AC shut down but restarted later

[larry2c]

I've seen a lot of threads regarding issues with the Dometic AC units and I'm wondering if this is how it starts. We got set up at the CG and once we plugged into shore power I turned on the AC. It was in the low 90's outside so I left the AC run while I did some work around the trailer (this was our maiden voyage with our Salem 210RBXL). It had been running about 4 hours when it just shut off. I cycled through the thermostat control (off, just fan, back to AC) and no change. I checked the circuit breaker and it wasn't tripped but I tripped it and reset it just to be sure. Still no change.

I let the unit sit for maybe 20 minutes then tried it on just the fan mode - the fan started running so I switched to AC and it started the compressor and cold air started blowing. I left it run until it cooled down that evening and had no further issue that day.

The next day I had it running and everything was working fine until I looked over at the thermostat at some point and noticed it was showing 79 degrees. On closer inspection I saw that it was now in heater mode - but the AC was still blasting cold air AND the furnace was on (blowing air out the heater ducts). I switched the thermostat back to AC mode and the furnace blower shut down and the AC behaved properly the rest of the day.

Needless to say, with the threads I've seen about AC failures and my first trip out having weird things going on with the AC I'm wondering if this is how the failure begins. Anyone have something like this happen to their unit?

[Schvarak]

Originally Posted by larry2c

I've seen a lot of threads regarding issues with the Dometic AC units and I'm wondering if this is how it starts. We got set up at the CG and once we plugged into shore power I turned on the AC. It was in the low 90's outside so I left the AC run while I did some work around the trailer (this was our maiden voyage with our Salem 210RBXL). It had been running about 4 hours when it just shut off. I cycled through the thermostat control (off, just fan, back to AC) and no change. I checked the circuit breaker and it wasn't tripped but I tripped it and reset it just to be sure. Still no change.

I let the unit sit for maybe 20 minutes then tried it on just the fan mode - the fan started running so I switched to AC and it started the compressor and cold air started blowing. I left it run until it cooled down that evening and had no further issue that day.

The next day I had it running and everything was working fine until I looked over at the thermostat at some point and noticed it was showing 79 degrees. On closer inspection I saw that it was now in heater mode - but the AC was still blasting cold air AND the furnace was on (blowing air out the heater ducts). I switched the thermostat back to AC mode and the furnace blower shut down and the AC behaved properly the rest of the day.

Needless to say, with the threads I've seen about AC failures and my first trip out having weird things going on with the AC I'm wondering if this is how the failure begins. Anyone have something like this happen to their unit?

Have you done a thorough reading of the owner's manual? And followed the instructions completely?

[N6ZCM]

Originally Posted by larry2c

I've seen a lot of threads regarding issues with the Dometic AC units and I'm wondering if this is how it starts. We got set up at the CG and once we plugged into shore power I turned on the AC. It was in the low 90's outside so I left the AC run while I did some work around the trailer (this was our maiden voyage with our Salem 210RBXL). It had been running about 4 hours when it just shut off. I cycled through the thermostat control (off, just fan, back to AC) and no change. I checked the circuit breaker and it wasn't tripped but I tripped it and reset it just to be sure. Still no change.

I let the unit sit for maybe 20 minutes then tried it on just the fan mode - the fan started running so I switched to AC and it started the compressor and cold air started blowing. I left it run until it cooled down that evening and had no further issue that day.

The next day I had it running and everything was working fine until I looked over at the thermostat at some point and noticed it was showing 79 degrees. On closer inspection I saw that it was now in heater mode - but the AC was still blasting cold air AND the furnace was on (blowing air out the heater ducts). I switched the thermostat back to AC mode and the furnace blower shut down and the AC behaved properly the rest of the day.

Needless to say, with the threads I've seen about AC failures and my first trip out having weird things going on with the AC I'm wondering if this is how the failure begins. Anyone have something like this happen to their unit?

Well that sounds like a thermostat problem more than a AC unit problem!

I would have the thermostat checked out, or rest it factory default if that is possible.

[Schvarak]

Think he's not doing the RTFI properly. I have a feeling there's nothing wrong with it--AC or thermostat. Just needs to learn how it works!

[larry2c]

I have read the manuals (all of them) and I'll be reviewing them again to see if I missed something. Maybe I wasn't clear in stating what happened. The first time it stopped blowing the thermostat was set to 70 and according to my little weather station it was 80 in the trailer. Also, it would not run in fan mode which should run no matter what the temperature is.

In the 2nd instance the thermostat had been set at 72 and in AC mode. Nobody was in the trailer but me and I didn't touch the thermostat so unless it can switch from AC mode to Heat mode by itself, it should not have been in heat mode.

I guess we'll see what it has in store for us today - looking at another day in the 90's so it should get some exercise...

N6ZCM - that is a possibility and the thermostat seems pretty "cheesy" compared to the one in our house

[Schvarak]

A couple things missing from your reply. You mention fan mode, you didn't mention what fan setting you selected. It should be auto not low or high. The fan running continuously tells me you have it low or high. Need to make sure the thermostat is set to cool or heat, depending on what your trying to use.

[Stovebolt]

Originally Posted by larry2c

I've seen a lot of threads regarding issues with the Dometic AC units and I'm wondering if this is how it starts. We got set up at the CG and once we plugged into shore power I turned on the AC. It was in the low 90's outside so I left the AC run while I did some work around the trailer (this was our maiden voyage with our Salem 210RBXL). It had been running about 4 hours when it just shut off. I cycled through the thermostat control (off, just fan, back to AC) and no change. I checked the circuit breaker and it wasn't tripped but I tripped it and reset it just to be sure. Still no change.

