hello,i have a 28 foot toy hauler that has an onan generator from the factory. when i bought the trailer and the salesman was showing me how everything worked he used the generator to show me that the a/c unit worked fine with generator power. however the trailer has been sitting all winter and decidied to check the ac unit before the summer heat. i did this with no shore power just the generator. the fan blows fine and after the ac unit running 15 minutes the air was barely cold. any suggestions?

What is the ambient temperature?

Does the A/C work correctly on shore power? If yes, then it is a generator or switch problem. If no, then it is an A/C problem.I suspect an A/C problem.

Did you set the thermostat to the coldest setting?Did you hear the compressor kick on?How big is the generator?It is certainly easy to hear the compressor over just the fan. If you have access to shore-power, I would check out the air-conditioner there first to rule out problems with the unit. If the compressor does not start, check for a tripped circuit breaker.Now start up the generator and first check for 120v,ac, power. If the microwave will run you have 120v, ac, from the generator. No 120v,ac? check generator circuit breaker. Does your RV shore-power cord need to be plugged into generator outlet? My Fleetwood MH does. Made that mistake last spring, and took a while before I remembered that stupid mistake.

Ok, well I guess it's warm enough to feel any cold air. I think I'd have to figure out first if the compressor is running, not just the fan. Do you have a way to measure the unit's amp draw? Or notice if the generator seems to be working very hard?

a/c unit hardly working on generator power | Good Sam Community

14 Replies

mudrat025
Explorer
May 05, 2013
Not a whole lot of info on how to replace a rv unit capacitor on .net or youtui figured I would just replace the compressor capacitor.I'm just not sure about how much stored power is actuaaly in the capacitor
2oldman
Explorer II
May 05, 2013
mudrat025 wrote:
Great, any chance you can walk me through how to check motor and capacitor?
try youtube
mudrat025
Explorer
May 05, 2013
Great, any chance you can walk me through how to check motor and capacitor?
MNtundraRet
Navigator
May 05, 2013
If you cannot find a tripped circuit-breaker, the compressor motor, or starting capacitator, may be fried.

Running an air-conditioner under "brown-out" conditions (low voltage) is premature death.
mudrat025
Explorer
May 05, 2013
also from my first post i ran the fan without the ac and the air was the same. so i kept fan on auto and kicked on ac and no pump???
mudrat025
Explorer
May 05, 2013
ok went and hooked up and brought the hauler down to shore power. i have 125 volts with generator running, 114 volts hooked to shore power.there is a three way switch that is in the up position puts power to microwave. middle is nothing and down is a/c. the microwave works when i put it in the up position so i am thinking that switch is good.the ac pump is definetely not kicking in... any suggestions from here?
skipnchar
Explorer
May 04, 2013
Sounds like you need to have the AC serviced. Most likely is low on coolant and that means you'll nee3d to have a valve installed in order to add it. MANY RV air conditioners don't have the valve when manufactured. All of this assumes that the compressor is running (you didn't say it was or wasn't) but of course it it's NOT running it may be more serious.
ChooChooMan74
Explorer
May 04, 2013
How humid is it? IMO, they work best when it is humid out.
mudrat025
Explorer
May 04, 2013
i will check generator as trailer is sitting at vacant acerage. i will get back to you thanks
2oldman
Explorer II
May 04, 2013
Ok, well I guess it's warm enough to feel any cold air. I think I'd have to figure out first if the compressor is running, not just the fan. Do you have a way to measure the unit's amp draw? Or notice if the generator seems to be working very hard?

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a/c unit hardly working on generator power

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