Help please.  I bought a '97 Trailite camper last year.  At the end of the season I tried turning on the A/C while the camper was just plugged into a wall outlet out of my basement.  I've done this in the past and sometimes it would trip the breaker and sometimes not.  This last time though, the A/C would not come on.  I adjusted the thermostat and could hear a humming, like it wanted to kick on but could not.  The fan in the “on” position works.  I have a feeling I have caused a problem by plugging the camper into an outlet not rated for pull of the A/C.  Anyway, I took it camping and at a 30 amp site, it did exactly the same thing. 

My thoughts were to service what  I could, clean the filters and such.  I was reading about one of the “mods” of the “hard start capacitors”.  Could this be this issue and by installing or replacing the capicitor fix the issue?  Thanks so much for any input. 

-Woody

Take the cover off, spin the fan blades by hand, then have someone start it up after your hands are clear. Most will have a start capacitor on them, most of the newer ones.

Motors get a 'dead spot' sometimes when sitting. I am a HVAC business owner and operator so I have been there on this. Hope that is all it is. The humming you hear is probably the compressor, I bet the fan is stuck. The fan runs the inside evaporator airflow as well as the outdoor condensing airflow on these small units. One motor, 2 shafts and 2 fan blades, or squirrel cage.

Robert is on the mark about low voltage, he is giving good information.

Usually if you have a low voltage it will increase amp draw and blow the 15 or 20 amp house circuit. A 12 gage extension cord will be good if you are within 35 feet or so to run it for a while, this is assuming you are plugging into a 20 amp circuit with 12 ga. wire feeding it. Lots of variables.

Try the spin deal. I always recommend when storing a trailer, try to run the fans on the A/C unit once every few month's for 3 or 4 minutes, the compressor isn't that critical, since it is all enclosed and sealed up. Good luck.

It is possible, while you have the top off spinning the shaft, if it does not start after freeing up the motor, you can change the cap. it will have a value on it, 45-5 or something close. I have changed out over a hundred of them this summer. There will be a C. terminal, common, a F. for fan and H. for compressor, (hermetic) 

Just buy the same value and change wire for wire, be careful, they can shock you, short the terminals with a screwdriver before you unplug the wires. If they have a resistor across the terminals, it is a 'bleed resister' and it leaks off.  And, make sure the breaker is off to the unit when you work on it…

You can get them at a local Johnstone Supply Co. and many other places on the Internet.