New Pool- Heat Pump Questions

[dastro]

We have a brand new 20x40 25K gallon vinyl pool with a Raypak 119K BTU heat pump, Pentair Intelliflo pump (running on average about 1750 rpm), and a Coverstar safety cover. I have a few questions/concerns. On a 80 degree day, it takes about 5-6 hours to gain 2 degrees (pool covered, from 86 to 88 degrees). Is this a normal time period or is it too long? I just took the intake and outflow temps of the heat pump and they are 60 degrees and 54 degrees. I believe the difference is supposed to be 9-12, correct? Also, the heat pump sounds fairly loud with a decibel reading of 73 at about 3 feet. There is also a steady, throb-like sound coming from the compressor that rises and falls quickly, I'm not sure if that is normal or not.

Any advice would be appreciated!

 

[JamesW]

119,000 btu per hour should add about 0.57 degrees Fahrenheit per hour to the water. 5 hours = 2.85 degrees. 6 hours = 3.42 degrees.

Then, you have losses, which depend on many factors.

Heat rise at 40 gpm should be about 5.94 degrees Fahrenheit between water entering and leaving the heater.

Heat rise depends on flow rate. At 20 gpm, the heat rise will be double and at 80 gpm, it will be half.

How are you getting the 54 and 60 degree temperatures. That doesn't match the 86 to 88 you say earlier.

For the sound, we would need a video. Maybe post on YouTube and link.

 

[dastro]

119,000 btu per hour should add about 0.57 degrees Fahrenheit per hour to the water. 5 hours = 2.85 degrees. 6 hours = 3.42 degrees.

Then, you have losses, which depend on many factors.

Heat rise at 40 gpm should be about 5.94 degrees Fahrenheit between water entering and leaving the heater.

How are you getting the 54 and 60 degree temperatures. That doesn't match the 86 to 88 you say earlier.

Thanks. The 86 to 88 was on another, warmer day. The 54 and 69 was today.

- - - Updated - - -

Typo, meant to say 54 and 60.

 

[JamesW]

A 6 degree rise is about right assuming about 40 gpm flow.

The heat loss is difficult to determine. A cover is the biggest difference.

Based on the expected gain and estimated loss, everything seems about right.

Maybe post a video of the heater operating so we can hear it.

 

[dastro]

I may have caused some confusion. The 54 degrees is the intake AIR temp and 60 degrees is exiting AIR temp of the heat pump. This is only 6 degrees and I believe difference for a normally operating heat pump is 10-12 degrees.

 

[JamesW]

The air coming out should be cooler than the air going in because heat is being removed from the air to go into the water.