AC leaking when running combined with heavy rain

[srgallan]

Hi folks,

Question I wanted to post to the group here as I try to find more information sources. Picked up used 2019 TT August last year and noticed this year that if the AC is running and we have a lot of rain we see water dripping inside. If not running during the rain there is no water.

I already had mobile service from the dealer come here and say they could not find anything and drain was not clogged and last time they ran into this a new AC was installed to fix it. He did clean the drain a bit.

My thought if it was to happen again to have a new gasket installed if possible but have no ideas. Any suggestions?

[JRscooby]

trailer_newbe wrote:

srgallan wrote:
Thanks for all the replies, sorry it took so long to get back. It was the mounting bolts that got loose so really appreciate the feedback. I will indeed put on some thread lock.

Keep in mind, the bolts likely loosened because the gasket compressed over time. In other words you’ll likely need to do it again some point down the road. I wouldn’t put thread locker on the bolts because they aren’t actually backing out, rather the gasket compressed.

Thread locker will make it more likely for the bolt to break next time the gasket compresses. If you think the bolts are backing out, pull 1 at a time, put rubber washer on them.
BTW, would AC running or not change the path for water under the gasket?

[trailer_newbe]

srgallan wrote:
Thanks for all the replies, sorry it took so long to get back. It was the mounting bolts that got loose so really appreciate the feedback. I will indeed put on some thread lock.

Keep in mind, the bolts likely loosened because the gasket compressed over time. In other words you’ll likely need to do it again some point down the road. I wouldn’t put thread locker on the bolts because they aren’t actually backing out, rather the gasket compressed.

[ScottG]

Have you gone up on the roof and checked the AC cover for cracks or damage?

[srgallan]

Thanks for all the replies, sorry it took so long to get back. It was the mounting bolts that got loose so really appreciate the feedback. I will indeed put on some thread lock.

[deltabravo]

Condensation drain holes in the base pan could be plugged up. If that happens, it might be possible for that condensation (or rain water) to overfill the base pan and run in to the RV, depending on the design and brand of the A/C you have.

Another common thing is that the mounting bolts have worked loose.
It's happened to me several times, then rain water leaks inside around the gasket.
The second time it happened, I added blue thread lock to the bolts.
Here's how to do it.

After that incident, now I preemptively install thread lock on the bolts right after I buy an RV. I do that as I go through every system and fix / improve things that the factory or dealer didn't do correctly.

[srgallan]

@Grit Dog: So the issue being I am just there on weekends so coordinating me being there during rain is not always accessible but trying so I can take a look. So far I have only seen it leak during Rain with AC on. With AC off I did not see any water coming down, but it does not mean that it was not. I say this being it seems water has followed along one of the ceiling panel tracks to the wall above my slide. It looks fairly early on still but I have detected some moisture there now. So the drip could be along the seal and only visible when AC runs being it pushes some out of the grates making it visible. This issue still looks fairly new based on what I can assess so far.

@all - can I drill a small 1" hole in the ceiling panel close to slide to get inspection camera up there without damaging anything? I have some moisture now to deal with and I expect a fall service.

[Grit_dog]

Lots of jumping around here. Stay on diagnosing for a sec.
Have you been in a heavy rainstorm without the AC running? Does it still leak? Did you try to make it leak with a garden hose spraying the roof/aC?
Because if it’s an external leak (gasket likely or possibly a thing else idk what) that should have nothing to do with whether the aC is running or not. It can’t suck in the rain as it doesn’t pull outside air in.
But as mentioned it’s possible it’s just condensation from being 105deg and 169% humidity lol.
But yes the most likely leak location is around the gasket. Either too loose, over squished or maybe it’s rolled or pinched. Could a been like that since new.

[JRscooby]

If you take the inside cover off to get to the bolts, you will likely see how the warm, moist air from the intake can contact the cold surfaces.
Maybe next rain, drop the cover, find source of water?


Lazy man idea about re-installing the 4 bolts; (Young person may have no issue, but many in my age group have problems working overhead) They are long, for diameter, and not a lot to guide the top end to hole. And while you are trying to get them started, you are holding the plate up and in place. I took a couple pieces of all-thread (1/4-20, IIRC) longer than bolts, screwed them into holes. Much easier to start nuts, and the studs hold plate up while start 2 bolts. Double nut to remove studs, replace with bolts

[MFL]

An actual mobile tech, with just basic knowledge, should have already viewed existing gasket, snugged bolts if needed, or suggested replacing the gasket.

Often times an RV that is just a few years old will need bolts snugged up. If you install a new gasket, snug it properly, it too will likely need a bit more tightening, after a couple years of towing, and vibration.

Jerry

[opnspaces]

You're not removing the AC. You are just removing the 4 screws holding the panel up on the ceiling inside the trailer. Once the panel is down you should see the four bolts that go straight up through the roof.

[enblethen]

TXiceman is correct to a point. Coleman units have four bolts. They have a spring around the bolts to keep unit tight as the gasket compresses. You have to urn bolts like 4-? turns so snug it up.
Bolts are accessed from the interior of the rig by removing ceiling unit.

[srgallan]

Thanks all, appreciate the input. I have never removed the AC unit so will spend some time googling that and give it a go with a friend to see if that fixes it.

@enblethen - it's a Coleman Mach 1

[JRscooby]

First, is water leaking in, or is it condensing inside the unit and dripping? When mine starts that I open a high window, and rig a fan to blow out. Normally stops fairly soon.

[TXiceman]

Don't over tighten the 4 bolts as this will crush the gasket. Tighten no moe than one fill turn on each.

If this does not stop the leaking, you will need to remove the a/C unit and replace the gasket. DO NOT caulk the gasket. The gasket should not be tighten more than what it takes to compress the gasket by 1/2. Tighten all 4 bolts equally.

Ken