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pkhjr's avatar
pkhjr
Explorer
Aug 20, 2017

Brand new rv 13.5btu AC issue

I have a brand new Winnebago Micro Minnie with a 13.5 btu AC that runs fine but my 3400watt generator won't start it, goes to fault every time with nothing else going. I confirmed my gen to be good by starting a friends 15.0 AC with no problems. His RV was pulling 4 amps before we tried the AC so its not the generator.

So I climb up on my unit and check the start capacitor. The compressor side shows to be good. The fan side no capacitance. Ohm meter shows dead short. I'll replace the start cap but do you think that will solve the problem? It seems the fan side is so small compared to the compressor side.

Thanks Tex
  • ScottG's avatar
    ScottG
    Nomad
    Aug 20, 2017
    It's hard to check a cap with a DVM. The DVM charges it and you get odd readings.
    If you discharge the cap and then take an initial ohms reading, you should see the value keep changing.
    If the intial, discharged reading show a dead short, you've got your man!
    I wouldn't worry about the sizing of the components. They are sized to deliver the rated BTU.
  • 1320Fastback's avatar
    1320Fastback
    Explorer
    Aug 20, 2017
    Ive had it with our new Dometic AC. It consistently fails to run on twin Yamahas and even bogs down on shore power.

    Its getting thrown in the trash soon for a new Atwood, which Dometic now owns but hopefully they have kept their hands off it.
  • pkhjr's avatar
    pkhjr
    Explorer
    Aug 20, 2017
    I checked the start cap with a capacitance meter before I ohmed the fan side.
  • TomG2's avatar
    TomG2
    Explorer
    Aug 20, 2017
    pkhjr wrote:
    .... my 3400watt generator won't start it, goes to fault every time with nothing else going. .......


    I have to ask, what do you mean by "Goes to fault"? Like a gfci kicking out or a true overload condition? Just asking.

    Nine out of ten people that post similar posts come back and report everything it okay but they forgot about the converter, refrigerator, water heater, crock pot, etc. running the background.
  • pkhjr's avatar
    pkhjr
    Explorer
    Aug 20, 2017
    Guess fault is not the correct term. Gen goes to overload. I stated nothing else running. I threw the breakers for everything but the AC. I have determined the start cap is dead on the fan side. Just asking if that is enough to overload the gen. Regardless the start cap will be replaced.
  • dougrainer's avatar
    dougrainer
    Nomad
    Aug 20, 2017
    1. Does the AC work on shore power?
    2. Is your AC a RVP(Coleman) unit?
    3. IF it works on shore power but not from your Genset, then add a HARD START kit to the AC unit and your problem should go away. You can get the kit from RVP or your local AC supply. Doug
  • pkhjr's avatar
    pkhjr
    Explorer
    Aug 20, 2017
    Works fine on shore power. Unit is Dometic 13.5k btu. A new AC should not need hard start. I'll replace the current start cap and see what happens. My gen is more than enough to start the Dometic.
  • 1320Fastback's avatar
    1320Fastback
    Explorer
    Aug 20, 2017
    I broke out a old Onan BFA that I have for emergency power today. It is 33.3 Amps vs the 26 Amps that the twin Yamahas have and it ran my Dometic 13.5k with no issues.

    Atwood Ac here I come!

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