Roof Air Condensation Leak

[DKO]

One of my Dometic Penguin roof air conditioners is leaking condensation inside. It started yesterday. I took off the inside cover and checked the three mounting bolts. Two of them were loose enough that I could tighten them with the socket and my fingers. I read online that the weight of the AC can compress the gasket and the bolts can become loose.

I went on the roof today and the gasket is about an inch tall. I had my wife snug the two bolts just a little and the gasket still has plenty of room left in it. They are snug but not cranked down super tight. There is no gap between the gasket and the roof and the roof is not dipping down to cause water to pool. I took off the cover and then the sealed cover underneath to have a look. The drains on both sides of the evaporator coil are wide open. They are NOT stopped up in any way.​ Here is a picture looking straight down.​​​

​

You can see the evaportator coil in the picture above. The tray it sets in has a drain hole on each each end and a little gutter to the outside edge. The problem is that there is water pooling in the tray just forward of the evaporator coil. That tray is on the right edge in the picture above.

The water is pooling in that tray and it has no built in drain. There is no pathway for the water to travel from the tray with drains to the tray without drains. At least not that I can see. Once I close that compartment it may be blowing there some how but I have no way to see it. It does not pool in the tray that is supposed to be dry with the cover off.

​

This is a closer picture of the tray that is supposed to be dry that I am talking about.​



When I turned it on the water drained through the drain hole and gutter and off the edge of the bus like it is supposed to. I buttoned everything up and let it run. In about 3 hours it was leaking inside again. It is 90+ with sun and humidity so I will wait to go up again early tomorrow as I did this morning.​

​Any ideas how the water is getting in there and what to do to prevent it? Once that tray gets full it overflows into the screened in area. Under that screen is the inside part of the AC. From there it goes on the floor or in the ceiling. The floor I can deal with temporarily but not in the ceiling.

Thank you,

Davy​

​

[Nick Badame Refrig/ACC]

Hi Davey,

Sorry for your troubles! That's a PIA...

You are either leaking at the roof seal or the pan is failing somehow. I would guess the roof seal since
it was very loose. You may have to remove the upper unit and clean the seal then reinstall. If you have
access to an rv dealer it would be good to replace the seal in the mist of the removal.

Good Luck
Nick-

[DKO]

Thanks for taking time to read and answer. I appreciate all of the help I can get. The seal may be letting in some water. I will double check that and pull the unit if I have too. Should I replace the seal completely if I remove the unit?

I do know that the condensation is pooling in a place it is not supposed to get to and is simply overflowing from there. It is pouring into the coach without ever exiting onto the roof and then penetrating the seal.

Davy

[gene burge]

poor air flow / dirty filter , i had a brand new newmar fifth wheel a few years back with ducted air that would leak down through ceiling when extremely humid , went round & round with newmar , they had no answers , called dometic & was told there was not enough return air , i cut a residential style 14 x 14 return air filter grill in directly below a/c unit , worked great

[chessie4905]

    Make sure it isn't sitting at an angle to direct the water away from drains. I'd replace the mounting gasket while you are at it.

[Scott & Heather]

i replaced my mounting gasket and drilled the drain holes larger. Problem solved.

[luvrbus]

I never saw a Vantare conversion the roof tops drained off the roof of the bus the one I had used hoses ran from the AC through the walls down to underneath the bus

[Seangie]

Davy -

I had the same problem in a brand new AC unit where the water would pool in a tray with no drain.  I just drilled a drainhole in that tray and never had a problem after that.  I also drilled the existing drain holes larger.  Just make sure there is a good run off path for the water where you drill the drain hole or add some clear tubing to drain it away from the seal on the roof.

