Yet another AC question - Montana Owners Club

kozzy · 08-05-2016, 03:36 AM

I know there a are a few AC topics going on, but my issue now is a little different than the others...
So after finding out the correct way my AC's run, they have been working good for the last few days. I am currently in the Outer Banks, been hot here the last few days. Have both thermostats set at 70, coach seems to stay cool, will get down to about 73, not bad for being in direct sun, on the beach, I think anyway. At night, they have been cycling off because it has been staying cool in here. Now, my front AC, will cycle off, but will not cycle back on. Set at 68 for testing, and I checked it yesterday and today, was 73 up there. I had to turn the unit off, wait a few minutes, then back on again. It would kick on. After a little while, I'm assuming when temperature was reached, it would cycle off, and once again, would not cycle back on when needed. Got up to 73 again, I had to shut it down and turn it on again. This happened in the middle of the night the last 2 nights, up till then, it has been working fine, since this past Sunday. It only happens with my front AC, my rear AC has been fine. Any ideas? Also, one thing I noticed this morning is while the front AC was on, it turned off for about 10 seconds then back on again. That has happened before with the rear AC on previous trips. Not sure why that happens. Nothing is frozen up at all...

dieselguy · 08-05-2016, 04:04 AM

Recently there have been a number of thermostat issues concerning dual zone air not only on the MOC, but other SOB sites as well. This is just a guess, but the thermostat is what controls when the compressor cycles. Granted the compressor has its own thermal cutoff device, but it doesn't sound as if this comes into play in your case since it seems to cool right up to when the thermostat reaches set temp. There doesn't seem to be any call for start up once it cycles off unless you switch it off and back on. You might get out the manual and do a system reset just for grins an giggles or remove the thermostat from the wall and check connections.

kozzy · 08-05-2016, 04:32 AM

I don't have the Dual Zone thermostat, I have 2 single zone thermostats. I have already checked the connections, all seems well. Its weird that it was fine for a few days then started happening. It happened a few weeks ago, same deal, was fine for a few days, then would not cycle back on.
Thermostat or control board for the second AC I am guessing. I called CW, and as suspected, their service tech was wrong. He told me the second thermostat upstairs was just on/off, and that it would not cycle the AC based on temperature. After calling Dometic and Keystone, I confirmed that the CW tech was wrong, and it is in fact supposed to cycle based on temperature. I'm going to have to get it looked at I am guessing after this trip. There is a dometic service center right down the road from me, I think I might give them a try since CW obviously doesn't know their own products that well.

dieselguy · 08-05-2016, 05:10 AM

Although there are a few on the MOC that give high marks for a given CW ... you'll find just by word of mouth that any dealings with CW in general results in disappointment. Chaos is an excellent adjective for most of their service departments. Anyways ... no matter how many thermostats you have, I'd put my first guess there.

Bama Camper · 08-05-2016, 02:04 PM

I had a problem with mine, with the same set of symptoms as yours.... it would cycle off after the thermostat was satisfied, but would not cycle back on without a "reset". The reset was to turn the system off, wait a few seconds, then turn it back on. The only other symptom you didn't mention that I noticed was when the thermostat turned the AC off, it did NOT go through a "blow down" period where the compressor went off and the fan continued to run for 20 seconds or so. After the repair, it does go through a "blow down" period.

Unfortunately, the repair was a replacement of the thermostat.

Good luck.

kozzy · 08-06-2016, 04:38 AM

Thanks Bama ill mention that when I call the service center after I return home from my trip.
getting to be a pain to keep going in and resetting the AC

Mike Sutton · 08-06-2016, 06:07 AM

I had the same problem and figured out the it will not recycle back on if the Fan is set to Auto or Lo.. Reset the fan speed to Hi and it works fine. Don't know if this is by design or a fault thermoastat but regardless it fixed my problem.

kozzy · 08-06-2016, 07:21 AM

If I leave the fan set to HI then the fan will run constantly. The compressor will kick on and off I believe but the fan stays on. Bringing in humid air. The domestic service guy said you are supposed to leave it in AUTO so it all cycles on and off as necessary.

dieselguy · 08-06-2016, 08:26 AM

It's running the way it's supposed to. With the fan on auto ... the entire A/C unit will cylce on and off. When you place the fan on high ... the compressor cycles but the fan stays on high continuously. Normally your A/C draws air in from the cabin, not the outside air. If you definitely feel warm humid air blowing when the compressor is off ... you may have an air leak in your return air somewhere drawing air from inside the attic. I have seeen a retun duct come untaped from the A/C unit itself causing it to suck the hot air from the attic instead of from the cabin. Despite what the service guy said ... many of us leave the fan on high in warm humid weather to keep the evaporator coil from icing up. None the less this observation is different from your earlier observation of the compressor not starting back up after the first cycle.
Mike ... the compressor should cycle on and off as the thermostat calls for it to do so no matter what fan selection you make.

