water entering airstream from around dometic air conditioner, not condensate water

[Lucky Tom]

I want to check the seal between the dometic air conditioner and the roof. water enters into airstream from blowing rain or water hose from washing top.

Do I check this by removing the bottom cover? And if so, does any screws have to come out other than the two that are obvious, one at each end in the center?

[Belegedhel]

It depends on how your AC is set up to collect the condensate. If it is mounted in a plastic "pan", then the foam seal will not be visible from outside. If it uses the two "cups" to catch the condensate, then the foam seals should be visible from the outside. If visible from outside, you will need a ladder so that you can get up high enough to see what is going on.


If your AC is mounted in the plastic pan, then you should still have a good look at the outside of the pan, as cracks in the plastic pan might result in water leaks to the interior. To see the seal, you will have to remove the plastic "ceiling" unit. Once this is out of the way, you can try to look up through the hole in the roof and try to see the foam seal from the inside. You might have to remove the interior part of the ceiling unit that clamps the exterior part to the roof. There are typically just 3-4 long bolts that clamp the AC down. Be wary of the wiring--would be best to throw the breaker for the AC before you start any disassembly.

good luck!

[HHPJ]

Out of curiosity, what year is your Airstream?

[Lucky Tom]

I have found all the screws, now the bottom cover is off. I see the bolts which hold the unit to the roof.

[Lucky Tom]

2009 Flying cloud, 23 ft. I now have the bottom cover off.

[vintagemotor]

If you have a leaky seal, I have done this several times.
And no, just tightening the 4 big mounting bolts will not fix the leak.
You need to replace the seal between the AC unit and the roof of your AS, by first disconnecting any power(AC) to the AS, then loosen the 4 big mounting bolts by 3-5 inches.
Climb up on top very carefully only stepping on seams and rivets to be safe, and lift up the AC unit until you can get a 4x4 under the front and back.
Scrape off the old seal and clean, install new seal and put everything back together, be very careful not to over-tighten the mounting bolts as this will cause a new leak.

Not the easiest, but not the hardest either, I'm sure that there is an install video on youtube to watch as well.

Good luck and happy Airstreaming!

[A W Warn]

Originally Posted by Lucky Tom

I want to check the seal between the dometic air conditioner and the roof. water enters into airstream from blowing rain or water hose from washing top.

Do I check this by removing the bottom cover? And if so, does any screws have to come out other than the two that are obvious, one at each end in the center?

In the 2009, according to the parts manual for that model, the air conditioner sets inside a plastic pan. The AC condensate and any rain that finds it's way in should collect in the pan and be directed to the drain tube.
What I would do:
1. Look at the drain tube to make sure water is draining below the trailer. If the tube gets blocked water will overflow the pan and drain inside. Unclog using weed whacker string as a probe, or low pressure compressed air into the end of the tube.
2. If water is coming out of the drain tube and flowing freely, this is the next step: Remove the interior cover. You will see the drain pan has a crossover, a black plastic trough, that connects to the drain tube. Look for cracks/leaks. You may be able to reseal (caulk, epoxy, etc) a crack or loose connection.
Also check the bolts for correct torque. Look for 3 or 4 bolts that can be tightened to clamp the AC unit down onto the seal/pan.
3. If the above does not fix it, you are looking at either a new pan and seal or new drain cups and seals. The AC has to be removed for this repair. (I recommend the cups. I've done both)

[Lucky Tom]

I am getting somewhere. The three very long bolts are out now and the large gray plastic pan has been removed. I see somebody has worked on this before to try and stop the leak, a lot of sealant has been used from the bottom and it appears to be typical silicone sealant. The black plastic trough which sits just below the evaporator coil does have a tiny crack but not much water coming through. By the abundant use of sealant from the bottom somebody has tried to repair this leak by just squirting. More later, need to assess where the water is coming through. Will try to seal the small leak in the evaporator coil condensate try.
Is the torque as I replace the three bolts so critical that there is a given torque setting for my wrench?

[A W Warn]

This thread shows some of my experience with pan replacement. (I recommend using drain cups instead of replacing the pan, if you have to)
http://www.airforums.com/forums/f44/...ml#post1309346

[Burnside Bob]

Hi Tom & Phyllis:

On a 2009 Airstream the AC unit was placed on a plastic pan or tray. The tray is caulked down to the top of the trailer and has a raised lip that fits into the AC opening. IMOP it is not likely that the tray and/or the caulk it is bedded in has failed.

A more likely source of your leak is a plugged drain line. Condensation from the AC, plus any water entering the AC's shroud thru its ventilation holes collects in a reservoir which drains thru a 1/2" diameter hose routed to the road side wheel well. If the reservoir can't drain, you will have a leak inside your trailer.

If you remove the AC diffuser inside your trailer, you should see the reservoir, which was white on my unit. You want to disconnect the drain line and blow air or water thru it to make sure it is not plugged. If it is plugged, and air/water under pressure doesn't dislodge the plug, try running an electrician's fish tape thru the drain line. You can go at the drain line with the fish tape from both the AC and the wheel well ends, but only try to clear the drain line with compressed air or water from inside to outside.

Hopefully this is your problem. Good luck!!

[Lucky Tom]

After a storm has delivered driving winds and rain is when we see the water, however this is not often. The average rain never gets inside. Now that I see the tiny crack in the trough near where the tubing hooks up tells me this is where the small amount of condensate water is coming from. Thanks to all who advised.

[Airpower]

I have a leaking pan, came from the factory busted up and has been caulked several times. What are the "cups" you speak of sir?

[pmclemore]

I bought my 30' International used. The PO had the second ac installed at the rear vent opening, as is common. I had not had it very long when we noticed that the ac leaked onto the bed when it rained.

Fortunately for us, I was having the ac removed anyway, as we didn't want an ac over the bed. When Lewster removed it, he saw what the problem was: The ac install required two "doughnut" gaskets in order to make a good compression seal. The installer only used one, which meant that there was not enough "gasket" to tighten down against.

Hope this is not your problem but I wanted to mention it just in case.

Pat

[A W Warn]

Originally Posted by Airpower

I have a leaking pan, came from the factory busted up and has been caulked several times. What are the "cups" you speak of sir?

https://www.amazon.com/Dometic-31076.../dp/B003BIR9VQ
In the bottom of the AC housing there are two holes that let the condensate drip out. These holes are outside the 14" x 14" opening where air comes through, so if not directed to the drain tube the condensate would run onto the roof and create stains. Airstream's first solution was a big pan that fit the curved roof which the AC unit set into that caught this water. The new/better solution it to fasten the two cups beneath those holes, then water is directed from the cups through small pipes to the factory installed condensate drain tube.