Question about Dometic Rooftop RV Air Conditioner

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Duo-Therm Sunchaser XL

Have the above rooftop ac. RUns great for about 3 mins then slowly bogs down and finally shuts down. The blower will come back on shortly after the compressor shuts down. It will then try to restart after a few minutes but fails.

I am going to take a guess and say this might be due to lack of voltage from the main breaker we are getting power from. Reason I say this is that even the smaller fans we use in the 5th wheel slow down when the ac is trying to start.

We are on a 30 am breaker with about 70' of underground 10 guage wire from the breaker box to the trailer.

I am going to going to guess that if I shorten the run and run 8 or 6 guage wire I would eliminate my issue.

I may have answered my own question but confirmation would be great from some experts.

Thanks in advanced

Posted by on

  • kamper2 Aug 09, 2008

    I also have the problem with our a/c running fine for a while then the compressor stops (with a shudder) but blower continues to run as if it just kicked into hight gear. After a few seconds the fan also stops - then a few minutes later it cycles on again.
    1) We do not have any problems with the voltage whatsoever - I feel it is something else.
    2) Dometic repairman said it is not a problem with the temp sensor.

    What is it then?

  • Ron Henry III
    Ron Henry III May 26, 2017

    Kinda of late for the OP but still relevant to ALL AC systems.

    If the external blower motor is failing and not providing proper airflow to the condenser, the Freon will "ice" up and overload the compressor which stalls, overheats and trips the thermal breaker. This will leave the internal blower running until such time the thermal breaker rests and the process starts over.

    IF the external fan and internal blower share a common motor, the failure will be more noticeable as the blower starts failing.



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Do you have the right voltage going to the RTU .You should double check voltage and amp draw on compressor.
Breaker and wire should be fine .Also make sure everything is wire according to the correct phase

Posted on May 26, 2017

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Your wire size and breaker is correct and should be fine as long as all connections are tight and plug and receptacles are OK. Does any part of the wire get warm? Check the temperature of the plug (plugs/sockets) and cable at each end.

Posted on Aug 07, 2008


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