Dometic Air Conditioner Condensate

[thompsonkd]

We have the older style Dometic AC, and the tubes or cups that drain condensation away seem to be clogged. Water drips from the AC when running. How do I clean out the tubes, and I think that there are cups on the roof that also need cleaning? Thanks in advance. 
David

[Geronimo John]

I would start by vacuuming the discharge hose just behind the street side rear tire.

If no Joy then:

• Remove the air distribution cover inside your Ollie, you will see two tubes that come into the 14" X 14" roof penetration.  Suggest you disconnect at the "T" that connect the two tubes (from the small drain cups that are outside the roof penetration) and the line that drains down.  Then vacuum suck out the contamination/crud that way. 
• If that does not work try a copper wire with the end bent so as not to poke a hole. 
• If that does not work, you likely will need to remove the Dometic and service the cups and lines from above. 

GJ

[thompsonkd]

Thank you very much for the ideas. We have taken the air distribution cover off, and used a weed eater line to poke around in the tubes. We ran the AC with the cover off, and determined that it was just one side that was blocked. Water seems to come out of one of the cups, and flows easily to the outside. I like the idea of a copper line-I’ll give that a try. Weed eater string is too flexible to really work. I actually took off the shroud up top, and there was a piece of styrofoam protecting the fins, so I took that off. Then there’s a piece of plastic that covers what I guess is a condenser? Anyway, at that point, I could see the cups, but couldn’t access them enough to clean them. I didn’t feel comfortable enough taking anything else off. I’ll try the copper line inside the Oliver, and if that doesn’t work, I think I am stuck. Seems like there must be an easy way to annually clean the cups? Water leaked out of the AC to the inside, but the position of the AC unit just put the water onto the floor-no problems. 

[Geronimo John]

17 hours ago, thompsonkd said:

, and if that doesn’t work, I think I am stuc

Great effort.  I did not want to bring out my big gun, hoping that the other more benign approaches would work.

If all else fails, unplug the "T" and blast the plugged line with 30 PSI air via an air nozzle.

WARNING:  There is a potential that you may blow off the air line connection at the cup. 

On 2/25/2023 at 3:01 PM, thompsonkd said:

Water drips from the AC when running

 Should have verified this first:  I am assuming that the water is dripping onto the outside of your Ollie, not through into the cabin.  Please confirm.

[thompsonkd]

Water is running into the cabin of the Oliver, following the tube from that side of the Oliver. Water also runs down the side of the trailer from the cup on that side of the trailer. I put a towel underneath the cup and the capillary action allowed us to run the AC as a test for about 15 minutes. After the towel was saturated, water began to come into the trailer along the tube. The other side seems to work, and water travels the tube to the drain underneath the trailer. My wife posted a video on the Oliver  Facebook page, and Jason from service replied, thinking that it was the seal between the cup and the tube. Thanks for your replies. 

[mountainoliver]

My condensate tubing used to plug up on a regular basis. One of the tubes located in the ac inlet area just behind the inlet filter was slightly kinked and wouldn’t drain well so would plug up often. Once I straightened that out I’ve not had any issues. To clear the plugged line before I eliminated the kink, I used a short section of 3/4 in heater hose and adapted it to a garden hose. The heater hose fit perfectly over the condensation drain underneath the trailer so I would simply back flush the drain line. The water would overflow the cups forcing built up crud out onto the roof. You should also make sure that the soft caulking that’s around the two drain hoses as they go through the roof seal (just behind the ac inlet grill/filter) to the cups is complete. Otherwise water from the cups can wick back into the trailer and drip through the inlet grill and onto the floor. 

[thompsonkd]

Good idea about flushing the line with water! When you mention the soft caulking that’s around the two drain hoses…you are referring to the caulking inside the trailer, correct? That may be part of the issue, but the cup seems to be blocked as well. How would I access the tube as it connects to the cup, to make sure it’s clear, and completely attached? Once the housing inside the trailer is off, I can trace the tubes into the foam but can’t see or access the cups. I couldn’t see or access the cups from top either? Thanks again!

[mountainoliver]

Yes, as the tube enters the foam gasket to attach to the cups. Make sure that butyl caulk is still sticky and is firmly stuck to both the foam and the drain tubing. You don’t need to worry about the tubing itself being clogged somewhere, the back flush will blow out all of the crud growth in the tubing. I also used a stainless worm type hose clamp to make sure that the heater hose (or whatever type hose) is firmly attached to the Oliver condensation drain. Also don’t worry about access to the cups, the water will flush everything and actually overflows the cups onto the roof. I wouldn’t run the water at a high flow or for much longer than just a few seconds, probably less than a minute is gracious plenty to get er done. 

