Roof mounted Duo-Therm Air Conditioner and Heat pump
by Wayne Sager
Question: I have water dropping from the ceiling after turning on the air conditioner. This has never happened before.
Answer: The simplest source of the problem is high humidity inside your RV and outdoors. Since it seems that the air-conditioner only leaks when you turn it on, it is possible that you may have high humidity in your RV. What happens is that the cold surfaces of the air-conditioner are condensing moisture out of the air and it drips down onto whatever surface is below the air-conditioner. I had had that problem occasionally and was able to get rid of it by closing all the window and vents to allow the air-conditioner to do its work.
The most likely problem is a going to be up on the roof. If you are comfortable, working on your roof, remove the air conditioner shroud, the condenser coil cover, and the cover to the evaporator. Carefully inspect the condensation pan and whatever drain(s) it has for blockages or leaks. Another likely source is dirty evaporator coils. Since all the covers are off clean the coils. Use a good quality all-purpose cleaner like Fantastic or Formula 409 to clean the coils.
If your air conditioner discharges moisture onto the roof, a less likely problem could be that the bolts holding your air conditioner to the roof need to be re-tightened. If they were loose, you would also have leaks when it rained.
However, if you do want to go ahead and re-tighten them make sure you read your installation manual. It will tell you how much to tighten the bolts. The installation manual for my Duo-Therm calls for evenly tightening the bolts to 40-50 inch lbs. My manual covers model #’s (620515.321 and .421), (620525.321 and .421), (620526.321 and .326), (630515.321, .326, and .421), and (630516.321 and .326).
If your gasket is the problem, I suggest you have it replaced by a competent repair shop. My air conditioner weighs about 100 lbs and you would have to lift it to remove the old gasket and replace it with a new one. I will usually tackle most problems but this is not one of them.
Hope these suggestions will help you resolve your issue.