Advice Needed: Heat Pump Compressor Intermittently Shuts on and Off
Hi, I'm new to this site. Can't get any straight answers from my contractor, so I thought I would give this a try. Appreciate if anyone can provide some advice what is going on with my heat pump.
Situation: I have a 3-ton ground-source heat pump which I use for heating and cooling. The unit is about 2 years old. The unit is in my basement, when I run it continually the compressor will shut off every 3 hours or so for about 30 minutes or so, then it will restart on its own. Then it runs fine for another 3 hours or so, then shut off again for another 30 mins. This has been going on since I bought the unit. I am trying to figure out if this is normal. I thought that compressors could run continuously.
More info: the unit has water circulating from a well to do the heat exchange with the freon. The thermostat turns on an actuator on the unit which allows water to circulate, the actuator in turn sends a signal to turn on the compressor. During the 30 mins while the compressor shuts off, the well water continues to circulate. So the thermostat and actuator seem fine. Hope this is clear, I am not an expert on this.
My contractor advises that compressor shutting down is normal, that it needs to "cool down". Somehow does not sound right. Does anyone know if this is normal or what the problem may be?
Thanks in advance!
When you run it continually? I don't know what that means. Sounds like you have the fan set to run continous, in which case the fan will continously blow air. The compressor cannot be set for continous operation unless its running at below the thermal balance point. The t-stat cycles the compressor on and off to maintain the t-stat setpoint. However, if you meant that the compressor was cycling off while the t-stat was still calling for heat, then that would mean that there some sort of fault taking place locking out the compressor until the fault clears itself.
sounds like the thermal overload keeps tripping.
I don't know about GS heatpumps, but normal systems don't have this behavior unless something is wrong. Compressors should be able to run constantly all day if needed because they are internally cooled by the cool refrigerant that it sucks in to compress.
Ask your contractor to show you some documentation that your compressor needs to cut out for 30 minutes after a three hour run time. If it is part of the normal running process, then it should be written in the installer's guide or the users manual; both books the installer should have left with you.
Is a closed loop? Is the well sized correctly?
Whats your make and model number ?
Thanks for your comments. To answer your questions:
When I say "run continually", I mean that I set the thermostat on a high setting so that the set temperature is never reached (I shut off the breaker for the 10KW auxiliary electric heater). Does the same thing in summer time in cooling mode. For all practical purposes in winter I would like to keep the 10KW auxiliary off except for the coldest nights.
As for the "loop", this is an open loop not a closed loop. I have two wells, with a submersible well pump in one well that feeds the unit, then the water is returned to the second well. As for the well, I have plenty of ground water, and the well works great, circulates 49F ground water through the unit at 7 GPM (I won't get into details on the plumbing). This is well within the range recommended by the install manual.
I read the installer manual and there is no mention of the compressor needing to shut off periodically.
The Make and Model are Geonergy model GA36, runs on R-22. This is made by "Airtechni", they are based in Montreal, Canada (I live in Quebec).
Also, I've learned how to check for error codes in the unit, and there are no codes in memory.
I can't read French so there website was no help. Do they have a English site?
Unfortenately no English on their website, it was never any good anyways. If there is any info that you would need from the installation manual, I could look for this and scan it. Now that they phased the R-22 models, no more info on these.
My system is nothing fancy, pretty much a basic heat pump connected to a forced air duct system.
A wireing schematic could tell the story and no your compressor should not be turning off every 3 hours unless told so.
Originally Posted by martin123
Originally Posted by VTP99
The "every" 3 hours is what I'm keying on. Sounds more timed than intermittent.
IF it is "supposed" to, have installer show you on wiring diagram and explain when and why.
I believe your system is the same as the American marketed Geocomfort system and if it is I believe it has copelands 2 stage compressor with comfort alert. Copelands comfort alert can be set to automatically reset faults and in this case could be causing an alert/fault on long run cycles. I dont know for sure how long this takes on the control to fault. This alone would not damage your system since it could run continuously without problems but if there is something causing the long run time like low refrigerant charge ect. there may be a problem.
Thanks for the replies so far. Geocomfort sounds about right, when I go on the Airtechni web site, this is the brand they sell. My model is a few years old, they probably rebranded it.
I don't think that I have a scroll compressor. Also, this is a single stage compressor, not dual stage.
I've attached the installation manual. Page 11 has the wiring schmematic if that is of any help. My model is the GA36 (3 ton).
Also as for the unit shutting off every 3 hours or so, this is a best-guess by being around the house and noticing when the heating or cooling shuts off. I have not physically sat in my basement for 12+ hours. But every 3 hours is a pretty good estimate. The shutting off for 30 mins is more precise because I've measured it while being incidentally in my basement when the compressor shut off. I do recall occasions where have been occasions where it has been less, only perhaps 5-10 mins. If I were to take an educated guess, when it has not been running for too long, shuts off for less time, when runs continually for more than 6 hours, then shuts off more consistently every 3 hours for about 30 mins.
I will try to be more precise. I will get a web-cam today and and record what the unit is doing to see if there is an exact pattern and get back to this forum.
Thanks for all your replies, so far you have been a great help!
Sounds to me like the compressor is shutting down on overload and comes back on when it cools back down, I think you have a flow issue with your water source
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