A/C condensate running off the roof... NOT out of the drain tube

[jmpgino]

OK I am sticking in my ten penneth in again as when I lived in England we used to say.
I did not like the connection CLIPS that Dometic supplied with the hose and cup kit. I bought some real compression clips that you screw down to tighten the seal in the pipe onto the connector. They just did not seem strong enough to create a permanent seal on the condensate lines, but I still had to be careful not to obertighten them because it was plastic on pvc. It is possible that you have an issue there.
But this aluminium thing you mention does not make any sense to me. The air blows down from the fan through a flexible pipe, this allows the air not to be contaminated with the return air that is going back into the AC to be re cooled in the box.
So you may have a loose connection there, just a thought.
Today when I went back on the roof while the unit was running, I noticed a drip drip ddrip constantly leaking from the unit onto the roof that was a good seven inches behind the drain cups. I just can not be bothered at the moment to look into it, the heat during the day here at the moment is vicious.
I said earlier that this was going to be a serious topic in the future and some other chap has agreed.
It makes you wonder if the unit should just be allowed to drip on the roof and evaporate away as it most likely would down here in the south......

[jmpgino]

Trying to upload an image here.

[RFP]

Originally Posted by jmpgino

I did not like the connection CLIPS that Dometic supplied with the hose and cup kit. I bought some real compression clips that you screw down to tighten the seal in the pipe onto the connector. They just did not seem strong enough to create a permanent seal on the condensate lines... < snip >.

Remember, James, there is zero pressure on this drain system... should never leak from the hose/plastic interface unless one or the other is damaged.

[jmpgino]

Robert, if you can why not post the images I sent you on here, to share with the other chaps.
I did a web search and tried their instructions on posting an image with the new iPad I just got and it was a complete failure.
Cheers,
James.

[jmpgino]

Looks like I have done it. Was able to use this site and upload them on that.

I have added some images that show insulation I have added for the ceiling fans and skylight. I can assure you that adding a few layers of this stuff, has enabled me to get the inside like a meat locker. Those three boxes really let the heat inside. Even the shower and bathroom vents let heat in, so I have done them as well.

Click on this link.....


https://www.flickr.com/cameraroll/

[ShinyPete]

I know this thread took a very technical turn addressing some specific issues, but I just wanted to thank the earlier posters for the basic troubleshooting info on this thread for the Dometic drain system on modern day Airstreams. We are on day 3 of a 4 day trip to Ft Desoto park in St Pete Fl when I noticed condensate draining off the roof near the door of our Pete, a 2014 27fb. Jumped on AF, read this thread, took off the internal shroud, cleaned the goo out of the drain line T, and bingo, major condensate drain line flow again.

That’s why I love AirForums. Hunt a little, and you can find SO many solutions to our collective Airstream ongoing maintenance requirements.

Thanks all!

[RFP]

Originally Posted by ShinyPete

Jumped on AF, read this thread, took off the internal shroud, cleaned the goo out of the drain line T, and bingo, major condensate drain line flow again.

I love a happy ending!

[A W Warn]

Originally Posted by PJohnson

There should be a plastic cup on each side the air conditioner. The cups collect the condensate and are drained by the tube. If the cups are in contact with the roof, they can crack and allow the condensate to run out onto the roof. Replacing the cups requires removing the air conditioner. This is a job for Airstream service. Make sure they have the proper gasket for a re-install. IT IS A SPECIAL GASKET. If your local service dealer try’s to jury rig the install, you will have nothing but problems. I know, I had to take my Airstream back to Jackson Center after my local Airstream dealer tried to juryrig the re-install.

It is not a special gasket. It is a standard 14" x 14" gasket that has to be modified by the installer. The gasket comes as part of the drain cup kit. This is clearly explained in Dometic's instructions.

Originally Posted by Gene

Posters are talking about different A/C's and different trailer models. Please specify what you are advising about because installations are different.

Gene

I've installed 3 different Dometic rooftop units. The drain cups are installed the same way on all three, except on the Brisk Air unit the factory provided screw holes were off a bit where the others fit the cups perfectly.

Even though those that I installed used air distribution boxes, not interior ducted, I cannot see how this difference would change any part of the drain cup install.

I did notice that some mention of the drain pan (the old way). That is a different method of capturing the condensate. I assume some people are not aware of the two different methods. Based on my limited experience, I think any Dometic unit will fit the Airstream drain pan and/or accept the Dometic drain cups.

