It is me with problem with the upstairs heat pump again. When the compressor comes on, the fan on the compressor starts. Usually within a few seconds, the fan motor shuts off but the compressor keeps running. Before the fan can completely spin down, the fan motor comes on again. It often keeps repeating this, so it is only blowing out the hot air about half the time the compressor is running. I think this must hurt efficiency. What could be the problem?
Has it always done this? Does it coincide with the outdoor temperature? Also the fan doesn't need to force air through the condenser at certain temperatures say below 50F
The title says AC problem, the body talks about heat pump. Which is it doing when the problem is ocurring, heating or cooling. If it's doing this in cooling mode, I'd say it's almost certainly a bad fan or the wiring going to the fan. Not sure how the fan is used in heating mode.
It is a heat pump in A/C mode. I had a lot of problems with this unit about 2 years ago and they replaced the fan motor twice, the capacitor, and the thermostat. It doesn't act like a loose connection because the on/off times seem consistent.
I would think if it's in the mid 80s and in cooling mode the condenser fan should be running 100% of the time the compressor is on. A circuit diagram that shows how the fan is powered would be the place to start, or you could just follow the wires and/or put a voltmeter on the fan and see if it's the power to the fan or the fan that's the issue.
Great thought. IF the OP could contact the mfgr and get a wiring diagram and post it, we could probably settle things quickly, but right now everyone is shooting in the dark.
It is a Rheem RPKA-031JAZ. I googled and couldn't find the info. I went to the Rheem website and searched there, didn't find it. I emailed Rheem, but they don't seem to have it.
Most heat pumps are setup to cycle the condenser fan motor which will cut on and off during moderate to cold outdoor temperatures. I include a condenser fan cycling control on all standard AC units I install for restaurants because the AC is usually run year round and the pressure in the liquid line from the condenser needs to be kept high enough for the AC to operate properly. Some conventional straight AC condensing units have a two speed condenser fan motor and the control may actually cycle the fan on and off if it's cold enough outdoors. You can spend even more money and get a heat pump that has variable speed compressor and fan motors. :-)
If it's a pressure control, the rapid cycling at that temperature could indicate a low refrigerant charge. Model number and information on operation including diagram may show a pressure switch.
She made it clear a while back that it's cooling mode that she's concerned about. And the very first post indicated that the compressor stays on, while the FAN shuts off. That is most certainly NOT a low refrigerant problem.
Do you know anything about condenser fan cycling controls that operate on what's commonly called head pressure? Look it up, try to understand it then get back to someone like me who has about four decades experience with refrigeration and HVAC equipment. Search "head pressure" and "condenser fan cycling controls". If you have a problem understanding it, I can explain it without calling you names or questioning your parentage or brain power. ^_^
I never questioned your parentage or brain power. I do question your ability to read and follow a thread or provide usefull answers. Within a few posts, the OP stated that what she is talking about occurs during COOLING. Yet you come along posting:
"Most heat pumps are setup to cycle the condenser fan motor which will cut on and off during moderate to cold outdoor temperatures."
She said it's mid 80's outside, so what does that have to do with Jan's question?
" I include a condenser fan cycling control on all standard AC units I install for restaurants because the AC is usually run year round and the pressure in the liquid line from the condenser needs to be kept high enough for the AC to operate properly."
Which has what to do with Jan's question?
" Some conventional straight AC condensing units have a two speed condenser fan motor and the control may actually cycle the fan on and off if it's cold enough outdoors. You can spend even more money and get a heat pump that has variable speed compressor and fan motors. :-) "
Which has what to do with Jan's question?
Since you have 40 years experience, presumably you can pull up a schematic for this heat pump. If you can show us where it has a fan control that relies on cycling the fan based on refrigerant pressure in cooling mode, I'll conceed your point. Until then, I doubt it does.
You still missed it. I read her later answer about the temperature. I know the time lines get messed up sometimes but I don't hold it against you. I did look around a bit for a service manual online but I'm not going to spend $10.00 to prove a point on Usenet. At first, I didn't know the temperature outdoors until the OP answered me. So I was operating on a faulty assumption about ambient temperature. This time of year, the temperatures around the country can vary quite a bit. It may hit 90° around here today but it was in the low 50's last week. When the refrigerant charge is low in a unit of any kind, it's going to behave erratically just like me. ^_^
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