I let the unit sit for maybe 20 minutes then tried it on just the fan mode - the fan started running so I switched to AC and it started the compressor and cold air started blowing. I left it run until it cooled down that evening and had no further issue that day.

The next day I had it running and everything was working fine until I looked over at the thermostat at some point and noticed it was showing 79 degrees. On closer inspection I saw that it was now in heater mode - but the AC was still blasting cold air AND the furnace was on (blowing air out the heater ducts). I switched the thermostat back to AC mode and the furnace blower shut down and the AC behaved properly the rest of the day.

Needless to say, with the threads I've seen about AC failures and my first trip out having weird things going on with the AC I'm wondering if this is how the failure begins. Anyone have something like this happen to their unit?

If the air and heat are running at the same time, then the thermostat isn't set on auto.

[larry2c]

Schavarak - had it on Low because I wanted the quieter operation. I'll put it in auto for the fan speed today and see if there is any difference in behavior.

[Schvarak]

Aha! As I suspected, you didn't fully RTFM. By the way that means to Read The blank Manual/ Instructions. You missed a whole lot. It will work once you set it to Auto.

[larry2c]

Yeah, RTFM was one of the many useful acronyms I picked up in the Navy. Evidently, reading every word wasn't one of my better attributes. I guess it matches the selective hearing that DW says I have

[Bama Rambler]

If the thermostat changed itself from cooling to heat, then it's the beginning of issues. There have been reports of this before and it turned out to be the beginning of issues. Try initializing the thermostat, and see if it does it again. If it does then it's either the thermostat, control board, or loose/corroded connections between the thermostat and control board.

[larry2c]

I'm looking in my user manual and trying to find how to do a reset. I have the pdf version of what came with the trailer but it doesn't match my actual thermostat - maybe I have an older version? In the picture below it shows the model of thermostat I have (except mine is white). However, the manual shows a round unit with some LED's.

Can anyone point me to the right manual if there is a difference other than the shape?

[Schvarak]

That isn't all that different from mine--just keep tapping the mode thingy until what you want shows up fan heat or cool in fan mode you keep pressing one of the arrows until it says auto. In cool mode, you set the temp you want to maintain. Same for heat mode. Simple isn't it?

[Schvarak]

Originally Posted by Bama Rambler

If the thermostat changed itself from cooling to heat, then it's the beginning of issues. There have been reports of this before and it turned out to be the beginning of issues. Try initializing the thermostat, and see if it does it again. If it does then it's either the thermostat, control board, or loose/corroded connections between the thermostat and control board.

Just lack of knowledge Bama it really wasn't heat running, it was only the fan not on auto and pushing warm, not heated air. AC AND heat can't run at the same time.

[Bama Rambler]

You have the Capacitive Touch Thermostat.

Here is a link to the manual Capacitive Touch Thermostat

Unfortunately I don't see any instructions for initializing it.

[N6ZCM]

I have the same unit, with Dual 15K units in my 2015 FR Sandpiper Park Model on my Oregon property(off grid).
My thermostat is dual zone control, I have never been able to run just the fan on the heater, now the AC units no problem!
I would love to run the fan on the heater when the AC is on, it would suck in all that cold air that sinks to the floor then blow it out the vents to other rooms and such!!
I wonder if I am missing something, but no where in the manual it says how to run the FAN only on the heater system.

There is something wrong with a thermostat if it turns on the heater and AC both at the same time! That should NEVER happen!

I have cat that we have to leave her in our 5th wheel and leave the AC on when hot, and we are out sightseeing... if I thought for 2 seconds that a Thermostat would turn on the heater when I just set it for Cool, it would have been removed and replaced immediately!

35,000 BTU heater plus the warm day will over power any AC unit running.

I think by removing all 12 volt power will reset it.

[larry2c]

Originally Posted by Schvarak

Just lack of knowledge Bama it really wasn't heat running, it was only the fan not on auto and pushing warm, not heated air. AC AND heat can't run at the same time.

Actually I have the ducted AC and the furnace/heater uses different ducts (down by the floor). When the AC is running, nothing comes out the floor ducts. When the system switched to Heat mode, the thermostat showed the heater symbol (wavy lines not the snowflake) and there was air coming out of the heater ducts. So, yes, the heater had come on without anyone touching the thermostat.

[larry2c]

Originally Posted by N6ZCM

I think by removing all 12 volt power will reset it.

I found the "initialize" steps in the manual and did that. We'll see what happens today - and we have furry friends as well (dogs for us) that I would not want stuck in a scorching hot trailer. I will not be leaving them behind for more than a short period until I'm sure this issue is resolved.

[N6ZCM]

Originally Posted by larry2c

I found the "initialize" steps in the manual and did that. We'll see what happens today - and we have furry friends as well (dogs for us) that I would not want stuck in a scorching hot trailer. I will not be leaving them behind for more than a short period until I'm sure this issue is resolved.

Glad you found it!!!
Is it one of those things press and hold buttons, stand on one leg and sneeze!

[Bama Rambler]

Originally Posted by larry2c

...So, yes, the heater had come on without anyone touching the thermostat.

That's what I understood. I bet there's nothing in the manual about that happening.

As I said before, we seen that reported before.