[GammaDog]

It's me again. About AC issues... again.

I bit the bullet and installed new drain cups and gaskets (note the trailing "s" on that second word).

First off, thanks to all of you who posted ideas earlier in this thread. Without your inspiration I would never have attempted this. Now that the work is done I wish I had done it three years ago.

This may take a while. I'm hoping to leave a trail of breadcrumbs for other unfortunate campers to follow. I also look forward to these creative writing exercises... it's cathartic for me.

After reading your stories I told my wife over coffee one morning that I think I need to pull the AC off the roof to fix the constant drip, drip, drip. She said "Like hell! You're not dealing with ladders and electric issues on the trailer. You'll fall and break your neck... or worse. Don't do it!". So, after she left for her volunteer job at Hospice I headed to the trailer with my tools, ladder and the gasket kit I had already purchased. I thought the odds were low that I would need her services that day, but it was comforting to know she was standing by to make the handoff just in case Wally Byam called me home.

Like most projects AS-related or otherwise, I took this one on solo. As many of you observed above, having helpers is advisable. I just don't have any. A large supply of moving blankets is essential for any of you who want to try this solo.

In addition to the condensate running across the roof I have had an issue with condensate dripping inside the trailer on occasion since the trailer was new, or nearly new. This is a symptom covered in other threads, but I didn't connect the two until I dismantled the unit today. More on that later.

Before working on the unit I turned the AC 120v breaker off and pulled the fuse for the circuit that the thermostat is on.

I first removed the grille and the three long bolts that secure the roof unit to the ceiling plate. I removed and set aside the plate.

I started undoing the wiring at splices, joints and connections where trailer wire meets Dometic wire. LABEL THESE CONNECTIONS CAREFULLY since some are very similar (e.g.: the Dometic wire harness includes two, blue 16 or 18 ga wires. One joins to an identical wire on the trailer side. The other joins a blue wire with a white stripe. Only careful tagging before removal will get these joined up correctly later.)

Unpleasant Surprise #1: When I opened the single gang box in which Airstream joined the trailer's 120 v system to the Penguin II it was wet inside. This wasn't condensation on the surfaces in the box. It was clearly AC condensate that has been blown into the box through any of the many holes in that type of box. There was simply too much water in the box to have condensed directly on the components inside a covered box. This was a clue that would fit together with others later.

Unpleasant Surprise # 2: Although I had removed the grille a half dozen times over the years to clean the drain lines, I had never removed the ceiling plate. Doing so allowed me to see for the first time the point at which the drain line exits the 14x14" opening through the roof and heads into the ceiling on its way to the sidewall and eventually the streetside wheel well where it dumps the condensate. The tube was kinked in the hole where it went through the grommet in the aluminum frame. It wasn't pinched off completely, just seriously constricted. The cause was clear: There wasn't enough tubing extending into the trailer to reach the tee fitting in the line between the two drain cups. The drain tube was pulled to fit anyway. The kink appeared where the now taut drain tube turned the bend and passed through the grommet.

Unpleasant Surprise #3: When I removed the ceiling plate, the very short piece of duct that connects the bottom of the blower housing in the rooftop unit with the grille fell out. That prompted me to explore how to replace it when the time came later. After some inspection it was clear that the upper plate of the assembly had been secured to the bottom of the blower housing with mounting tape. That tape was still affixed to the plate on the upper end of the duct, but the side that was intended to stick to the blower was dirty and stickless. My conclusion was that the duct had not been doing its job for a long time... maybe never.

I moved to the roof. I piled three folded moving blankets between the rooftop unit and the awning. I rolled the roof unit 90 degrees onto its side on the pile of blankets. I confirmed what you followers of this thread already knew. I had only one gasket (not the two Dometic specifies). The drain cups had been sitting directly on the roof and the drain tubes had been pinched between the roof and the bottom of the roof unit as the three bolts were tightened. Neither drain cup appeared cracked or broken.

