Forum Discussion

rvnwing's avatar
rvnwing
Explorer
Jul 29, 2013

Roof Air Conditioner on a 5th wheel leaks when it rains

I have a roof air condition on a 5th wheel that leaks ONLY when running the air when it is raining. Shut the air off when it is raining and the leak stops. Can operate the air when it is not raining with no leakage. This is the main air unit for the camper, not the add on unit in the bedroom


Weird problem, any suggestins ??

9 Replies

  • camperpaul wrote:
    Atom Ant wrote:
    Rain normally gets into the upper part and then drains back out through the weep holes in the pan on either side. That is also where your condensate drains out on the roof. It sounds like your fan is pulling in rain and its leaking through the pan somehow. I would take the cover off and start checking the pan and seals.

    Those weep holes frequently get clogged and the pan will overflow into the interior of the camper.

    It only takes a few days of camping near a cottonwood tree to clog the holes.

    You can clean them with a pipe cleaner (the kind with bristles).
    Ah yes, didn't even think of them getting clogged.
  • Atom Ant wrote:
    Rain normally gets into the upper part and then drains back out through the weep holes in the pan on either side. That is also where your condensate drains out on the roof. It sounds like your fan is pulling in rain and its leaking through the pan somehow. I would take the cover off and start checking the pan and seals.

    Those weep holes frequently get clogged and the pan will overflow into the interior of the camper.

    It only takes a few days of camping near a cottonwood tree to clog the holes.

    You can clean them with a pipe cleaner (the kind with bristles).
  • Rain normally gets into the upper part and then drains back out through the weep holes in the pan on either side. That is also where your condensate drains out on the roof. It sounds like your fan is pulling in rain and its leaking through the pan somehow. I would take the cover off and start checking the pan and seals.
  • RoyB's avatar
    RoyB
    Explorer II
    Here is a neat little pictorial diagram I found on the google search showing the roof seal gasket...

    Mine got so lose one time I almost lost the top unit...



    I think the rule is to depress the roof gasket just an 1/8-inch or so by tightening down long the four long bolts.... Probably vibrations and old age of the roof seals are the problem.

    I also get dripping from my air conditioner when it freezes over some. This usually happens in the middle of the night when it is very humid outside... I found keeping the blower speed on high keeps this from happening...

    Roy Ken
  • It makes perfectly good sense that it only leaks when operating in the rain because the vents or louvers are on the side of the unit. So you pretty much need to be sucking the rain in horizontally.

    What happens if you just turn a hose on it with unit off? If it leaks now without the unit running, then the roof seal is the most likely culprit.

    I assume the water is coming in where the vent/filters are located, often in the kitchen area.

    If there is not an obvious roof seal leak, I would just take the outer cover off take a look.

    If the plastic inside cover is cracked or deteriorated with age and heat from the sun, you should see something out of the ordinary.

    If the integrity of the inside cover has not been compromised, take that inside cover off as well, and see what you can see. If it is a seal it seems like you should see some pattern of water stains inside.

    Heat can be a real problem. The plastic squirrel cage blower wheel on my original Carrier A/C unit self destructed about year 4. No leaks, but lots of noise and plastic shrapnel. So anything is possible given how hot things get on the roof.
  • n7bsn wrote:
    it's not unusual for the hold-down bolts to be loose, or the gasket age out


    I agree. I recall four bolts which hold the unit down and pinch the seal to prevent leaks. I think it was a 9/16 socket that fit the bolts.

    I would remove the cover on the a/c inside your rig and make sure those bolts are snug. Mine were tightened fairly tight with just a 3/8 ratchet for leverage.
  • it's not unusual for the hold-down bolts to be loose, or the gasket age out
  • Could the vibration from the unit running or the air flow from the fan allowing water to comprise a weak roof seal? Air flow forcing water past the seal? Randu