Diometic Air Conditioner

[Straylee]

One of my 2 Diometic Air Conditioners quit cooling. Fan still runs, compressor does not. I am capable of removing the vent cover and AC cover. Is there something I can do from there or should I have an expert take over?

[sundancer 87]

Originally Posted by Straylee

One of my 2 Diometic Air Conditioners quit cooling. Fan still runs, compressor does not. I am capable of removing the vent cover and AC cover. Is there something I can do from there or should I have an expert take over?

It would be very helpful if we knew what RV you have.

Can't offer assistance without this information.

[Straylee]

Oddly, the AC started working again. We had it on for 3 cycles since and it works. However I'd still like to know what the cause/cure was.

[sundancer 87]

Could be something as simple as a loose connection on the start capacitor but it's hard to diagnose when it's working.

[fgargiulo@comcast.net]

Without details its hard to say. My wild guess is possibly the quality of your shore power. Sounds to be running 2 ACs plus everything else requires good amps. If the circuit is 30 amps of less it might not be enough to run everything at once. Hence the now it works,

Just my guess.

[leisuresolar@gmail.com]

Recently my bedroom air quit working. After a bit of troubleshooting, I determined the switch that was mounted on the AC unit was bad, not delivering voltage to the compressor. A new switch was hard to find, but I finally did at $27 and it fixed the problem.

My main troubleshooting steps were:
1) Inspect the AC unit on the roof, to see if I could find leaking freon. Turns out this was a wasted step because low freon in this particular AC unit does NOT cause the compressor to NOT turn on.
2) Turn off the AC main breaker and the inverter to remove all power! Take the AC cover off in the bedroom. Remove the cover to the switch. Ohm out the switch. It actually ohm'd good. Re-apply power and trace the voltage signal (I'm an electrical engineer, don't do this if you don't understand 120V circuits.) The voltage was not appearing on the compressor terminal, hence the switch was not passing it, even though it ohm'd OK.
3) Build a bypass cable and jumper the AC around the switch. Wahlah! The compressor came on a got cold. Hence the switch was bad.

This is a bedroom Dometic that has the thermostat and switch actually mounted on the AC unit. If your AC unit has a wall thermostat, this answer doesn't apply.

By the way, I took the old switch apart for fun, and found the problem and fixed it. SO now I have a spare switch!

[sundancer 87]

1) Inspect the AC unit on the roof, to see if I could find leaking freon. Turns out this was a wasted step because low freon in this particular AC unit does NOT cause the compressor to NOT turn on.


You won't find the tell tell oily deposit around a leak in refrigeration units these days, not since R12.
The new refrigerants don't have Capella oil in them so no dirty signs will show up. Not even the old sniffers will find a leak.
It's a different game in the refrigeration world now. Your old R22 equipment will be phased out and the R40 is on its way also.
When the 5 year old A/C needs refrigerant be ready for total replacement because these gasses won't be available.


When R12 was outlawed in the good ole US there was, at one time, more R12 crossing the borders than drugs.