How do I clean my AC drain tube?

[cwf]

When the line stops, cut it off a few inches back and chuck in a drill. Then turn the line slowly. It might dig through. Or run a electric pull tape because it is stiffer than the line.

Using compressed air may dislodge the plug. Also a wet dry shopvac might help pull it out.

[Silver Goose]

Originally Posted by KJRitchie

...
There is no inside access to the drain pan. The drain pan is narrow and deep and looks like an oil sump pan. The gray glob is the drain tube The drain pan is behind the evaporator coil or downstream at the air flow where the condensation collects. I think the only way to check the drain pan is go on the toof and remove the outside AC covers.
...

This discussion has piqued my curiosity. I also suspect that some insect finds its way up the drain tube seeking a source of water and builds something that clogs the line. I'm surprised the A/C drain line doesn't have a perforated cap like the one used on the end of the fridge drain line.

I've peered into the area described and spotted where the clear plastic tubing comes out between the ceiling and roof panels on the streetside of the A/C opening and attaches to the black plastic collection pan that spans the area below the evaporator coil. The grey goop appears to seal and secure the tubing to the pan. I'm not sure you can gain access to the pan from above without lifting the A/C off the roof.

I think the best way to clear any obstruction in the line would be to disconnect the line from the pan and attack if from top down as Pilious suggests but reattaching and sealing the connection may have its own challenges as at least on our models, it is a tight area to work in.. The shop vac and weed wackier line auger from below may be a good Plan B. I would look for the plastic trimmer line that has 3 or 4 edges to it and use a drill on slow. A helper inside with a good flashlight should be able to see when the line comes into the tubing. Once the tip of the line passes the clog, it should be free. I'm going to try to rig up a squeeze bottle with some aquarium tubing to inject a solution of water, some liquid detergent and some bleach into the pan with a loosely attached wet vac drawing it down from the outside. The detergent to loosen any residue in pan and drain tube and the bleach to kill any mold.

I recall that early on there was a fairly steady drip followed by a rush of water when the A/C cycled off. It now seems to drip less but for longer making me think my drain like is starting to plug up and something like this needs to be added to my spring or fall maintenance routine.

[KJRitchie]

I'm using orange .65" multi-sided trim line. I haven't tried the drill yet. When I look at were the exit tube is located, in the wheel wheel forward of the left front tire I notice its position is not in line with the front part of the AC house. Its close to a vertical rivet line so the tubing must run up close to that vertical frame. Opposite the AC is the fridge and its chimney. There is a vertical plate between the AC and chimney, I guess to defect ran or condensation from the AC. So now the tubing has to start running towards the rear of the trailer. Somewhere it has to make a 90 degree turn to come in perpendicular to the the AC center line to insert into the drain pan. Does the drain pan have a male fitting sticking out or does the tube fit inside a hole and that is the reason there is a ton of gray caulking around it.

Another possibility is if Airstream is using clear plastic tubing then it could be kinked somewhere behind the wall. I notice the clear plastic tubing of my fresh water fill vent has a kink in it as it routes from the exterior fitting along the fill tube. It's not a tight kink. What happens if I have that happening inside the wall now I have to have the whole inside torn apart. Be cheaper to get a new AC that discharges the water outside fully. No issues with that design.

Somebody must have had the AC cover off that can tell us if the drip pan is accessible. I would expect the cover to the evaporator to be removable so the evaporator could be cleaned.

This is depressing.

Kelvin

[KJRitchie]

I found this site that shows a drain pan for a Penguin. I'm not sure if this is the one used in the low profile

Drain Pan for Dometic Penguin AC 961270 [961270] - $69.95 : Out-of-Doors Mart!, More Airstream Parts on-line than anyone!

If this design is similar then notice the photos that shows the caulking on the interior and exterior of the drain outlet. That is the best they can do? What sloppy workmanship. I can see why these pans fill up with caulking like that.

I'm also trying to determine from the photos how condensate gets from the flat parts of the pan to the the deep drain tray. There must be some sort of openings. I can see after a few years of use this tray will eventually clog up.

I'm having second thoughts in my purchase of my Airstream.

Kelvin

[Silver Goose]

Kelvin, now that you mention it, there is a good bet there is a section of sheet metal that can be removed to gain access to the evaporator from the topside. How much access this gives to the drain pan is a good question.

From the photo in your link, it looks like this is the pan that was used on my '08 27FB. There must be some holes near the outboard ends of the trough to allow condensation to flow into it. The photo isn't clear enough to determine exactly but it has to work that way. When I return home I'll try to peer into that area with a small camera I have. I sure hope they didn't slop some of that grey goop into the trough and a good flushing will clear things out.

My tubing also somehow angles forward from where it is seen leaving the pan to where it exits on the front end of the wheel well. They have been draining the A/C this way on Airstreams for a long time and I doubt there is a sharp bend or kink in their design, but we all know those things can happen.

