Forum Discussion

Sgeorge's avatar
Sgeorge
Explorer
Aug 01, 2016

Air Conditioner Not Shutting Off

Equipment both are Dometic brands, AC and Thermosat.

So the problem I'm having is the Thermostat is telling the AC to shut down at the proper temperature which the compressor does, but the fan never shuts down. I hear the compressor click off and the fan stay on. So the AC blows warm air continuously never shutting down. I don't know if it is a thermostat problem or the AC unit. Some background, the last time I used the AC it was running off of my Honda generator, the AC cycled off and then started back up as usual and my generator bit the dust. The generator went it to some type of overload problem and started running at a very high RPM and stopped putting out power. I never turned the AC on after this happened until just recently, I now have this issue.

Any thoughts
  • 2oldman's avatar
    2oldman
    Explorer II
    Aug 01, 2016
    The thermostat is the device that can control whether the fan is on constantly. Has that been ruled out?
  • BB_TX's avatar
    BB_TX
    Nomad
    Aug 01, 2016
    As 2oldman said the fan is selectable as "auto" and "run". Check to be sure it is set to "auto".
  • Sgeorge's avatar
    Sgeorge
    Explorer
    Aug 01, 2016
    The thermostat only has Furnace, Cool, Fan. We have always run the AC on Cool. No Auto feature.
  • 2oldman's avatar
    2oldman
    Explorer II
    Aug 01, 2016
    Sgeorge wrote:
    The thermostat only has Furnace, Cool, Fan. We have always run the AC on Cool. No Auto feature.
    And what about Fan?
  • fj12ryder's avatar
    fj12ryder
    Explorer III
    Aug 01, 2016
    If it's like our bedroom AC unit, the Fan setting is just Fan, no heating or cooling, just the breeze of the fan.
  • SkiingSixPack's avatar
    SkiingSixPack
    Explorer
    Aug 01, 2016
    When the AC compressor shuts off, the air that keeps blowing is air from inside your camper. It is not air from the outside, at least if everything is sealed up correctly. Now, I know that this does not help you with your question about how to run your model so that the fan does shut off, but I just thought I'd let you know that the ACs are designed to just recycle the inside air and they do not pull in outside air.

    We always run ours with the fan always on, and then control the temperature with the temp dial. Running the fan constantly helps keep the RV much cooler (air flow) and helps prevent the compressor from freezing up.
  • Sgeorge's avatar
    Sgeorge
    Explorer
    Aug 02, 2016
    Our Tstat doesn't have the sub menus as shown in the link. We do not have the option to control fan speed, Its either on or off. The AC unit dosn't have an option to control the speed.
    The unit functioned fine (shutting off/cycling) before the generator incident, now it won't turn the fan off.
  • Sgeorge's avatar
    Sgeorge
    Explorer
    Aug 02, 2016
    Ok, I fixed the issue. Dougrainer was correct my Tstat did have the sub menus. On the black unit I couldn't see the arrows with my old eyes. The fan speed had gotten set to high which had the fan run continuously. Now that it is on auto it runs correct. Thanks for the help, I learned something new about my trailer.
  • dougrainer's avatar
    dougrainer
    Nomad
    Aug 02, 2016
    Sgeorge wrote:
    Ok, I fixed the issue. Dougrainer was correct my Tstat did have the sub menus. On the black unit I couldn't see the arrows with my old eyes. The fan speed had gotten set to high which had the fan run continuously. Now that it is on auto it runs correct. Thanks for the help, I learned something new about my trailer.


    Also, IF you do NOT set to Auto, when you run the furnace the AC fan will run at whatever Fan speed you have it set at. Doug

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