AC when on generator

[jcgso]

Today I went to the storage lot to do some work on my Dutchman Dorado 26BE. It was very hot and humid, so I started the generator (Onan 5000), thinking I could get the overhead AC to work. Only the fan came on. Is this normal, or was there something I should have done? We have had it for less than a month and it’s our first class C, so still learning. I am planning on doing some boondocking this summer, so want to have AC if needed.

[LJowdy]

First thing is to make sure the A/C is actually in the on/Cool position. Many A/C units have 'fan only' If that's confirmed then you probably have a bad A/C

[irishguy]

How long did you run the a/c before you figured only the fan would come on?

RV a/c's often have a lengthy delay before the compressor kicks in.

[Arch Hoagland]

My air conditioner fans will run about three to five minutes before the compressor kicks in. Both on campground power and generator.

[Spdracr39]

I have noticed that the delay on mine is longer if it happens to lose power while the compressor is running then you turn the unit back on. As stated above it can be as long as 5 minutes. On my Dometic thermostat there is an hourglass that shows while it is waiting on the compressor to come on.

[twinboat]

When I first start my generator, the automatic transfer switch, 30 second delay runs down, and then the AC comes right on. Both fan and compressor, cooling the RV.

If I was to turn it OFF and quickly back ON, then the delay in the AC system starts, allowing the compressor pressures to equilize. That can be up to 10 minutes, never timed it.

[jcgso]

LJowdy, I did make sure it was in the cool position. I tried switching back and forth to see if that would help. Thanks for all the replies. It sounds like I may have a problem.

[Sbrownstein]

Switching back and forth between off and cool will probably actually cause an additional delay. A/C compressors do not start well if there is system pressure from a previous run. Many thermostats enforce a 3 to 5 minute delay as a "compressor protector." Undoubtedly the flashing hourglass is indicating that the thermostat thinks the compressor has just run and is waiting for the head pressure to drop before restarting.

Leave the thermostat in the cool position and put the fan in the "auto" mode. If after 5 minutes or so you the compressor fails to start, you may have a real problem with the compressor or capacitor or somewhere else in the system.

[sgpd1sam]

I have a similar problem in my 2008 Four Winds. It sometimes takes a while to kick in but in my case it is the transfer switch. I guess it transfers power somehow to run appliances and such when the generator is running. I’m not savvy enough to really know.
Sounds like a complicated replacement for a layman though. I gather all the electrical runs through it and can really muck things up If you wire something wrong.

[henzlgc]

Be sure the circuit breaker on the generator has not tripped

[Stevegd007]

Originally Posted by henzlgc

Be sure the circuit breaker on the generator has not tripped

Yep! When your Genny is running an you have no 110v power to the RV is usually the breaker directly on the Genny. Check that.

[jcgso]

Hoping to get to it tomorrow. I will check the breaker.

[Mudfrog]

Originally Posted by henzlgc

Be sure the circuit breaker on the generator has not tripped

The circuit breaker is fine since the fan runs.

OP, crank the genset and make sure you have 120 volts inside the rig. Then put thermostat in cooling mode, set the temperature below the current inside temp, and put the fan in auto. There may be a short delay so give it a few minutes before touching anything else. If only the fan ends up running, then some troubleshooting will need to be done. Could be something as simple as a broken/loose T-stat wire or bad T-stat itself.

[hermoneypit]

A/c works on shore power. The a/c has worked on generator since i've owned its a 2018 four winds only one a/c. No fan, Nothing on a/c. HELP