Dometic Duo-Therm A/C Clicking - Will not turn on

[hdoug]

Hello,

I have a roof mounted A/C with wall mounted thermostat. It is a Dometic Duo-Therm unit. When I flip the thermostat to A/C, I can hear it click in the A/C but nothing happens. I can get the furnace to click on from the thermostat which leads me to believe it is something wrong with the A/C it self.

I have taken the cover off of the A/C unit and the fuse is good. Just when I flip the thermostat to A/C it clicks and nothing happens.

Anyone have any insight or familiar with these units?

[BFlinn181]

It could be the starting capacitor, a common part that fails in A/C units. Luckily it is replaceable by owner.

https://www.youtube.com/watch?v=oHgXGlYNYkQ

[hdoug]

Hi there,

I will definitely need to get one of those in the future. Is there a way to tell if that is the culprit compared to the actual relay board?

My A/C has been working fine every day. I ran the furnace for the first time yesterday as well as today. It got warm this afternoon and I went and flipped on the a/c and now all of a sudden it clicks. No warning signs or anything.

[CJ7365]

Just so you don't get confused the video is installing a Hard Start Capacitor, a lot of times you will install these if you have a small generator trying to run the A/C


There are at least 2 capacitors, one that runs the fan and one that starts the A/C compressor, usually when one of these fail, you can tell by looking at the capacitor itself, it will be bulged/burnt marks on top.


If these look good then could be your CB but more TS will be needed.


Check the capitors first as they as cheap usually $20-$30