Heat pump

Apr 6, 2008
Looking to add a heat pump to my in ground pool. I currently run my pump between 12-14 hours per day. My question being, when the heat pump is set up to produce a certain temp and I turn off my pump and filter system will I then need to reset the heat pump with proper settings etc. or will it just remain where it was before turned off??? Does the heat pump turn off and on by itself according to water flow??? Not sure exactly how they operate and any info would be helpful. I know how they transfer heat and such just not quite sure how to run one. Thanx.


Well-known member
Apr 22, 2008
Central Texas
Though I don't have a heater, my controller is capable of controlling one. It has a separate circuit that turns the heater off 20 minutes or so before the pump turns off. I guess that this lets the heat exchanger cool down fully before stopping the water flow.

I've always assumed that the heater would come back on at the same temp setting as when it went off, but since I don't have a heater I can't say for certain. I'm sure that someone with a heater will chime in with the right answer for you. :)


New member
Apr 29, 2008
I have a Jandy heat pump and there is a low flow indicator that shuts the heat pump off if the pressure decreases to a specific point. I tend to run my pump 24hrs a day in the summer when the heat pump is running. I thought of installing a timer but my heat pump is hardwired in and I didn't really want to fool around with the electricity with the fear that I would fry my heater. This summer I thought I would just run my pump 12hours a day and let the low flow indicator shut off my heater. Is this a bad idea?


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
All the heaters I know of remember the temperature setting across power cycles.

Any heater will turn off if there isn't enough water flowing through the heater. However, that sensor can be finicky and fail sometimes, so many people like to have the added safety of an electrical connection that turns off or disables the heater when the pumps isn't running. Depending on the heater you may need to wire it to turn off power to the heater or the heater might have a control connection that it can use to sense of the pump is powered. An automation system normally takes care of turning the heater off at the right time and it is also possible to get a timer with a fireman circuit that will turn the heater off early. Some heaters need the extra time to cool down and others are fine with getting powered down right when the pump is powered down.


TFP Expert
Apr 16, 2007
Ft Lauderdale, Florida
Heat Pumps are different from gas heaters and do not require a cool down mode (firemans switch protection).
Heat Pumps require a quick disconnect from the main circuit breaker and are not required to be interfaced with the circulation pump's operation.

There is an internal pressure switch that tells the heat pump when there is sufficient flow for operation. When the pump turns off, the heat pump will cycle down too, because of the pressure switch.

Any failures of the pressure switch will allow the heat pump to turn on, but the temperature sensors on the water side, and freon side will further protect the heat pump from operation and component damage.
Basically, when it sees the freon temperatures fluctuating different from it's design, it will shut down the compressor and flash a code indicating such.

Bear in mind too that some heat pumps have the capability of activating the pump after it is off (time clock override), for the sake of maintaining the water temperature to your desired setting.
The heat pump can also allow the pump to continue to run, after the normal time clock mode (time clock extend) if the desired temperature setting has not been met by the end of the time clock cycle.

There are internal memories that are retained if you desire to connect the heat pump to be interfaced with the pump so that it turns off at the same time.