AC not starting

dewwood

Well-known member
We have a Duo Therm 15K on our Sundance and it seems to work well during the day when it is very hot, however mainly at night when the temps cool somewhat we have a problem. The unit will try to kick on and will hum for a few seconds and kick off then about two minutes later it will do the same thing, the fan will continue to run(set on auto) but the unit will not kick on and continue to run. It cools fine during 90 degree weather so the unit is working except when temps cools off a little and I am afraid the constant trying to start is hard on the unit. Normally on auto the fan will shut off when the unit does so the fact that the fan is running but the unit will not tells me it is trying to come on but for some reason it will not. Any ideas about what the problem may be?
Thanks,
Dewey
 

Rickhansen

Well-known member
Do not allow your A/C to continue to try and fail to start like this! You will burn up your compressor very quickly. There is a a thermal overload in the crankcase of the compressor that is shutting it off; once it cools down a little bit, it allows the compressor to try to re-start. The heat can build up internally and damage the compressor.
It sounds like you could have a weak start capacitor, which provides a little "extra juice" needed to start the compressor especially when it's cool outside. You also could have an overcharged condition which allows liquid refrigerant to get pulled into the compressor. Liquids do not generally compress! This can damage the compressor also.
 

Shadowchek

Well-known member
The most common problem would be a lack of power to the unit. If you are using an extension cord use a big one as short as possible. No less than 12 gauge should probably be 10 gauge if running other things like fridge water heater. If that isn't it you either have low voltage, a weak or bad run capacitor or a compressor that is hard to start. If you have a big enough extension cord or no extension cord the first thing I would do is check the voltage. If that was 110v A/c or more then I would check connections on cords and breakers. Then I would check the capacitor. A Compressor can run a long time with a weak capacitor but will run hot and be hard to start. Chances are it is a small or to long extension cord or bad connection somewhere along the line.

Greg
 

JohnL

Sundance Product Manager
Dewey, i will pass this info onto Jim Fenner, maybe he can get things going on your a/c - Thanks John Sundance Maganer
 

Princess Kathleen

Well-known member
We had a similar problem.....we replaced the thermostat and disconnect the overhead light fuse as per say Dave from Holmes on Wheels repair. Working better than ever.

pk
 

dewwood

Well-known member
Thanks PK,

I have an appointment with Dave from Holmes on Wheels on Mon. Hope it is just a simple fix. Will let the forum know the outcome.

Dewey
 

dewwood

Well-known member
Showed up at Dave's about 8:15 and he went right to work on unit. Decided we had air leakage in the unit leading into the duct work. It was allowing cold air to enter the area above the unit where the sensor is located so when outside temps were not that high it would get enough cold air to tell it to shut off then in a minute or two as soon as the sensor warmed up it would tell it to turn on. Dave put some foil tape in the duct area to seal the holes and it seems to be working ok now, time will be the test. Back on the road home by about 9:15 so not a bad morning. Heartland covered the warranty work(it was not very much) and we hope that fixes the problem.

Got almost home near Angola and met a Big Horn on US 20. All in all a good day. Thanks to Dave and to Heartland!
 
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