Forum Discussion

lj2654's avatar
lj2654
Explorer
Aug 07, 2019

Dometic a/c

I am having an issue with a Dometic roof air unit. I use the genset to power my ac units when traveling.

The front ac sometimes cycles off, then comes right back on, runs a bit then goes off, back on again.

This happens on shore power too, same way, but not all the time...quite new roof unit and new thermostat. Air blows cold...

Where would I begin to figure it out?
  • you ac start capsiter and run side is bad replace it. you can find them cheep on e bay and easy to swap out .
  • time2roll wrote:
    Hondavalk wrote:
    Could be operating as it should. The blower shuts down as it changes fan speed
    +1 on the fan speed change. Mine does this and sometimes will go back and forth a few times in 10 minutes as it switches.


    You can test this by going into fan mode on the thermostat and taking it off of auto. You will be stuck with whatever speed you select until you change it back. This includes when the compressor is not running.
  • Hondavalk wrote:
    Could be operating as it should. The blower shuts down as it changes fan speed
    +1 on the fan speed change. Mine does this and sometimes will go back and forth a few times in 10 minutes as it switches.
  • thanks for all the advice. I will check it out more.....not a heat pump...
  • The compressor should shut off before the fan. The compressor will cycle on and off as temp. nears the set-point. If both the compressor and fan are cycling on and off, there is more than likely an interruption of power to the unit. Start by checking you supply breakers for the AC. Could be some loose wiring.
  • Could be operating as it should. The blower shuts down as it changes fan speed
  • If the AC has a remote thermostat pickup it may be poorly located and subject to heating for example when the sun moves, you put the awning out etc.

    I eventually bought a new pickup thermostat and just poke the little head of the device out the back side of the AC intake area. Seems to have really solved the cycling issues.

    That said, one of my AC's shorts cycles when the inside and outside temps are about two degrees apart. Moving the actual thermostat setting just a degree or two higher or lower solves that.