-Sean

[DKO]

Thanks for all the help.

poor air flow / dirty filter , i had a brand new newmar fifth wheel a few years back with ducted air that would leak down through ceiling when extremely humid , went round & round with newmar , they had no answers , called dometic & was told there was not enough return air , i cut a residential style 14 x 14 return air filter grill in directly below a/c unit , worked great

This AC is not ducted and the inside filters are clean. There is not much room for air to get through after it passes the filters. I think the inside hole in the ceiling could stand to be bigger. One thing I did not check closely while I was up there this morning was if the evaporator coil was clean. I read today that if it is not clean the fan will do weird things with the condensation water. I am in south Alabama this week and south Mississippi next week and it is very humid. This happens to be the AC we use the most during the day.

The drains holes are very big and draining good. When I ran it while up there it was draining very good and not pooling close to the gasket at all. I will have to see if I can drill a hole in the pan that is not suppose to have water.

You are probably correct about Vantare's roof air drains, Cliff. I have read that is the case. My Vantare originally had cruise airs. When they began to fail due to age it was cheaper to add four roof airs than it was to replace 2 of the 3 cruise airs. I had them added by Robert's Brothers in Springfield, TN in 2009. That is why mine drain over the side.

Davy

[luvrbus]

Thanks Davy I was wondering what was going on. I have never saw a high $$$$$$$$ Prevost conversion the roof tops drained on the roof and ran off

[DKO]

Cliff, mine has been "customized."

You mentioned a while back the best burrito to be found was in your neck of the woods. Can you give me specifics? I will be in El Mirage, AZ in two weeks and then going to Bloomington, CA near LA on I-10. When I leave CA the end of November I will probably exit via I-40. Is it any where near those routes? I have been know to plan my route around good food.

Davy

[DKO]

Up on the roof again this morning. As recommended by several places online I sprayed 409 all purpose cleaner very liberally and repeatedly on both sides of the evaporator coil. Between each application I used a spray bottle to spray water on the coil to rinse it off. It did not seem very dirty at all but at least I know it is cleaner now.

Then I used a pitcher and poured two gallons of water all over the coil letting it run down in the tray and out the drains. Jeff from East Tennessee Luxury Coach over on the PC forum suggested that and it was a good idea. This served two purposes. First, it insured the 409 was rinsed off the coil well and secondly it tested the integrity of the catch tray and drains.​

With all this water filling the tray and running through, not one drop leaked into the tray that is supposed to be dry but was full and spilling over inside the coach earlier in the week.​

I have read and been told that a clogged evaporator coil can cause the condensation to do weird things. If cleaning the evaporator coil does not fix it then I am stumped.​

DKO​

[Seangie]

Davy -  could it be from a leak in the shroud?  Rainwater?  Or maybe when the fan is blowing it blows the water of the coil into the tray?

Just thinking out loud here.

-Sean

[eagle19952]

I have had a similar problem, tho I do not have roof airs.
I have a standard 2 1/2Ton air handler, 20'x20"x 41"
Similarities: very hot, very humid and short span of cycle restart. And no previous history of condensation/water leaking/dripping where it should not.
Troubleshooting: tested cleared condensate drain tube, placed bucket under it and contained about a gallon of water in a day...
Plugged the drain hose...filled the condensate pan with water....no dripping and no leaking...
With the compressor/AC off, and fan on manual, condensate drips..

Here's what I think, I think the humidity is so high and the return air so saturated and the surrounding shrouds unable to stabilize (remain cold) etc. at a greater temperature differential that condensation drips are  inevitable and hopefully solvable...

[kyle4501]

Since is doesn't happen with the cover off, the cover is where I would be looking for a solution.
Possibilities :
- air is blowing condensate into the "dry tray"
- moisture is condensing on cover surfaces that are draining into the "dry tray".
- with the cover on, there may be a vacuum in the area that is pulling so much air in through the drain holes that water get thru. (try connecting a long hose to the drains)

If that doesn't help, with the cover off, use some cardboard to mimic the cover - look for things that change the air flow. Consider options to cause small disruptions in the air flow to see if that makes a difference.

Good luck &
please Keep us posted.