A/C Confusion - Or is it just me???

I know there has been a lot of different questions regarding the A/C units... I had some trouble with mine last season, the comperssor wouldn't shut off, I took it to the dealer and they had it fixed? Well this season we were running the A/C and it seemed to be working great. At night I turned the fan to Low and went to bed, during the night the compressor would cycle on for a few seconds and then back off for a minute or two then the compressor would come back on for a few more seconds. This went on and on and on and the whole night, well until I finally got tired of listening to it cycle so I just shut it down, oh, by the way the fan never shut down...
The next morning I called the A/C Company (can't remember who they are, sorry?) He told me the reason the fan never shut down was because maybe the coils were frozen and the fan was trying to de-thaw them???? He told me to run the fan at high speed (which I did) and the fan will have enough power to de-thaw the coils and it would then shut down when the compressor did, and it did... So my question is... WHAT was that all about?? He also told me i could put a few strips of electrical tape over the little temp sensor within the t/s, he said it may be to touchy... I would like to replace the t/s but he said i would need a 7.5 volt model because they don't run off of 12v???? I have read a few post regarding changing the t/s but I don't know if I trust myself to it, they said you need to buy some type of switch from Radio Shack to make the fan work, I'm just not very good with electronic's... Does the cycling on and off thing sound correct to any of you, and should you not be able to run on the low speed if you want, and still have the compressor and fan shut down together? thanks..


Tommy

If the fan is on low, and the humidity is high, the coils can freeze up if the compressor runs for a long time. I've had that problem with several other RV's also.

Tom, I've never had the problem you've described and it doesn't sound normal either. I don't know beans about A/C either. I did the Hunter install with the fan switch and it's pretty straight forward. I suggest you get back with your dealer and explain the situation to him and also tell him of your discussion with Dometic.

Another thing that will cause coils to freeze up is poor electric from the campground.

We've had ours freeze up as well when we were camped next to a lake. We had ran the AC on low for most of the day. When the humidity came up in the evening, it acted exactly as you describe by cycling. We just turned it off for awhile (to thaw) and it was fine. Haven't had any issues since, but haven't been in that type of humidity or ran it on low all day again. I wouldn't have known about the freezing coil issue had someone not posted it here. We also confirmed with Dometic that it wasn't an AC issue.

There is a metal divider between the Intake side and Discharge side.

If the Cold air that should flow into the duct work... is allowed to return to the warm air side... that along with the high humidity can freeze the Coils. There is a small round sensor that should be attached to the center of the coils.. this sensor is there to protect the A/C unit should it start to freeze up.

This divider should be checked by looking at it... to see if there is a gap that would allow the air to circulate inside the A/C. This metal wall is held in place with double sided foam tape. I suggest using a metal duct tape to carefully seal any air leaks... and while your inside the ceiling cover... use this same metal duct tape to smooth the openings to the ceiling duct work. This will help the air flow in each air duct.

Do a search on A/C mods...

Tom
From your description I would say when you turned the fan to low for the evening you didn't have adequate air across the coil and this would cause the freeze up. Much like a home a/c with a dirty or plugged filter. As to why the fan continued to run after you shut to unit off not sure about that. Did you have the fan switch to auto or on. If on the fan would run until you shut the unit off. I would recommend when using the a/c only run the fan on high.

I installed the Hunter thermostat WITHOUT the low speed toggle switch. In my opinion running any A/C on low speed it asking for freeze up troubles. In the ag business I have seen more than my share of freeze ups caused from turning down the fan speed. If you don't want it as cold just turn the thermostat up a bit and don't lower the fan speed.

Have a couple questions,could use some help do i need to to use a low profile air conditioner in the bedroom because of heigth of trailer? also do i need a ducted or non ducted in bed room? I didn,t know if it hooks in duct work. and finally does the non thermostat models fan shut off or do they run non stop when unit reaches temperature? thanks jim thomas

Have a couple questions,could use some help do i need to to use a low profile air conditioner in the bedroom because of heigth of trailer? also do i need a ducted or non ducted in bed room? I didn,t know if it hooks in duct work. and finally does the non thermostat models fan shut off or do they run non stop when unit reaches temperature? thanks jim thomas

1. I WOULD USE THE LOW PROFILE IN THE BEDROOM BECAUSE OF THE HEIGHT.
2.YOU DO NOT NEED A DUCTED IN THE BEDROOM, IT IS TOO SMALL. IT WILL FREEZE YOU OUT IN THAT LITTLE ROOM.
3. IT WILL RUN ALL THE TIME. I WOULD PAY EXTRA TO GET THE THERM. MODEL.

A/c problem Compressor on and off same problem

New Big Country 2009 1st camping trip
I Knew I'd someone that has the same problem...
I replaced the thermostat.. that did not fix the problem.
I figured it was a sensor on the coils.. Looks like I'll be going back to the dealer..

It would work ok if I shut it off for a while..

HI Bernie,

Kinda sounds like your unit may be freezing up if it works OK for a while.
There is a temp sensor in the air intake side that should be cliped to the coils about 1/2 up. These have been known to come loose (mine did) and the unit will work OK for a while the freeze up.. then you shut it off for a while and turn it back on and it works again.

Jim M