Question about Dometic Rooftop RV Air Conditioner

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Dometic roof air compressor comes on but fan will not replaced both capacitors and thermostat

Control box is not clicking fan upstairs moves freely

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  • 282 Answers

Sounde as if there is an open winding in the fan motor. There are two sets of windings in a fan motor. The start winding and the run winding.

Here is how you can tell if it is the start winding. Put the unit on and then take a stick and try turning the fan swiftly. If it does start and it could be in either direction, since you have already replaced the capacitors then if the start winding is open then you will need to replace the fan motor. Same goes if the run winding is open.

Posted on May 11, 2014

  • gary jennings
    gary jennings May 11, 2014

    thank you very much, thats the closes anwser yet. I no its been awhile will try tomrrow morning. the unit coming down and will be replaced with a 15000 btu you see had to way options $135 for new digital stat and new shroud $180 and a new fan motor whatever that cost . ill keep the unit and replace each item over time and then add the unit to this camper as an extra a/c , it gets hot in texas but thanknyou for the information. 2009 outback 32 fifth wheel two slides

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Posted on Jan 02, 2017

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motor1258
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SOURCE: dometic air & analog thermostat control kit

Had one doing similar recently, and after a thunder & lightning storm. Nothing worked, but kept blowing 2 amp fuse in thermostat, when anything tried, heat or cool. Pulled plastic control box down from inside upper unit (AC) made sure breaker was off, took of plastic cover and smelled inside, and could smell burnt plastic smell. Replaced, control box, that got fan only working. Tried another thermostat , everything worked as it should. Turns out the lightning, or power surge, or whatever, shorted out the thermostat, and control box at same time.

Posted on Aug 14, 2008

Therinnaiguy
  • 1420 Answers

SOURCE: Have a 2009 34' Cougar 5th wheel with a roof

Sounds like a bad contactor. The contactor will be near the compressor on the roof.

Posted on Mar 12, 2011

  • 230 Answers

SOURCE: will not shut off

Sounds like a stuck relay on the unit itself. Maybe there is a short in the control wire that comes from the thermostat that activates the fan.

The thermostat probably has one hot wire at all times. The thermostat then chooses which wire to send the voltage down based on your selection. One of those wires is probably for the fan only. Make sure that it is in good condition (no bare, pinched or wires)

Posted on Jun 17, 2008

  • 230 Answers

SOURCE: dometic roof air

Sounds like the unit either has been miswired from the beginning or there is a stuck contactor relay.

The more rare scenario is that the control wire between the t-stat and the contactor is shorting to a power source causing the relay to energize. Good Luck!

Posted on Jun 23, 2008

jmeredith
  • 417 Answers

SOURCE: compressor tries to start but want

hi,
you have to run a contractor grade extension cord(10-12 gauge) from your rv to run those or theyll do that, the lower the gauge the better, best bet is to plug the rv directly into the outlet, if you cant, get the shortest and thickest extension cord you can.

Posted on Aug 21, 2008

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hi,
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