How to stop AC from clicking (attempting to start?)

[GlacierGirl]

We are boondocking and running our furnace at night. The fan, via our Dometic thermostat, is set to AUTO, although we have also run it on low at times. Our problem is that throughout the night whenever the furnace is attempting to ignite, the AC is also making loud clicking sounds, as though it is trying to start, as well. To be clear, the clicking sounds probably aren't loud, but at night they sure seem to be! Argh! Anyway, what do we need to change to stop the AC from trying to do whatever it's doing?

Thanks!

Barb

Edited Friday at 03:23 PM by GlacierGirl
Misspell

[jd1923]

1 hour ago, GlacierGirl said:

Anyway, what do we need to change to stop the AC from trying to do whatever it's doing?

Barb, do you have the Dometic thermostat set on furnace only, or on the heat pump setting. I don't think we have a heat pump, but there is the setting on the thermostat. When I accidently switch to that setting, no clicking, but the fan starts running above. There shouldn't be any signal sent to the A/C when in furnace mode.

If not, could be your thermostat is failing. I've got a possible work-around. Turn the 120VAC breaker off for the A/C. This may keep it from clicking, if it needs the 120VAC to make that noise.

[GlacierGirl]

@jd1923, thank you very much! Our Dometic a/c doesn't have a heat pump, nor does our thermostat have that setting. You may be right about our thermostat being on its last legs; hopefully it can limp thru this month-long trip. We greatly appreciate your idea of shutting off the breaker for the a/c and have just now followed your advice.☺️ We'll see how tonight goes.

Barb

[John Dorrer]

Barb, did you try the factory reset that Jason showed on his Thermostat video? I would give that a try before the breaker. The reset is to factory settings. Something might just have gotten out of wack. Worth a try.

Edited 21 hours ago by John Dorrer
Typo

[John Dorrer]

20 hours ago, jd1923 said:

Barb, do you have the Dometic thermostat set on furnace only, or on the heat pump setting. I don't think we have a heat pump, but there is the setting on the thermostat. When I accidently switch to that setting, no clicking, but the fan starts running above. There shouldn't be any signal sent to the A/C when in furnace mode.

If not, could be your thermostat is failing. I've got a possible work-around. Turn the 120VAC breaker off for the A/C. This may keep it from clicking, if it needs the 120VAC to make that noise.

That Domestic Thermostat has been a work horse. She has a 2021 LE2. There is a great video by Jason and he show how to reset the thermostat to factory default settings. Replacing the thermostat would be a last resort. I would try the reset before I did anything else.

 

There have been several owners that experienced this very issue and they solved the problem by doing a factory reset.

Edited 20 hours ago by John Dorrer
Updated Comment

[GlacierGirl]

@John Dorrer, yes, we did the reset ... still clicking!!!😵‍💫

[jd1923]

1 hour ago, GlacierGirl said:

@John Dorrer, yes, we did the reset ... still clicking!!!😵‍💫

Clicking when the breaker was off too?

Then it could be the Dometic control box vs. the thermostat, given the thermostat is operating the furnace and the clicking is coming from above where the control box is located. The only device in the A/C unit running on 12VDC.

@Ronbrink and @ChristianD, in the thread re updating the AC unit with a Tosot, had a discussion re the Dometic control box. Here's a link of what might be needed, if reset doesn't work. Nice kit for $120, contains both new thermostat and control box.

https://thervsurplus.com/products/dometic™-oem-3316230-700-9600024570-single-zone-ct-thermostat-w-control-board-cool-furnace-white?_pos=1&_sid=827d20bfd&_ss=r

Many of us are replacing the NOISY Dometic A/C and if you do that, all you need is one of these to run the thermostat. No clicking sound if the furnace has it's own thermostat!  🤣 

https://www.amazon.com/dp/B00H6ARNXO?ref=fed_asin_title

 

[John Dorrer]

2 hours ago, jd1923 said:

Clicking when the breaker was off too?

Then it could be the Dometic control box vs. the thermostat, given the thermostat is operating the furnace and the clicking is coming from above where the control box is located. The only device in the A/C unit running on 12VDC.

@Ronbrink and @ChristianD, in the thread re updating the AC unit with a Tosot, had a discussion re the Dometic control box. Here's a link of what might be needed, if reset doesn't work. Nice kit for $120, contains both new thermostat and control box.

https://thervsurplus.com/products/dometic™-oem-3316230-700-9600024570-single-zone-ct-thermostat-w-control-board-cool-furnace-white?_pos=1&_sid=827d20bfd&_ss=r

Many of us are replacing the NOISY Dometic A/C and if you do that, all you need is one of these to run the thermostat. No clicking sound if the furnace has it's own thermostat!  🤣 

https://www.amazon.com/dp/B00H6ARNXO?ref=fed_asin_title

 

Good Point👍

[GlacierGirl]

@jd1923, I've never even heard of a control box! I had no idea when we purchased this Oliver 1 1/2 years ago how much I would need to learn!!! Yes, I reset the thermostat and my husband shut off the breaker, and the clicking is as bad as ever. In a year and a half we have yet to use the air conditioner, so I don't even want to think about replacing it (even though it's volume was off the charts when we tested it). 

I'll go read the thread you mentioned. Thank you for sticking with me on this!

Barb

[SteveCr]

I had a similar clicking in the dometic control box. I eliminated it by changing the temperature differential setting on the dometic thermostat. There are instructions in the thermostat manual.  I'll try to attach a picture.

Steve