[SteveCr]

2021 LE2  ....

Some pics of my Dometic.......recently uninstalled. Maybe this helps. In the pics you will see there are two layers of foam gasket plus the butyl tape that seals the AC to the roof.  The tube penetrates the foam gasket attached directly to the AC. The penetrations are sealed with not butyl tape but something that feels like expandable foam....not sticky at all. 

When my LE2 was new the AC leaked condensate into the trailer. A repairman determined it was leaking at the "T" connection because of a miss applied clamp. It took him <30 minute to repair. Oliver paid for the repair.

Let me know if you need more pics. (this unit is for sale)

Steve

[thompsonkd]

Thanks for the pictures. They are very helpful. It looks like that expandable foam that seals the tube as it goes through the foam gaskets present on your AC, is not on ours. Not sure why. Condensate is definitely backing up from the cup, and following the tube into the trailer. Thanks again for the pictures. We’ll keep investigating. 
David

[mossemi]

On 2/25/2023 at 8:01 PM, thompsonkd said:

We have the older style Dometic AC, and the tubes or cups that drain condensation away seem to be clogged. Water drips from the AC when running. How do I clean out the tubes, and I think that there are cups on the roof that also need cleaning? Thanks in advance. 
David

 

I noticed AC condensate water dripping off the rear curb side roof at a COE campground along the Arkansas River and chalked it up the the high humidity we were experiencing.  The next day we were at Choctaw Lake in Mississippi and the water started running off over the curb side window.  After experimenting with leveling the trailer, I found that when the curb side was low, the water ran off that side.  I could move the runoff water to the rear by raising the nose.  And best of all , I could stop all roof runoff by raising the curb side and all of the water drained from condensate drain tube.  We did some troubleshooting at home and found that water would leak from the curb side condensate drain cup whenever the curb side was low.  I finally found a posting on the Airstream forum about installing the drain pan kit.  I ordered the kit and an extra foam gasket.  I completed the drain kit installation when I gained access to a shop and could take my time removing the AC and find out the source of the leak, which was a broken nipple on the curb side drain cup.

 

I don’t know if this will have any bearing on your issue, but I know my troubleshooting took me in a different direction than I was heading in at the very start.

Mossey

[thompsonkd]

That’s helpful, Mossemi. So, to get access to the drain pans, the AC has to come off the roof, correct? We are beginning to think the drain pan may be damaged somehow, not allowing a full connection of the drain tube. 
Thanks

David

[mossemi]

Yes it does need to be raised enough to remove the screws that the cups are attached with.  You can see the screws in Steve’s picture.  I flipped mine over on its back while it was still on the roof.  That made it a little easier to remove the old gasket and sealant.  But before removing or raising the AC, you should remove the plastic evaporator cover under the foam insulation.  That will allow you troubleshoot a little further.  It is attached with press in tabs around the perimeter and a few screws.  I was then able to use a measuring cup to put water into the drain channels to pinpoint the leak.

Mossey

 

[Steph and Dud B]

Our curbside drain line just stopped and the water is draining down the side of the trailer. As a quick fix onsite, can I simply direct a jet of water from a garden house nozzle up the tube from below to try to clear it?

[topgun2]

2 hours ago, Steph and Dud B said:

As a quick fix onsite, can I simply direct a jet of water from a garden house nozzle up the tube from below to try to clear it?

Given where the condensate comes from when its working properly - if you do the garden hose flush thing you risk spraying water into the interior of your Oliver and/or parts of your A/c that possibly you would not want to get wet.

Bill

[John E Davies]

5 hours ago, Steph and Dud B said:

Our curbside drain line just stopped and the water is draining down the side of the trailer. As a quick fix onsite, can I simply direct a jet of water from a garden house nozzle up the tube from below to try to clear it?

Wow, no please do not do that. If the blockage is at the tray you could blow the drain hose right off the nipple. And possibly flood the cabin and electrical items. I would use compressed air regulated to say 30 psi or else mechanical methods. How about a small electrical wire fish tape, or a single wire from residential Romex 14/2 cable? ? Hull 218 has the drain exit at the street side rear corner, is yours different?

If you decide to use the garden hose method, for God’s sake attach an adjustable regulator!. Some sources may be over 100 psi. And video the process so we can all see…. 😉 

John Davies

Spokane WA

[Steph and Dud B]

Think I'll just let it run over the side until I get home.

[mossemi]

56 minutes ago, Steph and Dud B said:

Think I'll just let it run over the side until I get home.

You can adjust the trailer stabilizers and run the water off the roof in the most desirable direction until you determine the problem and fix.

Mossey