BAC Forum

General Boards => Technical Support => Topic started by: LaMonte Monnell on August 29, 2022, 04:53:59 PM

Title: Rear a/c issues
Post by: LaMonte Monnell on August 29, 2022, 04:53:59 PM

I have a rear dometic a/c unit. The output is great and working right.
The issue I have encountered recently is its not shutting down completely.
After it cycles it still hums like its not turning all the way off like something is sticking.
Would this be a capacitor issue or something else. Most of the time it is ok, but does this non shutdown sporadically. I turn the a/c breaker off and wait a bit , turn it back on and its fine.

Title: Re: Rear a/c issues
Post by: Bill Lampkin on August 29, 2022, 05:04:10 PM

Could be your tstat fan setting is set to run all the time. Tstat Fan setting set to auto will only run when A/C is on. See if the fan setting is set to Hi or low. 

Title: Re: Rear a/c issues
Post by: LaMonte Monnell on August 29, 2022, 05:13:11 PM

thermostat is set to auto and fan setting is on high......

Title: Re: Rear a/c issues
Post by: Bill Lampkin on August 29, 2022, 05:21:46 PM

Set the fan setting to auto.

Title: Re: Rear a/c issues
Post by: LaMonte Monnell on August 29, 2022, 06:04:02 PM

Thermostat is set to auto and fan has a high or low setting... i have it on high.

Title: Re: Rear a/c issues
Post by: Bill Lampkin on August 30, 2022, 12:24:07 AM

My suggestion applies to the newer Dometic 10 button thermostat. Yours may be different (5 button). We had to replace both tstats a few years ago when we put in new A/C units.

Title: Re: Rear a/c issues
Post by: Michael DeFalco on August 30, 2022, 01:05:15 PM

you state its not shutting off all the way ?  is it still moving air ? or is it just making a noise ?

Title: Re: Rear a/c issues
Post by: LaMonte Monnell on August 31, 2022, 04:20:32 PM

It just makes a humming noise like its not completely shutting off.
It is an intermittent issue that just happens occasionally. I have to turn the rear a/c breaker off to get it to stop.
Then usually its ok when I turn the breaker back on.

Title: Re: Rear a/c issues
Post by: Eric Maclean Co-Admin on August 31, 2022, 07:49:57 PM

Lamounte
Not sure whether the hum you describe is the fan motor trying to start or the compressor running either way it would likely be a fault in either the thermostat or the control box . My guess would be a sticking relay in the control box

Eric

Title: Re: Rear a/c issues
Post by: LaMonte Monnell on September 08, 2022, 06:47:26 PM

thanks Eric.