Water a/c vents

[patmo2000]

Hello to you, has it ever happened to someone that water falls through the a/c rear air vents on the roof. At first I was thinking about condensation but there is still enough water to wet the ceiling. Just the one behind the unit.
My unit is 3121 legacy 2022

[Rotnjonny]

Now that is interesting. I have not experienced that situation. I would think the only way that could happen would be if the a/c unit wasn’t properly sealed u you o the roof during installation. I suspect that a few of the gents with vast tech experience will weigh in as well.

[jimcol]

We had it it happen once. Camping for three days with 90+ temps and 90+ humidity when the vent over the vanity starting running like Niagara Falls. Well it was dripping water. Removed the louvered vent cover and could see inside the duct work. It had separated at a seam and was mixing unconditioned attic air with chilled AC air. Turned off the AC and let the fan blow on high for a couple of hours to dry out the duct work. Was able to pull the seams close together and hold in place with aluminum duct tape. Applied several overlapping lawyers. It has held for years, was still good in May when we sold the unit.

[Rhortie1]

Originally Posted by patmo2000

Hello to you, has it ever happened to someone that water falls through the a/c rear air vents on the roof. At first I was thinking about condensation but there is still enough water to wet the ceiling. Just the one behind the unit.
My unit is 3121 legacy 2022

We had that happen to us when our Rv was new but only when it rained. It came in through the a/c intake vents. I was told by my dealer that “a/c unity’s are not water proof only water resistant “. They fixed the leak and I haven’t had a problem since. Never had any condensation problems. Good luck

[Mikendebbie]

Just a theory to explore...I have no experience with this.
It seems like condensate water might be able to run into the ducts given the right circumstances...for example - if the roof gasket is not adhered to the roof membrane in just the right spot as illustrated in my sketch and the screen shot.
The solution would be to pull the AC unit, install a new gasket and re-mount the AC.

[RMcNeal]

Originally Posted by jimcol

We had it it happen once. Camping for three days with 90+ temps and 90+ humidity when the vent over the vanity starting running like Niagara Falls. Well it was dripping water. Removed the louvered vent cover and could see inside the duct work. It had separated at a seam and was mixing unconditioned attic air with chilled AC air. Turned off the AC and let the fan blow on high for a couple of hours to dry out the duct work. Was able to pull the seams close together and hold in place with aluminum duct tape. Applied several overlapping lawyers. It has held for years, was still good in May when we sold the unit.

At least you found a good use for some lawyers.

[jimcol]

Originally Posted by RMcNeal

At least you found a good use for some lawyers.

Well, evidently I didn't proof read that too well. Layer/lawyer, could have saved myself a key stroke.

[phillyg]

If it's from the return vents I'm surprised this problem hasn't been resolved, as it's been reported since 2015 or so. It's not the big donut, rather it's a failure of all the drain holes not being reamed out by the mfgr. There's a tech bulletin around from another mfgr. about how to address the problem.

[Daryles]

The TSB regarding the AC drip pan drain holes is in the files section

https://www.montanaowners.com/forums...?do=file&id=52

[Kyle and Lisa]

Yearly maintenance is to tighten the four bolts that mount the a/c to the roof and check your drainage hole. Otherwise, the water has nowhere else to go but down.

[catch up with the zzzz]

I think the important question is weather it is acutally comming from the vent or cold air return. I had a leak, only during the heaviest,rain. water would drip from the cold air return, not wetting the filter buck was just dripping from the edge of the housing. I found 2 screws in the roof had perforated the tpo. Located near where vents are located from too long of screws and only presented themselves after serveral thousand miles of rough interstates.

[c2itcliff]

I was able to resolve this problem by replacing the AC mounting screws (4) with stainless steel and plenty of dicore lapseal. The issue isn't the seal, it's the steel lag bolts used. As they rust,vits allowing water to enter the roof into the air intake plenum and drips onto your floor. Simple fix...remove the top cover of your AC, look for the four lag screws. Remove and replace with new stainless steel. Coat the threads with lap sealant and/use a Qtip to push sealant into the screw holes. Don't over tighten, just snug will do. It fixed mine on the rear, still have to do the front although it's not leaking yet. Probably because it's a flat surface.