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kcolivier · 07-31-2011, 06:25 PM

I recently fount out my solution to the same problem, but I was connected to shore power. First, AC voltage measured 108, not the nominal 120 Volts. Second, I had the water heater on electric, not gas. Main breaker is 30 Amps. AC breaker is 20 Amps, while water heater is 15 amps. Add to that the low voltage and 100+ temp outside leads to a tripped main breaker.

Luv2go · 07-31-2011, 07:09 PM

Quote:

Originally Posted by mamaperez

It is almost like the ac never cycles off. The blower does, but the compressor keeps going and overheats. If I manually turn off the compressor while the fan is cycled off, it does fine. What can cause this?

The compressor should never run with the fan off. When this happened on our old coach the cause was a stuck relay on the control board in the A/C unit. You should be able to get the model number off your unit and contact an RV parts place to help you find a replacement control board.

wa8yxm · 08-01-2011, 08:02 AM

Actually Luv, that's not 100% true.. On heat pump units the compressor may indeed run for a SHORT (And I mean SHORT) time after the blower kicks out if it's on automatic fan.

There is a reason for this, I do know it, but don't wish to go into it at this time.

On a straight A/C however this is not (normally) the case.

Ham_Hog · 08-01-2011, 09:58 AM

Read all the comments about this yet no one has said to have a qualified tech (or yourself if you have the experience) measure the current the A/C is drawing, clamp on amp meters work very well for troubleshooting this kind of problem.
Bruce

Luv2go · 08-02-2011, 07:14 AM

Quote:

Originally Posted by wa8yxm

Actually Luv, that's not 100% true.. On heat pump units the compressor may indeed run for a SHORT (And I mean SHORT) time after the blower kicks out if it's on automatic fan.

Interesting. I do know that our Dometic heat pumps turn everything off at the same time. Have not listened to our new heat pump at the house, that may operate as you describe. You learn something every day.

wa8yxm · 08-02-2011, 09:12 AM

More likely to run on on a house unit.

One other thing I forgot to mention to the Original Poster.

CLEAN THE BEAST.. Go "up on the roof" (title of a song) and remove the covers and clean the evaporator and condenser coils, the fan and blower, and the water tray and anything else that looks like it can stand cleaning, IF the motor has lubrication ports... Lube (You may wish to download the owner's manual to see the lube specs) not all do (not many do) but if it has 'em use 'em.

This will reduce the load on the breaker if you have not already done it.