kozzy · 08-06-2016, 09:12 AM

I'm wondering if I felt warmer air because even in HIGH the compressor was not cycling like it should, indicating there is still a problem.
Strange that it all worked fine for a few days then the problem started. But this happened a few weeks ago same thing worked OK the. Didn't.
Something def not right , I though it might have been iced up but climbed on the roof and checked and it was all fine. Right now it's running fine casue I have it set to 65 and it's not going To hit that. Just have to get it checked. Service guy thinks it's the controller in the AC or thermostat. I'll pass all this info to him. Been a big help

dieselguy · 08-06-2016, 09:28 AM

Just to clarify things about icing ... when you get on the roof and look at your A/C with the bonnet still on, the coils to the rear are condensor coils ... they are not the ones that ice up. With the bonnet off, there will be a box with silver insulation foil covering it towards the front. Inside is the evaporator coil ... this is what ices up. On the older A/C units with the return grill right in the middle of the ceiling ... when you removed the grill and filter, you looked right at the evaporator coil. It was easy to see if any icing was happening. With the whisper quiet A/C's there is no inside ceiling grill directly beneath the A/C unit.

kozzy · 08-06-2016, 09:45 AM

Yeah I pulled the cover off to make sure. Thanks for the clarification though. If I hadn't known I would be going up to look again lol

jameswbarton · 08-06-2016, 02:49 PM

One of my AC units was erratically cycling. I have the two AC configuration with single zone thermostats. I found my issue. The thermostat in the kitchen was mounted on the wall adjacent to the bath. The hole in the non insulated wall was very large. The sensor was directly over the hole. I insulated the hole with foam and put electrical outlet insulation between the thermostat and wall. The thermostat is now sensing air temp instead of the interior wall temperature and it is no cycling properly.

kozzy · 08-06-2016, 05:43 PM

Hmmm perhaps I should check that. The thermostat in the bedroom is installed on the wall adjacent to the bath. I know there is not any insulation there
L have to look into that when I get home. Again love the forums. Thanks for the tips all around. I have always found useful answers and hopefully gave some as well.

Bama Camper · 08-08-2016, 04:29 PM

Quote:

quote:Originally posted by jameswbarton

One of my AC units was erratically cycling... The thermostat in the kitchen was mounted on the wall adjacent to the bath. The hole in the non insulated wall was very large. The sensor was directly over the hole. I insulated the hole with foam and put electrical outlet insulation between the thermostat and wall. The thermostat is now sensing air temp instead of the interior wall temperature and it is no cycling properly.

kozzy - I also had this problem also, but didn't mention it because, well... one problem at at time!!

In my case (when I got the thermostat replaced from the first problem), I noticed mine was also mounted over a very large hole in the empty wall where the wire came out (I guess a larger hole was easier for them to fish the wire out of). When I removed the thermostat, I noticed warm air coming out of the hole! In Keystone's wisdom, in the 305RL model, they mounted the converter in the basement with the exhaust fan directed directly up the void in the wall. Like jameswbarton did, I stuck some insulation in the hole behind the thermostat, but also up into the wall from the bottom, behind the converter. Also, just to be sure I didn't have any infiltration from warm air through the insulation, I duct taped behind the thermostat before remounting it to the wall. So, your unit may be like mine - you may want to check the location of the converter in the basement, and note the direction of the exhaust fan flow.

Don't you just love the engineering behind some of the systems in our RVs?

kozzy · 08-10-2016, 03:03 PM

Yeah and I love that after every trip so far this year with my brand new unit I'm fixing something.
I plan to look at the hole as soon as I can. My converter is not in line with the wall where the thermostat is mounted so I don't think the exhaust is the issue but I'm going to remove the panel in my storage area and give it all a good look

jameswbarton · 08-10-2016, 04:40 PM

Kozzy why are you fixing it and not Keystone Warranty? Of course at this time if I call a dealer I get an appointment in a few months but if you can get a good rep at Keystone they will convince a local dealer to see you sooner. The on hold time for Keystone is about an hours during the daytime.

kozzy · 08-10-2016, 05:17 PM

its not that they wont fix it, just easier to do most of it myself, instead of taking th them, dropping for a few days then picking back up. This last piece that broke was one of the wood trip pieces on my bedroom slide. if fell apart. Took the pieces in the basement, nail gun and glue, and 30 minutes later its fixed and probably better then the dealer would do. and took less time then to drive it to the dealer and drop off. Its just easier sometimes depending on the issue. The last few issues have just been trim coming loose or off. Take a finish nailer out to the unit and my compressor and a few POPS and all is good as new. I have taken it in for stuff that is above what I can do, for instance when my slide broke and needed to be welded, that's something they can handle.
As far as my AC, they told me at CW that the way it was working is normal, shows what they know. if they think that is normal then they will never find the issue and fix it. s long as it doesn't cost me any money to fix small issues I just do it.

Bryfast · 08-17-2016, 11:41 AM

Kozzy. Have you had this problem resolved? I have a 2016 3710fl with the same problem. Would like to try and fix it myself. I live in Georgia but I bought my fifth wheel in Iowa. So all of the dealers don't want to work on it since I didn't buy from then.

kdeiss · 08-17-2016, 12:47 PM

Quote:

quote:Originally posted by Bama Camper

I had a problem with mine, with the same set of symptoms as yours.... it would cycle off after the thermostat was satisfied, but would not cycle back on without a "reset". The reset was to turn the system off, wait a few seconds, then turn it back on. The only other symptom you didn't mention that I noticed was when the thermostat turned the AC off, it did NOT go through a "blow down" period where the compressor went off and the fan continued to run for 20 seconds or so. After the repair, it does go through a "blow down" period.

Unfortunately, the repair was a replacement of the thermostat.

Bama Camper I am having the same problem has the Themostat replacment fixed the problem long term?

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