How to Fix RV air conditioner?
Roof Air Conditioner Water Leaks
A fairly common complaint is that of water leaks from the rooftop air conditioner. These do not have to be nearly as hard to find or fix as people often make them- they simply need to be dealt with in a systematic method.
The first question when dealing with this type of leak is- does it leak when it's raining or when the air conditioner is running (or, more rarely, both)? To deal with either, we need to look closely at how the air conditioner is mounted, and how it deals with the condensation generated while running.
The main thing to keep in mind, is that the air conditioner is sealed to the roof using a sponge rubber gasket- this gasket is compressable, and really is a long term maintenance item (they can last years, but not forever). This gasket is compressed by 3 or 4 bolts running from the inside assembly up to the top. For either "rain only" or "while A/C is running" leaks, first make certain there is at least 1/2 inch of gasket left (it is not tightened right down to the roof), then check the bolt for tightness- just make sure they are all snug, but don't over tighten- there must be the gap between the bottom of the A/C and the roof.
The reason for this gap is that on most roof top A/C/ units, the condensation drains out the bottom of the unit- between the base of the air conditioner and the roof. For this reason, never, ever seal around the perimeter of the air conditioner- I cannot say how many times I have had to deal with a unit where someone slopped goop around the base of the air conditioner, trapping water in where it has to leak inside. The "inside"coils of the air conditioner sit in a drain pan, to collect the condensation, which then runs out a small hole in the side, and out the bottom.