Heat Pump Temperature Not Rising

[ChristopherDB]

Just installed an Aquacal SQ166R heat pump and it's been running 9 hours and not a single degree increase in temperature. I turned it on at 3pm when outside temperature was 75 and sunny. Water temperature was 78. It's now midnight and it's still 78. Temperature over the past 9 hours slowly dropped to 60. Location is south Florida.

The pool is 18x36 with average depth of 4ft. 16,000 gallons. There is an 18x8 sunshelf included in the pool dimensions. I do not have a cover, only a liquid solar blanket that was poured in yesterday.

Pump is pushing 50GPM through the heater. 126k rated BTU but at 80 degree water temperature, 50 degree air temperature, and 63 percent relative humidity it's rated at 82k BTU which is close to today's conditions. Return jets are blowing 5 degrees warmer than suction temperature.

Is this performance expected?

 

[wireform]

No a hp expert and someone will chime in soon enough. Your solar liquid blanket is useless if the water is moving and needs to be reapplied when pumps and all are off.

 

[JamesW]

Is the air coming from the fan cold?

Measure the amperage.

Is the compressor on?

 

[JamesW]

Is this the same one that is making a lot of condensation?

Aquacal Condensation Drain port

I just installed an Aquacal heater and it's producing so much water that it's flooding the equipment pad. The manual says it can produce up to 10 gallons per hour. Aquacal sells a condensation drain line kit which appears to just be a 1/4 tube connected to a barb that threads into what looks...

www.troublefreepool.com

If the water is not from a leak, the condensation indicates that the compressor is working and heat is moving from the air to the water.

Check the capacitor if the compressor is not running.

You can hear the compressor running and the amperage should be close to nominal.

 

[JamesW]

Pump is pushing 50GPM through the heater. 126k rated BTU but at 80 degree water temperature, 50 degree air temperature, and 63 percent relative humidity it's rated at 82k BTU which is close to today's conditions. Return jets are blowing 5 degrees warmer than suction temperature.

50 gpm is 3,000 gallons of water per hour or 25,000 lbs of water per hour.

82kbtu into 25,000 lbs of water is 3.28 degrees rise from enter to exit of the heater.

If you are getting a 5 degree rise, then the heat pump is probably working correctly.

A 5 degree rise corresponds to 125,000 btu/hr of heat input.

16,000 gallons is 133,440 lbs of water.

82,000 btu into 133,440 lbs. is 0.615 degrees per hour gain, which can easily be lost from evaporation.

 

[ChristopherDB]

Thanks James! Those numbers do add up. I spoke to Aquacal for an hour today. They want to send somebody out next week to check the unit. Their sizing calculator is severely off. The representative used the calculator today and estimated 10 degree heat loss per day and that I would need to run 10 hours a day to maintain temperature. What the calculator doesn't appear to consider is the efficiency drop of the heat pump at temperature below 80, meaning is is much less than 1 degree increase per hour as they claim. Also they said it only considers running the heat pump during daytime hours. If that's the case, I'd have a 10 degree drop at night, then during the day I would need to run the heat pump for 10 hours to get to 85 degrees. That means my pool wouldn't get up to temperature until 6pm every day, leaving a few hours of usable swim time. Their claims just don't add up. I was even told this unit is oversized for the pool which apparently is not the case.



With the 5 degree temperature delta, I think it's operating correctly and I'm just fighting against the air temperature and wind without a cover.

 

[wireform]

This time of the year you can benefit alot from a solar cover. There will be much less heat loss and will have solar gain during the day with minimal evaporation.

 

[ps0303]

I get people calling me all the time with heat pump problems when the weather gets cool in Florida. Heat pumps can't keep up with the cool weather. Gas is the only efficient way to heat any body of water when it is cold out here in Florida. So yes, you are fighting a losing battle with running the heat pump now.