow.

4. Is the fan running when the unit is running? - (if not call dealer)

3.3 Unit Runs But Doesn't Heat


1. Air leaving colder? If not call dealer

NOTE: If Heat Siphon's air outlet is noticeably (5 to 10°F) cooler than the inlet air, then the unit is providing heat to pool . The unit may not have been running long enough to heat the pool (see next step), or the unit may be undersized. (See proper sizing section above)

2. Pool pump running long enough each day? Normally 12-14 hours/day is sufficient if

Heat Siphon is sized properly (let pool pump run continuously for 24 hours to SvcMan98owner 10 10/24/00, 2:26 PM O - 11 HEAT SIPHON Owner find time required-if not heating call dealer)

3. Is there abnormally high heat loss? No cover on extremely windy day? (Cover pool and run pool pump 24 hours. If still not heating call dealer)