AC Compressor cycling

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
D

DoraTheExplorer

New member
Joined
Jun 18, 2017
Posts
2
I just bought this 2005 24ft Thor class C. We took it out on its maiden voyage this weekend. I noticed that the while the ac is on the compressor is cycling on and off. While lying awake at night I actually noticed it had a consistent pattern of about 70 seconds on then 70 seconds off. It would keep doing this until the temperature was reached then shut off like normal. When it restarts because of temperature the same thing happens. I am not sure if this is normal or not. The fact that it is consistent seems that it might be normal, but in my experience in auto ac tells me it is not normal. If it is on Auto the fan does stay on during this cycling so that seems to eliminate a thermostat issue.
 
IF this happens mostly at night, it might be due to it freezing up due to high humidity. I have heard of this happening on basement units and was either due to low freon or freeze sensors having a problem. Since the fan continues to run it will defrost after which the compressor starts up again. It just continues on with this cycle until teperatures increase and humidity drops or until you shut it down.
 
Sounds right. Pressure builds up on high side then compressor turns off. Pressure goes down then compressor turns on again. All controlled by what is called a trinary switch.
 
The cycling is normal in the sense that the a/c is doing it per design, to protect itself from damage and still keep cooling. However, it is dealing with an exceptional internal condition and is NOT the expected mode of operation. The a/c has sensors for high internal pressures and for a freeze-up condition and it cycles the compressor to allow conditions to moderate some.  Difficult to say whether you encountered just the right combination of temperature and humidity to trigger that reaction, or if there is a problem in the a/c causing excessive pressure build-up or internal freeze-up. Both are possibilities.

I would say to give it another chance on the next trip. If the problem recurs, further investigation is needed. If not, it was a chance thing.
 
So based on my experience with working on cars and some houses, if the evaporator is actually frozen up from humidity then air flow is greatly restricted and you can tell that pretty easily. Anyone know if this holds true for RV ac.
 
You must log in or register to reply here.

Latest posts

Members online

Total: 526 (members: 6, guests: 520)

Forum statistics

Threads
131,964
Posts
1,388,308
Members
137,717
Latest member
aquaticvegetation
Back
Top Bottom