Reassembly:

I had purchased the Dometic drain kit (which comes with one 14x14" gasket) and a second gasket. That lone gasket turned out to be a Camco product and seemed to be a significantly different foam. The existing gasket on my unit was in good shape. I decided to leave the existing gasket in place and use the new Dometic gasket as the second gasket. I cut the existing gasket with a utility knife in both places where the tubing passed between the drain cups. I removed the old cups and secured the replacements and their tubing in place. I used parbond sealant (ask me in two years if that was a good choice!) to seal the cuts in the gasket. I removed the protective strips and affixed the new gasket on top of the old. I added the two straight gasket sections to the aft end of the roof unit. I was done topside. I rolled the unit back in place but did not attempt final positioning from the roof. (Note: I considered leaving all wiring connections in place and cutting the new gasket to fit around them then sealing the joint with parbond. That would probably work but I was concerned that a break in the gasket could create a point for water infiltration. If you choose that approach I would recommend the cut on the aft side of the gasket. The front takes the wind load and wind driven rain while underway and the sides already have cuts through the upper gasket for the tubing from the drain cups. Using the cut-gasket method would probably save 60-90 minutes given the disconnection and reconnection of wiring that it would avoid.)

Back inside I positioned the unit by lifting it, moving and lowering. It's light enough and balanced well enough to do this for fine adjustment. I removed the old 120v single gang box. I replaced it with a single gang suitable for wet locations. That included a gasketed entry point for each cable and a gasketed cover. I took extra care joining the hot and neutral legs. The trailer wire is 14 ga solid copper. The Dometic wiring is 12 ga stranded. There are techniques to joining these mismatched wires properly. It looked like the factory joints which I cut out were not sound. The wire nuts appeared to have gripped the solid conductor and pushed the stranded down toward the insulated section. I think I got better connections by starting the wire nuts on the stranded then introducing the solid conductor and finishing the tightening on both together.

Given the wiring issues and presence of water I twisted and soldered all 12 v connections (which are in the open and not boxed) then capped them (small wire nuts for the two large ones, crimp caps for the two small pairs) and taped them all with rubber electrician's tape to improve water resistance.

I secured the upper duct plate to the blower housing with 3M extra hold mounting tape.

To fix the drain kink I wanted a 1/2" x 1/2" nylon barbed elbow. Home Depot didn't have one, so I ordered one from Amazon. I'll have it just in case and would install it where the tubing bends through the grommet (don't cut it too short and lose the end into the wall cavity!). Instead, I got a 1/2" x 1/2" barbed brass straight connector and used it to add about 2" of tubing between the tee and the too-short drain line.

With everything reconnected I replaced the ceiling plate, tightened to spec using an inch-pounds torque wrench and replaced the lower retaining plate for the duct. The grille went back on and voila! AC!

Elapsed time about 3 hours not counting a trip to Home Depot which included buying lunch for my wife and telling her she was totally right... I should have listened to her and never, never attempted a job like this myself. Next time I'll be smarter and take her advice.

I concluded that the biggest issues I had were not the gasket or the cups. Those things were not right, but for me they were not catastrophic either. The bigger issues were the kink which didn't block the flow of condensate but probably slowed it enough to back water into the cups during heavy AC use in high humidity (that describes life here in Florida for about 8 months of the year). That slow flow would account for why I would sometimes have drainage from both the wheelwell and across the roof. The other issue was the gap where the duct wasn't sealed to the blower housing. That caused a large part of the blower output to pass directly back toward and through the (very wet) fins of the evaporator coil. That was confirmed when I pulled the cover off the roof unit, removed the foam insulation and the upper housing to inspect and clean the evaporator section. The drains from the pan into both cups were pristine and the geometry and proximity of the blower exit and evaporator made it clear that any air that didn't make it out the duct below the blower was going to spray condensate all over the inside of the evaporator housing. That probably accounts for the dripping inside the trailer and the water penetration into the 120v box.

So, that's my story. If you actually read all of that I think you might do better with a prescription for Ambien, or it's time to pull your AC apart. Go ahead, you can do it! Just make sure your spouse is understanding of the effects of your bad case of "it-ain't-right-and-I'm-gonna-fix-it-itis". Mine is.

I took pics of many of these steps including the top unit with all of its insulation and covers removed. If you got this far and need more detail just add a post here or PM me and I'm happy to share if it helps someone else.

Happy 'streamin!

[GMFL]

GammaDog,
Great post!

[RFP]

Originally Posted by GammaDog

It's me again. About AC issues... again.

I bit the bullet and installed new drain cups and gaskets (note the trailing "s" on that second word).

< anip >

I took pics of many of these steps including the top unit with all of its insulation and covers removed. If you got this far and need more detail just add a post here or PM me and I'm happy to share if it helps someone else.

Happy 'streamin!

Wow, 'Dog... what an excellent write-up! Please add your photos, you are really adding to the brain trust here!

