A/C condensate water dripping from return grille

[Steverino]

Hi all,

I had posted in a separate thread about our dying roof air unit. I bought a new one and successfully installed it myself. All was going reasonably well until today, when I decided to run the air while giving the inside of the rig a thorough cleaning.

After running it for maybe an hour or two, I discovered quite a lot of condensation dripping from the main ceiling grille (this is a ducted rig). I took the grille and sheetmetal cover off and found that there was a lot of sweat accumulated on the metal surfaces of the A/C unit, and also on the tubular metal framework that Jayco uses to reinforce that part of the ceiling opening.

I'm guessing this isn't exactly normal, but I'm not really sure what one does about it, and I don't see anything obviously wrong. Does anyone else have this problem? There is "normal" condensate dripping steadily off the roof exterior (as you would expect), so I don't think its a case of the regular condensate getting into the interior. I think it's only sweat generated from the inside / bottom surfaces of the A/C unit.

Any thoughts?

Thanks very much!

[Rustic Eagle]

My first thought would be that there is something blocking a "free flow" of all the condensation to the outside of the unit (?).

Could the new foam seal be compromised, or the four screws not tightened correctly, thus the condensation from the roof is getting back in??

Bob

[RedHorse1]

Rustic has a good point about condensate finding its way back in but if you are sure that's not the case it must be from the humidity inside the TT. Were you wet mopping or doing something that would add a lot of moisture to the inside? There might also be an air leak letting outside air into the evaporator and bringing extra humidity into the airflow.
I'd try running it a few hours without anything else going on to see if it drys the air out and the condensation stops.

[Steverino]

Thanks to you both for the suggestions. I'm going on the roof today & take off the cover & have a look around. I'm pretty confident the main square seal to the roof is good, and my bolts are good and snug, however I'll re-examine and/or pull the unit to be sure. I do want to see where the pan drains are & if there's any reason they wouldn't be fully draining properly. I'll also check for the possibility of outside air leaks.

I was wiping the interior walls down with a damp (not dripping wet) cloth, and the outdoor humidity was relatively high yesterday - so maybe that's all it is. I was just a bit surprised at how much water was coming out - a few drips I wouldn't have thought much about. But as I've said elsewhere, this is our first MH and first roof air - our last trailer had a side A/C, so any & all condensation automatically went in the pan. This is different and I am still learning what to expect.

[Steverino]

...another quick update: got up on the roof and pulled things apart, including the sheetmetal cover over the evaporator. It all seems fine, and the drains under the plastic evaporator pan (to the rooftop) both had water drips on them from yesterday, so I think they're working. I did re-smoosh the "dumgum" that seals a couple of corners, just in case. Also added a bit more aluminum duct tape to a couple of places where I thought outside air might get in. On the inside, I used some Great Stuff expanding foam to seal a couple of spots in the roof cavity where air could get from the A/C side back to the return side. I doubt that was causing trouble, but you never know.

I'm gonna run it for a while today & see what happens. I'm betting it's also made worse if you expect it to cool a humid interior from 85 to 75 without any breaks or steps. Letting the fan run between A/C cycles would move air & allow things to dry out somewhat. We'll see...

[Steverino]

...aaaand yet another update. (Sick of me yet?) Looks like all of the water is on the blower side, not the return side. There's condensation on the metal as well as the white styrofoam around the blower fan. I'm also wondering if the fan is actually pulling some moisture off of the evaporator core and flinging it into the plenum area & ductwork.

Decided to try running the fan on low (vs. high) to see if moving less air would reduce the water accumulation.

[Rustic Eagle]

Originally Posted by Steverino

...aaaand yet another update. (Sick of me yet?)......snip

Steve,

Nope..., updates are part of the forum process that helps others, plus gives others ideas of what to look for.

If you run out of options to check into and the problem persists, I would give the A/C manufacture a call and see what their tech guys say.

Bob

[Steverino]

Thanks Bob. I did send an email today to AirExcel (which makes the Coleman units). Haven't heard anything yet. On an unrelated note, I just have to say I've had great success with Jayco's customer service - just today they emailed me several wiring diagrams I needed to help sort out some electrical mysteries...

[exjay1]

Fighting the same AC battle, pls keep us posted (expecially if they respond back to you)