Since I know mine was flowing freely as recently as of this time last year, I'm confident it only needs a "roto-rooter" and a flush out.

[KJRitchie]

Went back to my "Silver Mistress" today. I have an air compressor and it set it to 25psi and blew into it. I didn't feel any back pressure so I'm confident the tube is clear. I held the air compressor nossle open with a clamp and then went inside and with the metal plate removed I could hear air coming into the pan. I thought I felt a little air around the hose fitting but a little soapy water didn't reveal anything. Then I took my shop vac and sucked on the tube from the outside for a few minutes. Nothing came out into the dry vac and it didn't seem to labor as when you have the shop vac hose restricted. I went back inside and with the shop vac I vacuumed the evaporator fins. I put the metal plate back on and tighted the nuts tighter than before but noticed the AC tape that lines the output air shaft was collapsing and the plastic cover tabs where the screws go it weren't as flush. It appears only the front 2 channel ends rest on an aluminum rafter, the rear rests on aluminum sheeting. Still they are tighter than they were before.

Here is the AC interior plate photo that the 3 long bolts run through. the center is insulated with a dense foam about 1/8" thick. You can see the water stains on the upper left hand side. That is the street foward end of the plate. Water drips down from the evaporator housing. I'm wondering despite all that gray caulk if there is a leak in the outlet but usually a leak like that leaves a lot of residue and I couldn't see any. Only way to test is wait for a warm humid day and go camping. The left channel had water calcium build up in it, notice how white the left side is compared to the right where no water leaked so I used some sandpaper to clean that off. That would be 5 years of use since I'm the 2nd owner.

The square hole is where the output air comes out. it hits the plastic distribution box and diverts 90 degrees.

Kelvin

[Silver Goose]

Well, I thought I would be able to see something with my inspection camera, but once I got in there I discovered that the condenser is flush over the top of the trough, and that makes sense as you would want all the air flow going through the coil with as little as possible passing around it. With the A/C in position you can't see into the trough. This leads me to believe that there would be little to see from above if you were able to remove the sheet metal that covers the condenser coil.

[KJRitchie]

I have some short lengths of plastic tubing that came from my BakFlip VP tonneau bedcover on my Tundra that I don't need for water drainage and found they were the perfect size to push on the end of the drainage tube in the wheel well. I was able to blow into and suck on the extension tube and felt no obstructions. I also applied some extra caulking around the drain tube this weekend as it appeared the gray stuff wasn't evenly applied.

I'm anxious to test out my AC again now that the weather in Dallas is warming up. Been a cool May so far. We plan to go out this weekend to test all the repairs I've done since our shakedown trip a couple of weeks ago.

Kelvin

[drobert33]

Late addition: things always happen on the road (25’ FC). Didn’t have a shop vac with me (my brother-in-law is still trying to find space for his radial arm saw, but he and my sister have a 40’ motorhome - I think he’ll do it yet). I had to use what I had with me: ream out the tube from the wheel well up with two replacement bicycle brake cables taped end-to-end with really strong tape (thinking of their separating and leaving one stuck half way - I believe I would trade in the trailer and confess at the last minute) and my handy dandy Camco (can’t go wrong there) hand pump for winterizing. After the brake cable proctology I tried to flush the tube with a little benign solution of Protect All mixed into a (collapsible) pail of water and, after a very few strokes on the pump, I was rewarded with rivulets of the mixture flowing down the sides of the trailer, just the thing I was trying to alleviate - I gather that pump moves a lot of fluid with each stroke or that the condensate pan on the air conditioner is not very deep. Flipped the pump hoses the other way around, to suck rather than blow, and was heartened to see the condensate flowing out the tube again. Grabbed an old towel to wipe off the side of the trailer that I had just cleaned (same Protect All concentrate) and waxed (NuFinish) the day before. Now, where to put my table saw ...

[perryg114]

Air compressor from the bottom end.



Perry

[Soyboy]

I look at blowing out the drain with an air compressor as part of my yearly de-winterization process. After it initially got clogged and dumped condensation all over our cork floor (it survived) I made up my mind to do it regularly. For that initial problem, I had to go up on the roof and remove the cover to clean out the drain pan, IIRC some small leaves had gotten in there, covering up the hole, they then in turned retained any dust/dirt that came by. After starting to blow out the pipe every year, I have not had any more problems over the years (knocking wood).

[Bobbo]

This thread may be 15 years old, but it is still VERY useful. My AC stopped draining from the drain tube by the tires, and started dripping from the AC air intake. Using the air compressor set on 20 psi didn't clear it, but getting a long flexible tube and running it as far as possible from both ends did the trick. The tube was too stiff to make the 90 degree curve from vertical to horizontal. (I followed up with 40 psi compressed air just to be sure everything broken loose was blown out.)

[1590Denny]

shop vac at end of tube. use rag or hand to seal the shop vac hose to the ac hose. We do this on our home ac units. Within seconds, the tube will be clear. Don't forget to remove the air filter inside the shop vac.