Yet another AC question

[Bama Camper]

quote:Originally posted by kdeiss
Bama Camper I am having the same problem has the Themostat replacment fixed the problem long term?

Yes, it has. Mine operates as designed now. In the AUTO mode, when the room temp is >5 degrees higher than the set point, the compressor turns on and the fan runs on high. When the room temp is

[kdeiss]

Bama thanks for your prompt reply,this afternoon I changed the temp diferential from 2 degrees to 1 Degrees fan in Auto. The unit has been working perfectly cycling on and off I will monitor.When and if it starts to perform as you discribe I will replace stat!
Thanks
Ken

[kozzy]

I haven't solved it yet, I'm planning on tackling it with all the ideas here when I get my unit back from camp I'm going this weekend and bringing it back with me Monday. I plan to remove both thermostats and insulate behind them, and I am also going to change the temp differential as well. I really don't think it is a thermostat issue, from what I am seeing here, it looks to be the install and set up. I am going to try this stuff first anyways.

[Bama Camper]

quote:Originally posted by kdeiss

I changed the temp diferential from 2 degrees to 1 Degrees fan in Auto.

Huh? Changing the differential is just for the furnace mode isn't it? The >5 and

[kozzy]

ill start with the insulation , I can do that without taking it in for service.
Next step will be the thermostat. Its going to be tough, because it will work fine fore a few days before it starts to screw up.
I would think if it was a bad thermostat it would not work properly right from the start.

[kdeiss]

quote:Originally posted by kozzy

I haven't solved it yet, I'm planning on tackling it with all the ideas here when I get my unit back from camp I'm going this weekend and bringing it back with me Monday. I plan to remove both thermostats and insulate behind them, and I am also going to change the temp differential as well. I really don't think it is a thermostat issue, from what I am seeing here, it looks to be the install and set up. I am going to try this stuff first anyways.

Yes you are correct for furnace mode only!
This Am I moved temp setting down a degree AC came on cycled off.Then I noticed it is hot in here checked temp was 80 I turned off Thermostat and then back on AC is now running just ordered a new Stat
Thanks for your help
Ken

[Bama Camper]

Keep us posted...

[kdeiss]

Will do Bama........ Last night the unit was cycling perfectly!
I am concerned if not the thermostat it may be the control box!

[kozzy]

A dometic Service guy told me its one or the other, Thermostat or controller on AC. He recommended I try swapping my Thermostats to see if the problem moves rto my rear AC, if it does, then bad thermostat. I'm hoping to try all this when I get my until home Sunday afternoon. My thing is, 3 weeks ago, I had it in my driveway plugged in, with the front AC on, and it worked as supposed to . Cycled on and off, for days. Went on my next trip to OBX, and the first few days worked like it was supposed to, on the last few days, the problem returned. I don't understand why it worked for OK for a dew days and then change. If I take to a dealer, im afraid ill get the WE COULDNT DUPLICATE THE ISSUE speech...

[kdeiss]

quote:Originally posted by kozzy

A dometic Service guy told me its one or the other, Thermostat or controller on AC. He recommended I try swapping my Thermostats to see if the problem moves rto my rear AC, if it does, then bad thermostat. I'm hoping to try all this when I get my until home Sunday afternoon. My thing is, 3 weeks ago, I had it in my driveway plugged in, with the front AC on, and it worked as supposed to . Cycled on and off, for days. Went on my next trip to OBX, and the first few days worked like it was supposed to, on the last few days, the problem returned. I don't understand why it worked for OK for a dew days and then change. If I take to a dealer, im afraid ill get the WE COULDNT DUPLICATE THE ISSUE speech...

Kozzy that is exactly what my unit is doing I have an extended warrinty like you I concerned that when a tech looks at it the problem will not be duplicated.

[kozzy]

how did you order the new thermostat? Did you just tell someone it was broke or call Dometic directly? Id love to just get a new one and install it instead of going through the hassle of them telling me they cant duplicate the issue...

[rohrmann]

I had my Dometic CCC2 thermostat fail last year and ordered a new one from Dyers, www.dyersonline.com It came pretty quick and with shipping, was a little over $100. A couple years ago, we had the front A/C start acting really strange, so shut it off and just ran the main one. After some investigating, I opened up the cover on the control box above the ceiling vent, and found the circuit board had corrosion over most of it. I replaced the control box and everything was working again.

