Air return ducts

[Bill M]

I have a 20th Anniversary 3855BR. When it rains I get water entering the living room's air return duct when the air conditioner is running. I can feel air coming out of duct & wondering if the is normal & has anybody else had this problem & how did you solve this? I have checked my air conditioner & everything looks good, all drain holes are free of debris, & Styrofoam cover is all intacted.

[jsb5717]

Do you have the Whisper Quiet system or do you have interior access to the plenum? Whisper Quiet makes it a little more challenging but I would be tempted to run a borescope up there when it’s leaking to see if I can spot the source.

Also, with Whisper Quiet system you don’t have the interior nuts to tighten the AC to the roof via the through-bolts. The AC anchors to the roof via lag bolts that have to be tightened from the roof after removing the cowling. Maybe they just need a little tweak to better seal the thing to the roof. Just don’t over tighten them since they could strip.

[RMcNeal]

Ours is a 2019 20th Anniversary Edition as well. If memory serves, several had problems with the AC unit not being properly centered above the hole and the seal between the unit and the roof being out of alignment and allowing water to penetrate the roof opening.
As Jeff said, you might be able to tweak the mounting bolts to get a better seal or you may need to pull the unit, realign it bolt it back down, maybe even replace the seal.

[Bill M]

Thank you, will check

[Bill M]

That makes sense, even though this problem just started. I unit sits still on a lot year round in Florida. I will check alignment, bolts & probably replace seal. Thank you