AC won't turn on

[Lincoln]

AC worked at dealer walk thru. I can't get it started and no owners manual was provided. The furnace works and I set thermostat to AC and a high temp. thermostat also didn't work in fan mode. Voltage was 118 volts and Circuit breaker is on. Is there another switch or something else I need to do? Thanks!

[JCR GD]

Since GD probably won't be answering until tomorrow, I'll take a stab at it.

Hopefully you meant a LOW temp to get A/C to come on. Are you on a 30 or 50 amp service and where did you get the 118 volt reading?

Also, is all other AC powered equipment working ( fireplace, microwave, etc)

[Cate&Rob]

I set thermostat to AC and a high temp!

If you provide trailer model and type of AC, specific help is more likely.
As a first guess, try setting the thermostat to a LOW temp to get the AC to come on.

Rob

[Lincoln]

Thanks for the quick feedback. It's a 2017 337RLS, but since there was no owners manual I don't know the brand or model number of the AC unit. The fireplace and microwave work fine. I had 30 amp service and was using a progressive industries surge/voltage protector to read the 118 volts at the camp site service box. I thought I tried a low temp to test the AC, but since I typed high temp, maybe I did. Seems sort of dumb, but since it's pretty cool in Michigan right now, maybe I didn't go to a low enough temperature to activate the AC. I'll be making another overnight test trip this Wednesday and will try again. If anyone knows of other switches that have to be turned on, I'd appreciate a heads up. The fact that it only worked in heat mode and not fan mode also has me a little suspicious.

Thanks again!

[Jerryr]

I assume you have a Dometic AC like my 2017 337.

First see what the thermostat sees as current temperature. To do this hit the left button until you turn off the AC (blank screen). Then hit the up button on the right side and current temp will be displayed. Unit must be off to display current temp

Next hit left button until fan speed is displayed (auto, low or high) then hit right down button until AUTO is displayed.

Then hit left button until cool snowflake on bottom right is displayed putting the system in cooling mode.

Then drop temp with right lower button until temp setting is a few degrees below what was initially read as current temp

About 15 seconds or so the AC fan should start and about 3 seconds later you will hear the compressor kick in.

Hope this helps. And report back.

[lptxtandem]

If you have the Dometic Single Zone Digital Thermostat, then here's the manual.

[huntr70]

The furnace only works in heat mode. It won't do anything in fan modes. There is no high or low fan mode in heat settings.

[Lincoln]

Thanks again for all of the feedback. I'll try this Wednesday when camping and let you all know what happens!

[Lincoln]

AC works! Problem solved.
I wanted to thank you all again for your prompt feedback and let you know what the problem was. As I mentioned before, it worked at the dealership but not when I tried it the first time. It turns out that the AC is incorrectly wired through the auxiliary AC circuit breaker instead of the primary AC breaker and someone with good intentions at the dealership after the demo turned off the auxiliary and turned on the primary AC circuit breaker. So the double faults of it being incorrectly wired and someone flipping the breakers made it harder to solve.
Thanks again for your help.

BTW does anyone know if the 337 has 2 GFI' s? None of the bedroom electrical outlets work. I've only found one GFI on the island and it works.

[Jerryr]

I'm not near my 337 now but I'm not aware of aux and primary circuit breakers.

The 337 uses 50 amp supply. It's actually 2 separate 120 volt 50 amp legs and I suspect each of the 2 legs (circuit) is protected by a separate single pole 50 amp/120v breaker. Not like home 50 amp supplies where the 2 legs are used to supply 240 volts an a ganged double pole breaker is used. There is nothing in your trailer that uses 240 bolts.

I know on mine one AC works off one phase (leg) and the other AC works off the second phase (leg). Perhaps the main breaker that supplies phase that feeds the bedroom outlets is turned off cutting off power to the bedroom outlets.

All circuit breakers should be turned on.