Roof A/C drains into rig after it's shut off

[biggrock1]

Sent: 7/16/2007

I have a little question for you guys.
Why would my air conditioner start to drain inside after I shut it off? It was very hot and I was working on the plumbing inside (do this every year) and when I finished for the night at 11:00 and shut everything down my A/C started emptying inside adding a little more water to an already wet carpet.
All explanations accepted and appreciated
before I tackle this additional problem tonight.
Thanx
Howie

[firehart2]

Sent: 7/16/2007

Does it have a drain tube? Maybe its plugged. It may have a drain pan like a fridge has. Was it raining outside or was it really humid outside?

[biggrock1]

Sent: 7/16/2007 2:08 PM

it was raining earlier

[denisondc]

Sent: 7/16/2007

The reason it doesn't drain water into the interior each time (and all the time) it is used is because the condensation is supposed to be able to drain to the outer part of the unit, and then onto the roof, and run to the ground like the rain should. This works fine if the roof is FLAT. Once the roof has sagged a little, the condensation will just form a pool around the gasket that surrounds the 14" square entry hole in the ceiling. If there is enough of that condensation to flow over that gasket (and there will be after running for a couple of hours), or after a minor rain, then the water will make its way inside. The action of the circulating fan probably kept some of the water from running back in - until you shut it off.
One quick technique is to park the RV on a slight tilt. I measured my roof sag - it was 3/4" last winter. It is parked with the wheels on the 'curb' side sitting on 2 by 10 planks. This keeps it tilted about 3 degrees - enough so the water isn't forming a pond up on top. Ponds are heavy, and will increase the sag, plus keep the roof structure wet from the watter soaking in at the seams or at pinholes in the aluminum.
Making sure the gasket under the a.c. unit is in perfect shape will help - unless the sagging is more than the vertical dimension of the gasket.
Our Winnie not only sits parked tilted 3 degrees, but when not in use we keep a 2 by 4 pillar in it - with a load spreader at the floor and the ceiling. This is to keep the roof sag from getting worse, and hopefully to let it 'unsag' eventually.

[Rayd]

Sent: 7/17/2007

All those ^ good answers and ice build up the lines melts after you turn the unit off.

[biggrock1]

Sent: 7/17/2007

I am guessing that denison has hit the nail on the head because the deluge was immediate upon shutting the A/C off.

[DanD2Soon]

Sent: 7/18/2007

Like Dave, we keep ours on a slight grade too.  When you get ready to tackle it, these old threads may provide some useful info:    CW 1890 - Roof A/C leaks   &   CW 1949 - Roof A/C seal replacement     

Good luck Howie