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Ron_Nielson's avatar
Ron_Nielson
Explorer
Jun 04, 2019

Generic A/C Question - Limited Cooling Cycle Time

My a/c unit will start, run for a couple of minutes, then shut off. Will not stay on nearly long enough to get down to the thermostat set point. After that cycle, if I turn off the breaker for the a/c, and then try a couple of settings on the thermostat, it will start again, run a couple of minutes, shut off, rinse repeat. I forgot exactly which unit my 2009 Arctic Fox 29-5T is installed on my trailer, likely a 13.5 unit, guessing Dometic. Never any trouble like this since new in 2010, until now that is.

Given the very limited information I'm giving you (it's all I know at this point), what is your best guess at why the unit doesn't run longer??
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Jun 04, 2019
    Does fan continue to run....jus compressor shuts down?

    Does fan run if you place it on High or Low (thermostat setting)?

    Does it blow cool air?



    *Run capacitor
    *No freon...leaked out
  • Ron_Nielson's avatar
    Ron_Nielson
    Explorer
    Jun 04, 2019
    Old Biscuit - Glad to see you are still around. Your posts have helped me a lot

    The a/c unit, when running, appears to run as a normal unit. Fan runs on high until the entire unit shuts off, fan and compressor at the same time. You can run the fan separately without cooling if you wish. Unit seems to col just fine, just doesn't stay running long enough to cool the trailer. I have a separate hi/low fan switch, not a part of the thermostat and that functions as it always has.
  • DFord's avatar
    DFord
    Explorer
    Jun 04, 2019
    Until you said everything shuts down I was thinking the freeze protection may have been the problem but if it opens the circuit the fan should continue to run warming up the coils.

    Find the wiring diagram and see what controls would cause the problem you're experiencing.
  • dougrainer's avatar
    dougrainer
    Nomad
    Jun 04, 2019
    It would have helped if you had posted the PREVIOUS electrical problems you had with the unit just prior to this problem. Your Electrical burn out probably caused the problem with this AC unit. Until you give us more info on what brand/model and type Controls, we cannot pin point your problem. Doug
  • time2roll's avatar
    time2roll
    Nomad
    Jun 04, 2019
    Get a reading on the amp draw and compare to spec to see if the compressor is about done.
    Otherwise I would be looking at getting a new thermostat (as my best guess)
  • Ron_Nielson's avatar
    Ron_Nielson
    Explorer
    Jun 04, 2019
    I found the problem. The problem was with the thermostat, specifically the operator of the thermostat, in other words, 'ME'. It's a 7 day cycle set and I found the setting so that either the refer switch is COOL or OFF without regard to the actual day, and it does cool down to the set temp.
  • sbell2003's avatar
    sbell2003
    Explorer
    Jun 06, 2019
    I had this issue with my previous trailer and it was caused by the location of the thermostat. I mounted a cover over the thermostat with a cut out in the bottom. Solved the problem and the AC cycled normal.

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