26DBH AC Strange Behaviors

[justkdue]

We have a 2016 Cherokee Grey Wolf LTD 26DBH and have been seeing strange behaviors with the Dometic AC recently to the point where it almost is not working at all now.

We have a permanent site. When we arrive on Friday, it is pretty warm when we open things up, we turn on the AC and set temp to 75 and fan to auto to bring things down to temp. After that has settled in, we usually run the AC between 72-75 depending on if we are "in for the night" or just "keeping it cool for the puppy" if we are out. The past few weeks, the unit would only run for about 30-40 minutes (and it was cooling just fine) and then all at once it would shut off for no apparent reason. The only way to get it to come back on turns out to be turn the thermostat OFF, let it sit for several minutes, and then when we turn it back on it will come on.

This past weekend it did about 30 minutes the first time, and then after that would only go about 5 minutes without shutting off - several times. I stopped trying to use it because I don't want to damage things - but obviously it's summer and we need / want the AC to run.

I have cleaned the inside (spongy) filter to make sure that was not the problem. I have also looked for any visual obstructions (none) from the inside. Went on the roof with a camping neighbor, we removed the cover and inspected the fins / coils area - nothing unusual looking there (not full of leaves, dirt, debris, etc. - in fact neighbor commented that it seemed unusually clean for having been in use over three seasons now). Also, I was asked if it had "frozen up" - frankly I didn't see that, but not sure I checked it soon enough after use to have seen that - I suppose it could have frosted up and melted off already by the time I checked.

I'm not an AC guy - not handy with things like that, I'm a computer guy. If this were a computer, I would say it sounds like it is overheating and some type of safety is shutting it down to prevent damage - but just a guess on my part.

Anyone have a similar situation that might offer suggestions what else to check? If need be, this may have to turn into a service call (visit) because I don't think we want to go the rest of the summer with no AC.

Thanks for any feedback.

[KeithInUpstateNY]

I've seen posts about this problem several times, though I haven't experienced the problem myself since I'm in upstate NY near the Canadian border and we seldom need AC.

Here is one such thread I found with a Google search: https://www.google.com/url?sa=t&sour...r1cM3vbjX1OB4W

Based on what I read in this and other threads, if your unit isn't freezing up, check for an obstruction in the air flow. I'm sure you want the cold air distributed throughout your trailer, but have you tried running it with the dump louvers open? If it runs with them open then it could be an obstruction in one or more of your ducts.

[Tacky]

I've not had to work on a Dometic but I did get involved with my Coleman Mach AC unit. I did not find any electronics that would cause it to operate in the manner you describe. I'm wondering if you don't have a thermostat problem. If you have the install manuals for the thermostat and the AC unit, you should be able to test the signal from the thermostat to the AC unit to see if it is there when your AC does not come on.

[rsb201]

Originally Posted by justkdue

We have a 2016 Cherokee Grey Wolf LTD 26DBH and have been seeing strange behaviors with the Dometic AC recently to the point where it almost is not working at all now.

We have a permanent site. When we arrive on Friday, it is pretty warm when we open things up, we turn on the AC and set temp to 75 and fan to auto to bring things down to temp. After that has settled in, we usually run the AC between 72-75 depending on if we are "in for the night" or just "keeping it cool for the puppy" if we are out. The past few weeks, the unit would only run for about 30-40 minutes (and it was cooling just fine) and then all at once it would shut off for no apparent reason. The only way to get it to come back on turns out to be turn the thermostat OFF, let it sit for several minutes, and then when we turn it back on it will come on.

This past weekend it did about 30 minutes the first time, and then after that would only go about 5 minutes without shutting off - several times. I stopped trying to use it because I don't want to damage things - but obviously it's summer and we need / want the AC to run.

I have cleaned the inside (spongy) filter to make sure that was not the problem. I have also looked for any visual obstructions (none) from the inside. Went on the roof with a camping neighbor, we removed the cover and inspected the fins / coils area - nothing unusual looking there (not full of leaves, dirt, debris, etc. - in fact neighbor commented that it seemed unusually clean for having been in use over three seasons now). Also, I was asked if it had "frozen up" - frankly I didn't see that, but not sure I checked it soon enough after use to have seen that - I suppose it could have frosted up and melted off already by the time I checked.

I'm not an AC guy - not handy with things like that, I'm a computer guy. If this were a computer, I would say it sounds like it is overheating and some type of safety is shutting it down to prevent damage - but just a guess on my part.

Anyone have a similar situation that might offer suggestions what else to check? If need be, this may have to turn into a service call (visit) because I don't think we want to go the rest of the summer with no AC.

Thanks for any feedback.

Same problem on my 2019 alpha wolf. Ended up taking to the dealer under warranty and they found the baffles above the foam filter were not secured with duct tape and was basically recirculating the cold air back in the unit and freezing up and shutting itself off. Next time I went camping I couldn’t believe how much more air was coming out the registers and the rv was like an ice box. I suspect you have the same situation going on.

[rwhit]

There is a freeze stat/ 10K ohm thermistor on the unit I have. It is just above the filter behind a metal cover. It connects to the control board (2 wires) that could possibly be the issue. In commercial unit these tend to go bad quite often. There are resistance charts for 10K ohm sensors on line. If you find the sensor connection on the board and have an ohm meter you can check it. I know off the top of my head when the sensor is around 70 -71 degrees it will read 10k ohm. If you need the chart let me know and I can look it up tomorrow and send you the link as I have it saved on my work computer. I have to send it to my technicians all the time.

[justkdue]

Well, the good news is THIS weekend we have had AC almost all weekend - full on cooling with good temperature and no shutdowns AFTER I changed a setting on Friday evening.

I got to thinking back and retracing my steps to previous weeks - when did this start happening, and what was I doing different? It was then that I realized the problems I was having started when I tried to manually control the fan settings.

We had a couple of nights where we had company, and as such had closed the bedroom doors not thinking about the result that would happen - the AC cooled the main area and then turned off at temp but the bedroom wasn't getting cool (thermostat is in the main living area) - so I had changed the fan setting to "low" instead of "auto" thinking that would keep the air circulating all of the time instead of only when the compressor kicked on... in hindsight, that is when the problems started.

This weekend, I experimented a little with that setting - if I leave it on "low" the unit will work, cool down the camper, and then shut down and won't come back on (at all) until I power cycle the thermostat with a few minute "break" in between. I didn't try it on high because I don't want that 24/7 anyhow. So then I set the fan back to "automatic" and for the rest of the weekend the unit has been cycling on and off as needed per temperature setting "normally" (what I'm used to). From time to time it will turn off completely, or, sometimes after temp stabilizes it switches itself to low fan for a while - but the AC is definitely cooling.

So now I'm thinking maybe the only problem is with whatever determines how the fan setting responds? I may still have a problem, but I definitely do not have a "no AC" problem.

As a side note, I did try to check the things others referenced above, but essentially all else seems OK.