Question about Dometic Rooftop RV Air Conditioner

1 Answer

I have a Duo Therm RV air conditioner probably put in when RV was made in about 1989. Started leaking through the ceiling last year down onto my floor, so I kept it off for a while. I would only try it now and then, but when I switched on the ac the fan intermittently would not come on at all. Eventually it quit altogether. However, just now I turned on the fan and ac to check it out. The fan is now working very well at all speeds...I don't know how long it will though...? It is a bit cool right now outside, so I won't be able to see if the compressor comes on, but I want to ask what I need to do to check out the problem of it leaking when compressor is on and why the fan doesn't come on at times even though I can hear the motor. Hope you can help. I will sure be needing the ac here where I live. Appreciate your thoughts and suggestions for troubleshooting. Thank you.

Posted by on

  • conjeaniel Feb 28, 2009

    Thanks, Farfield, for your response to my question. I turned my ac on the other day when it got to be 91 degrees inside the RV and it worked properly all day and without leaks. Fan...compressor...everthing worked fine. Thanks for the reminder about looking for oil hole. I'd forgotten about that. And I will check out the fins and and coils. I checked the outside, but not the inside, so I'll do that too.

    Very helpful!

  • conjeaniel Mar 02, 2009

    Farfield, I did write a rating. I'm sorry it did not go through. I gave you the blue 4 for excellent suggestions. Maybe you received my last post to you also, but then I don't see it here either so that might not have gone through. Might want the site tech to check out why neither of these were sent.

    My ac is working top notch now.

    Thanks for you excellent suggestions.



1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert who has written 7 tips or uploaded 3 video tips

  • Master
  • 462 Answers

I need more information. And if you have worked on AC's before? Thes main things to check I believ is the fan motor I just wrote out a long explanation as to what to check and look for and I think it got lost. SO I believe your hearign the compressor continue to run even when the fan stops. 
Eventually the compressor over heats and stops. this is when nothig runs. Here is where I believe te indoor coil has been covered with Ice-frost and when the compressor stops the ICE FROST melts and you get water on your floor. 
The motor could be bad or the run capicator  I also believe your indoor coil (and most likely the outdoor one too) is plugged up or dirty. A dirty outdoor coil is the most often cause of motor over heating and or capicator failure. If you can look through the fins of the outdoor and indoor coil ALL OVER then they are clean. Any area stopped up over 20% and you need to wash them out.
Take your capicator out and have it checke by someone with a capicator checker. They will most likely have a replacement if needed. Check the "STIFFNESS" of the motor bearings. If you spin it and it turns over 2 or 3 times or more the bearings are probably ok.  If it has oil holes add about 20 to 40 drops lite machine oil to the bearings. If they are sealed... Start looking for a repairman or take care if your goin to change it yourself. Too many factors to go into here about changing a motor. And some may or maynot apply.
Hope this helps you if I need to more clear get back to me and well discuss it more. GOOD LUCK!

Posted on Feb 28, 2009

  • Farley Redfield
    Farley Redfield Mar 02, 2009

    I'd like to be able to ask this person to please rate my response to their problem and grade me accordingly. Otherwise I feel like I'm wasting my time. Thanks for getting back to me.

  • Farley Redfield
    Farley Redfield Mar 03, 2009

    OK ty for your rsvp to my request. AND GOOD LUCK.



1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

How do you bypass a duo therm thermostat, which two wires would you touch together

That would depend on what you want to run, and wire colours coming from ceiling control box to thermostat. Need more info.

Nov 11, 2013 | Dometic Rooftop RV Air Conditioner

1 Answer

RV AC is working fine, but the water is leaking from the ceiling Where is the drain tube on the unit, The AC unit is a roof type, Duo Therm serial # 43404934, Part # 3105459

Normally, the condensate will drain out of the unit onto the roof and off the edge to the ground. Remove your cover inside (probably 2 screws) and tighten the 4 bolts you will find inside. If they are tight, go to your RV supply place and get new roof gasket. Remove the AC and insert the new gasket and resecure the AC to your roof.

Thanks for your question @

Jul 26, 2011 | Dometic Rooftop RV Air Conditioner

1 Answer

The Duo-Therm AC in the motorhome has started leaking from the inside after approx. 1/2 hour of use. What could be the problem?

More than likely water is pooling on top of the rv and leaking thru a crack next to the unit. The other problem would be the drain hole is plugged you will have to remove the top to ck. good luck

Aug 10, 2010 | Dometic Rooftop RV Air Conditioner

1 Answer


you could contact the manufacturer of the rv and they can help you with you search. Hope this helps


Jul 16, 2009 | Dometic Rooftop RV Air Conditioner

1 Answer

I have a duo therm brisk air model 57915-001 leak

Could be the drain path is clogged.. Take the cover off & see if you can get it cleaned..

Jul 09, 2009 | Dometic Rooftop RV Air Conditioner

1 Answer

Rooftop a/c not cooling as well as it used to.

How old is this unit? In the Duo-Therm Brisk Air Models, they were notorious for a small leak in the capillary tube that runs into the evaporator part of the AC. There are two small tubes that are run together, take the top off of the evaporator coil and pull the lines apart gently. Look for noticeable signs of leaking in the area. If the lines have been looking or look like they have rubbed together for an extended period of time, you need to have someone replace the lines or buy a new air conditioner. I would price both before committing to either one. Hope this helps.

Jun 29, 2009 | Dometic Rooftop RV Air Conditioner

1 Answer

Does anyone know if a Duo Therm model 620515.331c is ducted or not???

The upper unit itself is not ducted. They are all the same. The ducting is done with the lower unit or "Ceiling Pack" of the air conditioner. You need to see your RV is ducted, ie...vents in the ceiling that blow the are out. Usually they are round and mount into the ceiling. Another way to tell is if the unit has a wall mounted thermostat.

Hope this helps,


Jun 24, 2009 | Dometic Rooftop RV Air Conditioner

4 Answers

Duo therm air conditioner

my duo therm air works beautifuly all day but at night when we go to bed it seams to turn on and shut off rapidly. what could be wrong?

Jul 06, 2008 | Dometic Rooftop RV Air Conditioner

Not finding what you are looking for?
Dometic Rooftop RV Air Conditioner Logo

519 people viewed this question

Ask a Question

Usually answered in minutes!

Top Dometic Heating & Cooling Experts

Bill Long

Level 3 Expert

588 Answers

mike cooper

Level 3 Expert

884 Answers

Tim Whalen

Level 3 Expert

3074 Answers

Are you a Dometic Heating and Cooling Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides