Help - Roof AC shutting down intermittently

[ctcamper]

I think it is just off of warranty by a month so I will have to deal with this myself probably.
I was an electrician for a while but not much experience with AC units past recharging automobile AC.
It does this off of 30 amp supply or my 4k generator.
It will run fine for a while and then cause the breaker to trip or if I have it running on generator it will bog the generator down enough to cause it to shut down. It is the only thing running when the generator is running.

If I let it sit for a few minutes, it will start again and may go for another hour or it may go all day without a repeat.

Any clues on why or what may be the cause?

[J Walker]

I know a little bit about A/C. It surely sounds like you are drawing a lot of amps. I will speculate that the compressor is dragging the motor down. When it stops if you touch the motor is it real hot? On many A/C units the freon cools the compressor. If the freon level gets very low the compressor can overheat and fail. In your case it might mean that it is dragging the motor down. I would call Coleman, if they are the manufacturer, and see what they say. It isn't worth paying someone to fix since new units are not that expensive. You might get lucky and find a bad connection or a minor electrical circuit board you can replace. BTW even checking the freon level is tough on Coleman A/Cs because they don't have to my knowledge Schraeder valves to connect to.

[ctcamper]

It's a coleman mach 15k model 8335 - no schraeder valve in sight

531 bucks at ppl.

I thought I had a 13.5 as the documentation doesn't list the model lol

[TXiceman]

Youwob't find a Schrader valve on an RV A/C unless it has been a added.

First thing you need to do is to check the volts and amp at the compressor.

Ken

[RV Wizard]

Make certain that you do not have a vent pointing at a thermistor, as this can casue a unit to short cycle. If the unit tries to start artfer just cycling off the high head pressure can cause high amperage and trip breakers or bog down the generator. Check for loose connnections as this too can cause short cycling.

[wa8yxm]

That does not sound to me like a low-charge condition.. It sounds like a motor seizing up.. Since it happens on both Generator and shore power.. Well.. there is one thing I can think of that MIGHT be causing it which is easy to fix.

A bad connection:

I have found many RVers have a few screws loose.. No Not Mental screws, METAL screws (That one letter makes a big difference)

When I had A/C issues, (loosing power) I popped the cover on my breaker box and found nearly every screw therein needed a bit more torque,, up to 1 1/2 turns more torque in some cases (They were that loose) I tightened all of them black, white, green/bare,

Now... as I said, it might be a bad connection.. And since it costs next to nothing to tighten screws (Assuming you already have a screwdriver) I will suggest you check it out.

DO, remember to pull the plug (Unplug the rig) before you start.. Put the plug where you can see it please to insure nobody plugs it back in.


That said: I suspcet you need a new compressor. and replacing that, means replacing the entire unit

The warranty likely includes the phrase "You may have other rights which vary from state to state"

Those rights, MAY, include up to four years of "Extended warranty" protection (over the factory expressed warranty) IT pays to know the consumer protection law in your state.

Sometimes if is has been "Just a month"or less. they won't even give you a hard time about it.

[ctcamper]

I will check the uF value of the start and run caps as soon as I get a chance. Has been dark early and we have had a cold spell all of a sudden. I did try checking draw on the compressor last night even though it was only about 68 outside. It started at 8 amps and climbed to 11.18 in about 15 min, then the compressor cycled off. 15 minutes later it kicked on again and started pulling 11.30 and went up to 12.20 in about 10 minutes. I quit at that point and will wait for warmer temps, hopefully this weekend

[Bob (WA0MQE)]

There was a post awhile back about Coleman A/C's with respect to the motor seizing. The guy said he found the motor hard to turn. He replaced the motor which he listed the part # as 1468-3109 which you'd need to verify by the data plate on the motor. He also said it wasn't cheap. With shipping about $200. But cheaper then buying a new A/C as you stated, over $500. Said you could order it through Camping World, or other local service centers

Just a thought, I kept this information along with others, in my list of notes regarding repairs and fixes.

[ctcamper]

I haven't tested the capacitors yet.

The compressor starts at around 10 amps and continues to climb. Settles out at mid 15 amp around 15 minutes in and stays stable there for 15 - 20 minutes and then the amps rapidly climb till it trips the breaker.
I restarted it 10 minutes later and it kicked the breaker immediately so I ran the fan for 15 minutes and then it started, but then it climbed very rapidly and blew the breaker in a short time.

[ctcamper]

It is the compressor.
I am waiting on a call back from RVP and I hope they will replace it under warranty. I do have an old friend that I called who is an HVAC tech and said he would be glad to help me swap out the compressor. He has the evacuation pump etc..