DeltaT..pool heater make..

[oilman52]

MaxTemp....MaxPool 36. Started it up today with covers off and coils started to freeze up. Took gas line pressure ,40 psi.

[simpleman]

I'm lost Oilman.. what type of pool heater?

I can only assume it a poolheater that uses a vaporsystem
to generate its heat.

If thats the case,then at 40 psi saturated temps I'm sure the coil would start to freeze.R22
The only other reason the coil would freeze on the water side would be not enough flow thru the system,other then that the water must be real cold or she low on freon.

[oilman52]

It is a heat pump style simpleman. Pool temp. was 62.

[oilman52]

There was plenty of water flow going thru the hoses.

[DeltaT]

Originally posted by oilman52
It is a heat pump style simpleman. Pool temp. was 62.

First problem is the pool water temp. 62 is way too cold for this or most any pool heat pump system to work. 62 is what your ambient temp is comparative to a normal refrigeration system. 62 degrees is hitting the condensor hot gas straight out of the compressor.

So, first, believe it or not, you got to get the pool water up above 75 or so or the system will continue to ice on the outside coils. Or you could cheat and throttle down the pool water by-pass to keep the head pressure up...but you have to stay with the system and watch it.

Depending on the ambient temp where the pool is, and I assume it's outdoors and uncovered, raising the pool water temp to around 80 degrees or so will take a couple of days.

Do you have a backup gas fired or electric boiler? If so turn it on to raise the pool water first. Once the water gets up to 75 or so then do the following:

Check the temp rise from the inlet to the outlet of the pool heater. You must use very good contact sensors and allow the system to run for 15 minuts plus before reading the temperatures. It should be around a 4 to 6 degree rise. If not regulate the pool water by-pass valve until you reach that value.

If that temp rise cannot be achieved then we need to step into some different areas before you start doing things to the refrigeration circuit.

There are some assumptions that need to be made. One is that the outside air temp is above 65 or so degrees, the pool filter is clean, no air in the filter tank or anywhere else and that the pump is pumping well. The newer plastic impeller pumps will loose GPM very slowly and it's hard to catch. And the pool water pressure system should be below 20 pounds.

You should also have built into the pool heater a pressure switch or a flow switch, (pressure switch is better) that will shut off the compressor if the pool water pump stops pumping water. Easy to check. Run the system with pump on and shut off the pump. The heat pump should shut down almost immediately.

And you should also have a high temp limit on the discharge of the pool heat pump to help protect the heat exhanger against overheating. Should be around 100 to 110 degrees.

The heat exchanger can actually boil water if the compressor is allowed to run with no flow.

So get the pool water temp up first and we'll take it from there. Yes, most pool heat pumps are built to maintain the pool water temp but not heat it up! There are a few that will but the odds are you don't have one.

[oilman52]

No back up heater. Pool is outdoors. Hopefully the outdoor temp. will pick up soon.

[DeltaT]

Originally posted by oilman52
No back up heater. Pool is outdoors. Hopefully the outdoor temp. will pick up soon.

You can attempt to regulate the pool water by-pass valve to keep the head up and the suction up and still allow some heat into the pool to get the temp up. You will have to watch the system though because as the pool water increases more GPM is required through the heat exchanger.

Regulating the bypass will also give you some chance to see if the refrigeration circuit is charged properly and/or the compressor is pumping correctly but this is not the correct way to check. Getting the pool water up is the key.

I hope the pool is covered as it will heat up much quicker.