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StephenandRobbi's avatar
StephenandRobbi
Explorer
Jun 03, 2013

AC fan will not start

I have a Duo Therm AC model 57912. When the unit is turned on the fan will not start. It will run if you give it a turn by hand. I replaced the start capacitor and it did not help. I don't see any reason to suspect the run capacitor so I'm leaning towards replacing the motor. Any thoughts?

Thanks,
Steve

10 Replies

  • StephenandRobbi's avatar
    StephenandRobbi
    Explorer
    Jun 09, 2013
    Ok, everyone who voted for the run capacitor, you are correct. I replaced it today and the AC seems to run fine. Thanks again for all the help.

    Steve
  • Chris_Bryant's avatar
    Chris_Bryant
    Explorer II
    Jun 04, 2013
    Just replace the run capacitor and it will be fine. FWIW, I have only found a motor with electrical problems once , and that was due to being hooked up incorrectly. Every other motor I have ever replaced has been due to bad bearings (and I have replaced a bunch).
  • Ex-Tech's avatar
    Ex-Tech
    Explorer
    Jun 04, 2013
    prolandsurveyor wrote:
    Are u talking about the blower motor? The motor that blows air inside the camper? Or the condenser fan motor that blows air on the top of your camper?

    On a RV air conditioner, the same dual shaft motor operates both the evaporator and condenser fan.
  • prolandsurveyor's avatar
    prolandsurveyor
    Explorer
    Jun 04, 2013
    Are u talking about the blower motor? The motor that blows air inside the camper? Or the condenser fan motor that blows air on the top of your camper?
  • StephenandRobbi's avatar
    StephenandRobbi
    Explorer
    Jun 03, 2013
    Thanks for the info.
    There are only 2 capacitors in the system. A run and a start. Since it would run once started I assumed the run capacitor was good. It will run in either direction though. So I guess the best rout is to replace the run capacitor and then the motor?

    Steve
  • PaulJ2's avatar
    PaulJ2
    Explorer
    Jun 03, 2013
    Chris Bryant wrote:
    The start capacitor has nothing to do with the fan. If it spins freely, replace the fan capacitor. (You can double check and try spinning it backwards- if it runs backwards, the fan capacitor is definitely bad)


    X2 on this.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Jun 03, 2013
    Every last one I have ever torn down with those symptoms had a burned coil or two in the stator. Time to grit your teeth. Low voltage is a usual suspect.
  • Chris_Bryant's avatar
    Chris_Bryant
    Explorer II
    Jun 03, 2013
    The start capacitor has nothing to do with the fan. If it spins freely, replace the fan capacitor. (You can double check and try spinning it backwards- if it runs backwards, the fan capacitor is definitely bad)
  • pianotuna's avatar
    pianotuna
    Nomad III
    Jun 03, 2013
    Hi,

    If there is a setting for running the fan constantly use it.

    Some folks have tried to oil the (probably sealed) bearings.

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