A/C drips through ceiling

[WejaZ28]

I have a 96' Newmar Dutchstar with a single 15,000 unit and ceiling ducting that runs the length of the RV. Water leaks through ceiling in different spots after prolonged A/C use.

I replaced the A/C unit seal, checked pan for cracks or leaks etc...I also noticed that the electric heater which is just after the condenser is covered in rust. Problem seems to worsen after showers and cooking(more humidity I suspect).

I am almost certain the problem is that when the condenser cycles(turns off), the fan blows the the melting water from the coils into the air duct and along the length of the RV. It will then leak out of the ceiling via the air duct on whatever side of the RV is lower.

My question: Is there any way to prevent or catch the water prior to making it's way in to the vents and dripping out the ceiling.

I suppose having the A/C unit shut down when cycling is one way but we prefer to have the fan stay on during the cycling to utilize the cool air beween cycles and wear and tear on the unit being restarted.

Thanks, Kevin

[Jackm]

This is from experience. Your AC has a drip pan that sits beneath the evaporator coil. The pan has a hole at each end to drain out the excess water (onto the roof of your RV). In all probability, your evaporator has become dirty and has subsequently plugged one or both of these holes. It's a hassle to fix but in short, you have to access the evaporator coil, clean it with something strong like 409 and a brush, clean out the drip pan, and unplug the holes. When I did this, I trashed the inside of the RV with dirty water. Some other forum member may have some trick for avoiding the mess. In any case, this is probably what's happening. The greater the humidity, the worse the problem becomes. Best of luck. Let me know if you need any more info.

Jack

[WejaZ28]

Thanks for the reply Jack.

I inspected the catch tray when the unit was removed for a new seal and tested the catch tray beneath the evaporator. I poured water all around the unit and it drains out both sides of the tray. I even extended the dump spots further away from the unit to be sure.

As indicated in my post, I really think the melting water is being blown into the roof ducting area, as indicated by all the rust on the heating wires in front of the unit.

There is a square, thin diaper like material beneath the unit on the bottem of the vent duct. Not nearly enough to soak up any amount of water.

Any more thoughts are appreciated.

Kevin

[Jackm]

It's times like this that a white board would be handy. Does the problem occur when the unit is allowed to shut down after cycling? In other words, can you prevent the problem by not running the fan all the time? Thanks.

Jack

["007"]

Your post #1 & #3 indicate what I would be sure in doing.
When you installed the new seal under AC did you slope the AC 1/4" towards your drain holes so when and if condenser drips water, water will drain out towards drain holes.
If any water stands in the drip pan the blower will blow standing water in pan into your duct system.
Here is a PDF of your DUO-THERM system.
There is more information in the Quick Tips & Mods link.

[lonestarace]

Is your evaparator freezing up? If so, Dometic makes an anti-ice probe that stabs between the fins of the evaparator and is plugged into the curcuit board. It is suppose to cycle the compressor off before the evaparator freezes up so you won't have your problem.

We hope this helps

Don

[wa8yxm]

Old thread.. One problem I have had that caused the AC to drip is being non level.. Normal operation water will condense out on the AC's Evaporator coils (The indoor or cold coils) and drip into a drip pan under the AC.. The water then runs to the rear of the AC where it either runs under the condenser (HOT) coils or, drips out onto the roof and runs down the sides.

Now... If the rig is a bit "Nose down" the water may drip off the FRONT of the plastic drip tray instead of the overflow port at the rear.

When I re-leveled, raising the nose just an inch or two.. Fixed the problem.

[WejaZ28]

Thanks for all the replys. Yes, the A/C is tilted slightly towards the drains. I do feel the evaporator is freezing from time to time.

I also recall that it seems to happen mostly at night as opposed to daytime.

Don, Do you have a link to the anti-freezing probe you spoke about. If I keep water from freezing there, then maybe there wont be as much to be blown into the rig.

Thanks again everyone, Kevin

[lonestarace]

If you have a DuoTherm go to the link 007 privided in his post.
If your unit is a heat pump, there should NOT be a freeze control sensor.
http://bryantrv.com/docs2/docs/acservice.pdf.
I saw some info on the freeze control on p.30 of this file.
You could also call Dometics tech line 800-216-5115