Condensation building under luan ceiling

Discussion in 'Heating / Cooling Systems' started by G8tor38, Jun 29, 2019.

  1. G8tor38

    G8tor38 Member

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    2005 Fleetwood Niagara, Coleman 13,500 Mach A/C, just fixed a/c today after figuring out it was a bad “hard start capacitor”. Now I am back to our original problem of a leak above the luan ceiling panels that is warping the ceiling.
    The last time this happened was two weeks ago and we didn’t notice the air conditioner had been leaking until we opened the camper after arriving at the campground and noticed the stains on the canvas’s. This could have only happened as a result of running the a/c before we closed it up prior to leaving on our trip and condensation getting trapped between the luan ceiling and the roof, then running out after we closed it up to leave.
    Long story short, I called a repair man to find to leak, then called insurance to alert them to the damage. The repair tech notice that the duct between the inner and outer a/c unit was not re-installed properly and was probably causing condensation which was dripping in the ceiling, funny thing is though, everything on, in, or around the a/c seemed dry as a bone except the board running down the center of the camper under the roof. None the less, he fixed the duct and it seemed to fix the issue but I wasn’t convinced so we limited the use of the a/c for the remainder of the trip and ran it on low cool and as low a temp setting as we could to be comfy to reduce the possibility of building condensation. When we arrived back home I opened the camper back up to put in a dehumidifier and noticed some more staining on the interior a/c vent but figured it was some residual moisture that was trapped in the ceiling somehow that escaped on the trip home (Georgia Roads) so didn’t pay it much mind.
    Now back too today, I got the a/c working again, been running it all afternoon and took the wife in to show her how cool it was around 9:30 tonight. Even though I had it on low cool and the temp turned down it was still ice cold in the camper. I reached up to check the ceiling out of habit to see if there was any moisture that came out of the area of the seam that we had an issue in before and to my surprise, there was, again, the luan was soaked.
    Can anyone give me some thoughts on where they think this moisture may becoming from? It is not coming from outside the camper, somehow, somewhere it is coming off the a/c.

    Please help guys! and if anyone has pictures are a schematic of the roof on these models I would love to see it since I-will be rebuilding this one, it is a shame too, this was an almost perfect camper and if the guys who put the new a/c seal on last summer we’re worth anything, I don’t think we would be here discussing this.
     
    HappyTraveler likes this.
  2. GreyFox

    GreyFox Well-Known Member

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    I had a similar issue with the Carrier AirV I had installed on our 2000 Santa Fe. It only happened when the outside weather was particularly hot & humid - I solved it completely by lining the cold air duct with Reflectix.

    [​IMG]

    [​IMG]
     
    HappyTraveler likes this.
  3. rabird

    rabird Howdy!

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  4. WrkrBee

    WrkrBee Well-Known Member

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    Is condensate running off the top of your camper? If not, it could be a clogged drain. Looks like rabird has the same idea.
     
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  5. G8tor38

    G8tor38 Member

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    Thanks guys, Grey, the issue we have is above the ceiling line but we did find the duct was not in correctly and thought that may have been the issue so fixed that, but not it.
    Rabird/Wrkr, I’ve check the drains repeatedly, and they seem fine, I’m going back up this evening for another look. This only happens when the unit is running so that would make since but as far as I know there are only two drains on the Mach 13,500, one on each side that drain onto the roof, or is there more? I’m going to look at the link Rabird sent now and see what I can find, will report back tonight.
     
  6. rabird

    rabird Howdy!

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    There is a seal under the roof top unit to prevent water on the roof coming in, that should be snug and not over tightened from below.
     
  7. G8tor38

    G8tor38 Member

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    Thanks Rabird, we’ve had about 7-10 inches of rain a week about 3 weeks ago for a month lol, and the a/c had a new seal at the end of the summer last season. One of my concerns was opening the camper to a mess after the heavy rains but there was not one drop inside the camp, at least not from rain, it is all coming from the a/c which is so frustrating.
     
  8. G8tor38

    G8tor38 Member

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    Well, I closed the camper up and pulled the a/c apart to get to the drain pan, it was clean, a little bit of debris but nothing of concern. Since I had it apart I took the time to scrub the roof around the seal and remove some algae build up and clean the coils since the cover was off, and even with the hose end sprayer on the roof there was no water in the camper when I opened it back up, so we know the seal.
    The good side of all of this is the coils are clean, the seal is good, the pan is clean, and I have a new hard start capacitor on the a/c, and I finally got to scrub the algae around the bottom of the a/c.
    I did a thorough inspection while I was up there, I looked for cracks or rust holes in the a/c pan, but nothing, everything looks like the unit isn’t that old and we’ve only owned the camper a couple years and bout it used (2005 model). Any way of knowing how old the a/c is? The only odd thing I did notice was that they did not get the unit exactly square on the gasket when they replaced it last year, but it does work as it is. I’m hoping that maybe something like some insulation was hanging down off the side panel laying in the tray blocking the drain enough to back it up, but also letting enough wick by to make it look like it was draining properly. I had told my wife that in 97 degree weather we should see a lot more water coming off that roof.
    Hopefully something I did will make a difference, if not I’m pulling the unit next and bench testing it.
    Stay tuned.
     
  9. WrkrBee

    WrkrBee Well-Known Member

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    This depends on where you are camping in 97 degrees. In the southwest, there is very little condensate. Las Vegas has 15 percent humidity this morning. In the southeast, it pours. This morning we have 88 percent humidity already.
     
  10. WrkrBee

    WrkrBee Well-Known Member

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    I meant to ask you if the roof AC hole edge was sealed, assuming you have a typical foam sandwich construction. If water condensates on that edge, it can easily run under the luan.
     
    Sjm9911 likes this.
  11. G8tor38

    G8tor38 Member

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    Understood, i’m in central Florida but trying to get the camper to a point we can go to NC camping.
    Not sure I understand the question on the a/c hole Wrkr, but I have an aluminum roof with decorative masonite ceiling panels, and trust me, when masonite gets wet it stains everything. You would think the engineers at Coleman would have designed a way for the a/c to drain so it’s not so easily clogged.
    After I took the unit apart it seems I may have fixed the issue, the unit is peeing like a race horse as it always use too, prior to this it was only dripping, and like you said, with 90% humidity in Florida you should see an a/c pouring water out of it.
    I have run the a/c all night and water is all over the drive, before there was only a 6 inch wet spot at the corner of the rear bumper. The masonite that I can see in the ceiling about 6 inches in front of the a/c is still damp so my concern is getting it out so it doesn’t mold and mildew the entire camper. There is a soft spot on the ceiling about 8 inches behind the a/c, but I can’t tell if it is supposed to be like that or if it is water soaked.
    I am looking for a camper remediation specialist now so wish me luck. I’ll keep you guys informed on the progress.
     
    HappyTraveler likes this.
  12. WrkrBee

    WrkrBee Well-Known Member

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    When you had the AC unit out, could you see the individual layers of the roof sandwich? If so, the ends of exposed sandwich materials need to be sealed with epoxy. This will prevent any condensate from wicking into the roof sandwich materials.
     
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  13. G8tor38

    G8tor38 Member

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    I never took the unit out, I only disassembled the unit up top to get to the drain pan and coils. When I put the new ceiling in I am definitely sealing that area water tight some how.
     
  14. Sjm9911

    Sjm9911 Well-Known Member

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    The drain pan has holes in it and can clog from leaves and crap from the trees. I hit mine with a hose every so often to clear them up.
     

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