[kdeiss]

quote:Originally posted by kozzy

how did you order the new thermostat? Did you just tell someone it was broke or call Dometic directly? Id love to just get a new one and install it instead of going through the hassle of them telling me they cant duplicate the issue...

I purchased from Amezon out of pocket Dometic 3313192.000 $35.38 INCLUDING FREIGHT

[Bama Camper]

Don't you just love intermittent problems? After a career working in electronics, that's the reason I don't have any hair left (well, one reason). It's the bane of every engineer.

Kozzy, the swap of the thermostat as a troubleshooting technique is valid. However, if Murphy has his way (and he usually does), when you swap the thermostat, then swap it back, both units will then work... at least for a while!

If it ain't broke, you can't fix it!

Kozzy and Kdeiss - Since the problems seem to be intermittent, just to be sure, ascertain that your 12 volt supply and battery are up to snuff. I suspect those thermostats are pretty sensitive to a low voltage supply, or ripple on the 12 volt line caused by a bad battery and a converter that puts out a lot of AC ripple (the battery tends to "filter" the ripple of a overburdened converter). Make sure there isn't any correlation between the thermostat acing up and a big load on the 12v supply like a lot of lights on, etc.

[kdeiss]

New thermostat arrived this Am I have installed has made one on off on cycle! Well as they say "lets see what happens"
This unit was replaced under Warrinty after 8 months of service.
I did something I do not do normally I purchased a 2 year extended Warrinty from Dometic.

[kdeiss]

[quote]Originally posted by kdeiss

New thermostat arrived this Am I have installed has made one on off on cycle! Well as they say "lets see what happens"
This unit was replaced under Warrinty after 8 months of service.
I did something I do not do normally I purchased a 2 year extended Warrinty from Dometic.

Thermostat did not solve the problem! I have Identified the reason the unit is shutting down because it is Iceing as it is designed to do!
Was Dam hot here yesterday.
This Am i started the unit set temp at 74 inside temp 76
Checked temp at vents 49 degrees inboud to the AC 68 perfect should be a 20 degree diferential I will check temps through out the day

[jameswbarton]

If you are icing you have low air flow through the coils. Are all of your registers open and ducts clean? Are your coils in need of cleaning.

[kdeiss]

quote:Originally posted by jameswbarton

If you are icing you have low air flow through the coils. Are all of your registers open and ducts clean? Are your coils in need of cleaning.

All the above is A OK?... When it gets 80 and above the unit never shuts off! Have been running fan on high not Auto all lights are LED VERY LITTLE HEAT, have been cooking out side. vent and fan on when showering

[kozzy]

I'm pretty sure mine was not icing up......ill keep on eye on it. I brought the unit home from camp today, so ill be doing some work tomorrow, going to start with insulation.
BUT Friday night, at camp, I had it set to 68, internal tempo was 66...set it to auto, t didn't turn on, at some point in the night though , it kicked on.
So it does work, and I'm thinking its not the thermostat, I think it is something screw fooling it, or, maybe it did ice up those few times I had the issue, and I just didn't notice. Ill prob do some things tomorrow, and wait until it happens again and double checking the icing, etc.
As for the 12v, no abnormal 12V loads, but ill pay attention to that as well.

[Bama Camper]

Sorry to hear the thermostat didn't fix the problem where the unit would not turn back on after it turned off. It was the thermostat in my case.
Are you saying the unit shuts down BECAUSE it is icing? That would make sense if the unit has an "icing sensor".

Check the sheet metal piece between the intake and output side. That has been a problem that causes icing for several folks here (mine included). The sheet metal dam on mine had fallen down in transit. A service tech shot a couple of sheet metal screws in it to hold it up and also sealed the edges with aluminum tape. He said it was a common problem with Dometic units of my vintage. You have to remove the filter door, then unscrew the plastic frame to get to it. Operate the AC and you can see how the intake side is separated from the output side. Look for leaks and wiggle the sheet metal dam up there to see if it is intact.