New Dometic AC Unit condensation problem...help!

[badkat]

We had a new AC Dometic AC installed in April 2020. After we started using it about 2 weeks later water was dropping to the floor from the return air.

The tech that installed it came out and called Dometic and they said negative air flow/improper installation. He disagreed with that...got rid of the water on the roof and had us close the bottom vents.

Well no water for about 2 weeks then boom the water fall started again. Also outside our concrete pad is soaked unlike everyone else here and we are all Airstreams here at Top of GA.

I called them today and they are trying to figure it out.

Any feedback please.

BadKat

[n2916s]

on my ‘86, when I had the A/C replaced, they used two foam gaskets instead of one to allow for the water collection cups to sit under the unit with the bolts torqued down adequately. The previous unit had used a collection tray.

Never leaked a drop.

[jimmini]

Our new Dometic AC runs water off the roof when humidity is high.
Dometic use to have a good reputation but now products are poor and no support.
Our new Dometic frig had lots of problem that dealer had to put up with and the crisper drawers are to small to hold a pound of bacon because they are not deep enough yet there is room for deeper ones.
But the worst is our new Dometic high toilet when I sit on it my personal part are in what ever I have left in bowel that is not deep enough.
No more Dometic junk I spent a lot of $$$ to learn this.

[Belegedhel]

Well, there are a few things that come to mind as possible problems.

First and most obvious is a leaking/poorly installed condensate catch mechanism. Back in the day, there was a plastic pan that was installed under the AC, and the place where the tube met the plastic was notorious for cracking. Now, some "cups" are usually installed underneath the AC drip holes, and they send the condensate in via tubes that have to pass through the (usually doubled) foam gasket before meeting the main drain line. You could test whether this is the issue by disconnecting the cups or drain lines from outside and letting the condensate run down the outside of the trailer.

Assuming everything was installed properly, evaluate whether you get more or less dripping to the interior when the fan is running on high speed vs. low. Reason I bring this up is that we used to use Coleman AC units on our oilfield workshops in the Gulf of Mexico, and you had to keep the fan running on full blast all the time, or you would end up with icebergs developing on the evaporator coil, and first you would get reduced air flow and cooling, and then you would get a shower as the iceberg melted. This was generally aggravated by people opening and closing the door constantly so that there was always fresh humid air in the cabin. This brings us to the next possibility:

Make sure all your door and window seals are in good shape and that you aren't sucking warm humid air into the coach all the time. The second place to check is the seals under the AC, and the AC itself. In theory, you have a closed system, and as you cool the interior air, the humidity comes out of that air in the form of condensate that goes down the condensate drain tube. But, if you cool the interior of the AC down nicely, but keep leaking humid air into the AC, the humidity may condense on any number of cool surfaces and drip into the coach, instead of getting pulled out by the evaporator coil. I found on my AC that was 5 or 6 years old, that the butyl-goo they had sealed a hole that allowed electric wires to pass through had slumped and opened up a nice passage for humid air to come directly into the AC from outside. I got that patched up, and no more dripping AC.

good luck!

[badkat]

So the Dometic Penquin II should not have a collection pan but cups. He left my collection pan when the unit was installed.

Need to know to get this fixed properly. Thanks for any help.

BadKat

[Belegedhel]

Hmmm. I think I have a low profile Dometic Penguin II, and I probably bought one of the last condensate collection pans in order to do my installation (but this was several years ago). As long as the pan is not cracked, and the nipple that connects the pan to the drain tube in in good shape, it all should work. Question is whether all that was hooked up correctly.

The cups have become the new standard, but that isn't to say the old pan can't work. Anyway, if you are a hands-on type, you can probably drop the ceiling unit and see what is going on up there.

good luck!

[badkat]

Thanks for the comment. The installation tech is coming out again. He said there has been so much humidity so that causes so much condensation. I a at Top of GA and I have friends that's units are not condensing like this. My old unit did not do this.

Hopefully we can get this resolved. I know he called Dometic and they said it was installed wrong. I just happen to hear his conversation with them. He does not think so.

[Belegedhel]

If you are getting considerably more condensate than your neighbors, then it suggests that your AC is sucking in warm humid air from outside. The obvious place for this to happen would be at the foam seal, but it could be the unit itself as described above.

good luck!