'81 FC 35' ac trouble

[Katsrv]

One of my rooftop dometic AC units will not stay running. When I'm on generator power and I turn on the AC unit, I hear the motor bog a little bit for about 15 seconds and I can feel the cold air coming out of the vents .... but then I hear the pitch change on the generator back to high gear and it runs, just normal air, maybe even warm/hot air for about 30-45 seconds and then you hear the engine bog down and then the cold air starts coming out for about 15 seconds and it cycles like this off and on off and on ....what could be the issue?

[GEEZER]

Check all your wire connections and capacitors

[Bill Pape]

Originally Posted by GEEZER

Check all your wire connections and capacitors

And fans

[Orvie6574]

Install a hard start kit on it

[Katsrv]

When I did a bypass of the Klixon, it ran with cold air until I cut it off, no cycling.

[CrashTestDummy]

Originally Posted by GEEZER

Check all your wire connections and capacitors

Usually, if a start capacitator is dead, they won't start at all. A quick and dirty way to 'test' a capacitor is to pull it and set it on a flat surface. The bottom of the 'can' should be perfectly flat. If it rocks at all, you need to replace it. They're not that expensive, well, at least capacitators for home units aren't, and aren't that hard to install. Finding one can be unless you have a friend in the A/C business. I ordered a spare for my home unit, since no one had one in stock at the local hardware stores.



I'd be looking at the compressor, though, if it does start, but takes a lot of amps to start it spinning. You'll want to put a load tester on it and see how many amps it is drawing on start. Compare the same on one of your other units.


I hard start kit may help, but you'll probably end up replacing a compressor down the road. A hard start kit is a good thing to have, since it reduces the initial load and power draw on electrical system when the compressor starts.


You'll want something like this:
Digital Clamp Meter AC Auto, 600A:

https://www.acmetools.com/shop/tools...klein%20tools#

That's just an example, though.