Heat Pumps and Electric Heating - Heat pump turns on then fan stops

I am baffled over my heat pump. It started a week ago when I heard a loud humming noise. Went to the outside unit and saw that the outside fan was not running. I flipped the breaker to save from further damage. I read about it possibly being the capacitor so I pulled my dual capacitor and ran a test...if it was done correctly it was still good as the meter came back to the left. After having power off to the unit for a day I put the cap back in flip the breaker and the fan turns on. I was happy for a while then a few hours later I walk out to check on things and see that the fan isn't running and the outside screen is cold and is slushy like. I flip it off wait a few hours...turn it on and the fan runs again only to cut off about an hour later. What the heck is goin on????? Please help.

hey sorry to add this thread but i have the same problem. My capacitor was replaced because my fan stopped working. Now my fan turns on and about an hour later shuts off, with the compressor still running.

I've noticed that if i set the temp to below 71, my heat pump works fine, anything higher than that the fan shuts off after an hour of working fine. What could be the problem?

You both realize that heat pumps shut off their fan during their defrost cycle? Some units have temp sensors to tell the unit when it needs defrosting. Others just use a timer set to defrost every 30/60/90 minutes of operation depending on the setting. Defrost time is usually about 5 minutes after which the unit will go back into heating mode and the fan will restart.
-doug.

You both realize that heat pumps shut off their fan during their defrost cycle?

Yes, my first thought as well. By resetting the breaker you are resetting the timers and controller from continuing with defrost.

What are the outdoor temps when this is happening? And are you getting heat from your registers when this is happening due to the aux heat tempering the defrost cooling?

Outdoor temps have been about 40-50s. As stated the unit will usually kick on with outside fan running for about half an hour then the fan will stop if I walk out an hour later or so I notice that the screen on the outside unit is very cold and has a feel of ice but sounds like the outside unit is still running. In fear of the unit going bad I threw the breaker. I have been able to go back after a few hours and turn the breaker back on and the fan will kick back on the outside unit. I put a shop vac to the outside line to clean it. I've heard I could need a charge of freon. I used to think it was the cap but after time being able to restart it and a test that showed cap was good I am set that it isn't that. Still baffled. Any ideas on what to try?????

Lets go back to the basics: how do we know this is just not defrost. 40 is a point where defrost should be done.

So what is your aux heat and is it coming on during these episodes? How did it cool over the summer?

When I turn the heat on, the AUX heat light is on at my thermostat. I have tried the Emerg Heat but it doesn't feel like I am getting any real good heat from that either. As far as cooling in the summer...The cooling was fine until a week or so ago when I began having issues with the fan running. The AC was turned on I heard a loud humming walked out and the outside unit was warm and the outside fan was not running. Since then there has been the issue with either cool or heat of the fan kicking on if it sits, will run for a bit, then the outside fan stops. The heat seems to be on when it is first turned on, which the outside fan runs, but after a period of time it feels like just cool air blowing.

If you are in AC mode and the fan was not turning its not a defrost issue and is some sort of fan problem. Have you tried giving the fan a push with a stick? If this starts it normally I would say it was a bad start cap, but since you have already checked that I suppose it could also point to a bad winding on the fan motor. If the stick trick doesn't yield any results your looking at no power at the fan and that could be anything from a loose connection to a bad fan relay. My only suggestion would be to get the DMM back out and work your way back from the fan.

And low freon would not stop the fan.

At first I began to think of the fan too. Up to the point that when I turn the unit on...it runs for a bit then the fan stops and with the heat on it has been freezing up. When I let it sit for a bit I can turn it back on and it kicks back on again to start the same cycle. With the fan running I was beginning to believe that the unit needs to be charged