Originally Posted by GMFL

GammaDog,
Great post!

Yes, indeed!

[RFP]

Originally Posted by GammaDog

< snip >
Unpleasant Surprise #1: When I opened the single gang box in which Airstream joined the trailer's 120 v system to the Penguin II it was wet inside. This wasn't condensation on the surfaces in the box. It was clearly AC condensate that has been blown into the box through any of the many holes in that type of box. There was simply too much water in the box to have condensed directly on the components inside a covered box. This was a clue that would fit together with others later.
< snip >

GammaDog, this is really troubling (maybe it shouldn't be, but I'm a worrier). I'm still thinking about your theory that the cause was condensate water being blown around. After having my A/C installed correctly (as you did yours), I found that after a couple of hours operation, the condensate ran freely from the drain in the wheel opening, BUT there was also a little bit of water on the roof right up against the gasket that's toward the back of the A/C. It was clear that this water did not come from the drip cups.

So, back up on the roof I went. I turned the A/C off and took off the shroud expecting to find sweating suction-side copper tubing. Nope, that stuff, while predictably "cool," was Sahara dry.

But, I did see that parts of the fan housing were cold and sweating. Apparently, this "sweating" was working its way down onto the roof. Now, I'm talking about only a very small amount of water, but after fiddling with this for a while, I'm super-sensitive about ANY roof water.

I should also say that during all this fracas, I had left off the plastic inside grille, and I could see that no water was working its way into the inside of the trailer.

Maybe I need to get a hobby, and quit worrying about such stuff.

[RFP]

Originally Posted by patty413

I have condensation dripping inside of my airstream when Ac is on. I called a local Airstream service department and he suggested checking the “flap” that separates the hot and cold area of the ac to see if it’s loose. He said it looks like aluminum foil. Anyone ever hear of this and is it something we could fix easily. He said to remove the cover to check it?

Patty413... I see that you haven't been back to the Forum since just a [very] few minutes after you posted about your condensate drip. I'm wondering what, if anything, you discovered and if you solved the problem. Please let us know.

[RFP]

Originally Posted by patty413

I have condensation dripping inside of my airstream when Ac is on. I called a local Airstream service department and he suggested checking the “flap” that separates the hot and cold area of the ac to see if it’s loose. He said it looks like aluminum foil. Anyone ever hear of this and is it something we could fix easily. He said to remove the cover to check it?

Patty413... I see that you haven't been back to the Forum since just a [very] few minutes after you posted about your condensate drip (25 days ago). I'm wondering what, if anything, you discovered and if you solved the problem. Please let us know.

[GMFL]

Rob,
On my new unit after running it for a while I notice a small amount of condensation on the roof around the gasket. After examining the moisture I determined it to be the metal sweating due to the extreme temperature difference of the roof metal around the gasket.

Also when I removed my old AC the handy box that has the 120 volt wires showed signs of being wet. When I reinstalled I used silicon greased wire nuts to protect against water intrusion.

[RFP]

Ronnie, my little bit of water on the roof was definitely coming from the A/C unit. I could see that there was a little 'droplet' hanging from the bottom of the A/C.

My 120-volt connections were dry as was the handy box. Is your electrical box just pushed up into the return air cavity? Mine was; now it rests on the ceiling plate just behind where the condensate drain tubing runs.

Yikes, what am I doing up so late? Nighty nite all

[GMFL]

Yep, handy box just hanging out in the return air hole.

[A W Warn]

Originally Posted by GammaDog

<<snip>>
So, that's my story. If you actually read all of that I think you might do better with a prescription for Ambien, or it's time to pull your AC apart. Go ahead, you can do it! Just make sure your spouse is understanding of the effects of your bad case of "it-ain't-right-and-I'm-gonna-fix-it-itis". Mine is.
<<snip>>

I read the whole thing! Excellent write up!!
It's almost 1am as I write this. You might be right about the Ambien

[GammaDog]

You people are nuts! That's what I love about you. Family and friends read our tales of the road as I blog about 'streaming around the country. Only you folks will read a 1,000 word essay about air conditioning repair and the challenge of balancing the perils of roof work with marital harmony past the age of 60. You're the best!

