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oltma026 12-08-2009 12:33 PM

Heat Pump quitting
When I turn my heat pump on to heat it will work for a few hours and turn on and off as the temp fluxuates, basically it works fine. I can adjust the heat below the actual temp and it will shut off like it should, and then bring it back above the actual temp and it will kick on again.

However, after a few hours it will stop working and the temperature drops. When it stops it is still making a noise, but not the same as when its working properly and the fan on the unit stops spinning.

The only way to restore it is to shut it off completely and wait a couple hours then turn it back on and the cycle repeats.

I guess my question is, could this be a thermostat wiring problem, thermostat setup problem, or something wrong with the actual unit?


Marty S. 12-08-2009 05:12 PM

Could just be going into defrost. Compressor still runs when the fan is off?

hennyh 12-08-2009 05:44 PM


Originally Posted by Marty S. (Post 363610)
Could just be going into defrost. Compressor still runs when the fan is off?

Marty is probably right on.

What's the outdoor temp and humidity when this happens? How long does this last?

Defrost is usually needed when temp is <40 and humidity is high. The defrost cycle only lasts several minutes. If that's the case don't turn off the unit. It needs to clear frost from the coils and the defrost cycle does just that.

beenthere 12-08-2009 06:02 PM

Yep. Sonds like its going into defrost.

Next time it happens. Don't touch anything. Just leave it run. If its in defrost. It will start heating again in less then 15 minutes(often less then 5 minutes, varies with how heavy of a frost).

It should be bringing on aux heat during defrost. You could have a bad strip heater.

oltma026 12-09-2009 03:46 PM

It seems like once it goes into defrost mode it never comes back, I let it run all night once and it wouldn't start heating again until it was switched off and then back on again a couple hours later.

Could the compressor just not be able to clear the frost out of the system but still be able to heat for a period of time?

Also the Aux heat isn't working properly either. It never comes on, even when I switch the thermostat to Emer. Heat option.

Another thing I noticed this afternoon was that when it reached the temperature it was set to reach it kept blowing, but not warm air, so I just shut it off, and within an hour the outside temp had raised the temp 2 degrees. Should a heat pump keep a room from rising above the set Temp?


beenthere 12-09-2009 04:43 PM

Sounds like you have both mechanical and electrical control problems.

Doubt anything wrong with the compressor(or did you mean condenser).

Need someone to check the control wiring, contactors, defrost board, strip heaters, thermal links, sequencers, thermostat, low voltage, line voltage wiring, condition of both coils, and the refrigerant charge.

That list isn't as bad as it first sounds.

You may be able to do some of it yourself.

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