Heat Pump Temperature Not Rising

ChristopherDB

Gold Supporter
In The Industry
Apr 21, 2021
79
Florida
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Aquapure 1400
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?
 
Last edited:

wireform

Silver Supporter
In The Industry
Aug 15, 2017
3,105
Spring Valley, NY
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

TFP Expert
Mar 2, 2011
28,200
Is this the same one that is making a lot of condensation?


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

TFP Expert
Mar 2, 2011
28,200
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

Gold Supporter
In The Industry
Apr 21, 2021
79
Florida
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Aquapure 1400
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.
 
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