A couple of thoughts:

RFP: There are lots of places in the roof unit where the insulation is thin or where the plastic housing on the cold side continues uninterrupted to the outside. In high heat/high humidity conditions there will be condensation there. I see signs of rust in places in my unit that tell me I've had that. I would wager there is enough condensation there on 90/90+ days to have some drip to the roof. The base pan of the roof unit has drains to allow water to escape if it enters from driving rain, so some water shouldn't be a problem or a surprise. Next week I will move the trailer from my son's house to our house (thanks to a pothole on I25 in Denver on the way from Colorado Springs to Estes Park I have a fresh water leak and need to drop the tank to find it. Our driveway is made of pavers, his parking pad is gravel, guess where I want to pull the tank?). I also have to touch up roof caulking. Now that my AC is running again I'll pull the cover and see what I have there and let you know. (Addendum: After writing the rest of this and looking at my pics from yesterday I believe the cold section of the roof unit is uninsulated on its underside. I'll confirm that later this week. The only insulation appears to be the styrofoam cooler material that's been molded around the top. If that's true, this beast is going to sweat like a witness in a Congressional hearing. The condensation that forms on the underside of the plastic evaporator housing will drip into the metal base pan of the roof unit, through its weep holes and onto the roof.)

Let's try some pics. Remember, this is a 2014 Airstream which means our system is unducted. The Eddie Bauer 25 in that year shipped with a single Dometic Penguin II 15,000 BTU model with heat pump. If your system is ducted (2015 model year or newer), much of this doesn't apply.

I'll start with the unattached duct. This is a three part assembly. It has an upper plate with a rectangular hole that is to be positioned directly under the blower for the evaporator section of the roof unit. That blower is the circulator fan to move the warmed or cooled air into the grille for circulation in the living space. Return air is drawn through the front f the grille, through the filters, into the roof unit, through the evaporator coil and back into the blower. The blower is about amidships in the roof unit and directly above the aft end of the grille. There are three positioning tabs on the upper plate of my Penguin. These are not locking tabs. They simply align the plate with the sides and one end of the blower housing exhaust opening. Attached to the plate is a 4" or 5" inch long section of clear flexible duct. It is attached to the nozzle of the plate with a ziptie. The lower end of the duct is to be attached to the ceiling plate with an elliptical/rectangular grille about 8"x4" held in place with two screws. This grille friction fits inside the lower end of the duct and is slipped into the opening in the ceiling plate then screwed down at each end. Note to Patty (you're still there, right Patty?). My unit has no aluminum foil baffle. I suspect it never did. This duct is essential to routing the conditioned air into the distribution section of the grille so it can be shot out the bottom vent and the little flap doors on the four sides of the grille.

Here's pic of the upper plate with its useless mounting tape and the ductwork. Note the three positing tabs along the opening. I couldn't afford a professional hand model or commercial photographer but I spent a small fortune for the backdrop:



Here is that part being put in place. This pic was taken with my back to the curbside. To reattach the plate I put 1" wide extra hold 3M mounting tape around the perimeter of the plate directly on top of the now useless factory tape in the pic above:



Let's talk drain tubes, may we? If you've been following this story you already know that the drain system begins with the plastic cups screwed to the underside of the metal base plate of the roof unit. Those cups are connected to each other and to the drain line with clear plastic 1/2" tubing. All connections are secured with spring clips. This is certainly adequate since this system is unpressurized. The line between the cups has a tee fitting offset to the street side to which the drain line is connected.

This pic shows my moment of truth. It was taken with my back to the curb side the clear tube on the right of the pic is the new line between the new drain cups and the tee fitting is visible. The dirty line running right to left is the drain to the street side wheel well. This is when I connected the drain to the tee and realized it put a kink or fold in the drain where it passed through the grommet in the aluminum frame that forms the roof opening.



And here is a similar view showing the brass straight connector with the additional 2" of tubing to the tee. Wait a minute... oh crap... it looks like I forgot one of the spring clips. There should be three in this pic, one on the tee and one on each end of the brass. Oh well, Airstream didn't clip the drain to the tee before shipment (seriously... there was no clip on that line when I first opened the unit after purchase). It'll live until I need to open it again one day. Notice that the drain now has a continuous sweep, not a 90 degree bend with a fold. I would prefer to put a 1/2" x 1/2" barbed elbow at that turn. I have one on the way and may install it since I now know I'm missing a clip up in there anyway.



That's it for now with coverage of what I think were my two main problems. I'll be checking the trailer later today to see if my work held up to 24 hours of Florida summer. I'll try to post the rest of the pics later, especially the disassembly and workings of the topside unit.

Later....

[GMFL]

Again, excellent documentation.