Sometimes my A/C short cycles.

Virgil

Member
Occasionally my ac will run and cool fine. other times when it cuts off it will almost instantly start up again. I have no problem with the way it cools, but it drives me crazy cutting on and off.

This is my first post and I did a search on this topic but couldn't find anything.
Thanks in advance for any help...
 

danemayer

Well-known member
Hi Virgil,

Welcome to the Heartland Owners Forum.

Ours has been doing that for about 9 years now. I think it's pretty common. You might try changing the FAN setting on the thermostat to HIGH or LOW. The compressor may still cycle on and off, but the fan noise won't.

If you do that, keep in mind that when you switch the thermostat to HEAT/FURNACE, the A/C blower will run unless you set the FAN back to AUTO.
 

wdk450

Well-known member
If you are saying that the entire AC system (fan AND Compressor) shuts off and then comes back on suggests thermostat or control board (relay?) problems to me. There should be a 30 second power lockout on the control board to protect the compressor. You can test for this by running the air conditioner, turning it off, then immediately turning it back on. There should be a 30 second delay until it comes back on under these conditions.

This troubleshooting guide i found in the forum library might help:
http://manuals.heartlandowners.org/...for_your_RV_Air_Conditioner_and_Heat_Pump.pdf

If it is just the compressor shutting off, the ice sensor in the evaporator might be detecting icing conditions, or there is an over-temperature cutoff switch element mounted on top of the compressor that might be tripping. I mounted an external fan blowing in on the top of the compressor to avoid this on very hot days.

I am assuming you have a Dometic AC, as most AC's installed in Heartlands are Dometic.
 

Virgil

Member
Thanks for the replies, I'll have to play with it and pay more attention to see if it's the compressor or fan or both..
 

Lou_and_Bette

Well-known member
Virgil, ours does the same thing occasionally. I believe it is a function of the A/C's "brain," used for energy conservation? Usually happens on very hot days when A/C is running for longer period of times. When temp at thermostat nears set point, within a degree or two, the A/C senses the temp is nearing the set point and sifts to a lower speed. IIRC, we had a tech lecture at the national rally one year and this was explained by the factory guy. I'm certainly no expert on the A/C system, or the electronics but, after living in our unit full time for the last 7 years, I have some experience with the operation. I believe there is two temp sensors, one at the thermostat and the other in the unit itself. I notice that in the morning when the outside temps are rising, the thermostat in the BR which is mounted on the front wall so gets warmer faster than ambient room air temp and triggers the A/C to come on. The unit engages and begins circulating the air, which in actuality is cooler than wall temp, the unit senses the compressor is not needed to cool the air so it runs for short time and shuts down. After a short time, the unit repeats this cycle until the air temp is above the set temp and then the compressor kicks in. This usually occurs in the early morning, rarely in the evening. Once past this early morning temp discrepancy, the unit functions correctly through out the day. This is all based on speculation gained from hours of listening to our unit operating. So, in short, IMHO, your system is operating as designed. To combat this, when your system starts the short cycling, you can bump T-stat up or down, and it should stop doing this for a while. Good luck
 

Manzan

Well-known member
I had a similar problem. Drove me nuts until I realized that the A/C was blowing on my thermostat. Folded a thin piece of cardboard and placed it over the thermostat. Now it cycles as it should. Jut have to remember to fashion a new deflector each cooling season.
 

D_BTravelers

Active Member
I had the same issue with one of my A/C units in a previous trailer. It would stop and then start again occasionally, then be fine at other times. It finally dawned on me to pull the thermostat off the wall and there I found a wire that was not captured when the connection was crimped. It was touching enough to sometimes work and then not. I removed the old connector and reconnected. Never happened again. No $$ to fix and easy to do.
 
Occasionally my ac will run and cool fine. other times when it cuts off it will almost instantly start up again. I have no problem with the way it cools, but it drives me crazy cutting on and off.

This is my first post and I did a search on this topic but couldn't find anything.
Thanks in advance for any help...

Ours does that so I called Dometic. Seems that is normal for these units.
 
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