Electrical gremlins and plumbing stacks...

[dbailey]

A month or so ago we were on the road with our 19 when a pretty significant rain storm came through. A lot of rain pounding down hard, and we were driving through it. For the next couple of days we had a variety of different electrical problems -- inconsistent furnace function, battery drawing down way too quickly for the load we had on it, outside light working erratically, etc... Obvious conclusion was that we had water inside. Sure enough, once everything had time to dry out, everything worked properly again.

So the hunt for the water infiltration point began... I was suspicious of a few things, but particularly the plumbing vent stack. What I learned investigating this did not make me happy.

It looks like these things are installed in a couple of pieces. Cut a hole in the foot plate for the stack pipe, seal this piece down and caulk the pipe around it. Add the riser part of the vent and seal/caulk it down. The cap on top is then snaps in place.

The problem I found is that the caulk between the vent pipe and that first foot plate was not doing its job. It was a putty of some sort, and it had somehow worked its way up so that it was 1/2" above the foot plate. If I poured water down the outside of the vent pipe, it just disappeared somewhere inside the trailer. I cut a hole in the plywood wall beside the dinette and I could see the water running down the vent pipe.

The *real* problem is that there is no way to fix this caulk joint! There's no way to get a finger, or a tool, or the end of a caulk gun down between the vent riser and the stack pipe. Looks like the only option is to completely remove the vent cover and start over again.

These plumbing vents are a real bad design...

I guess you typically won't get water under the vent cap, since you'd have to have water flowing up hill, but it's not like we ever pull these things at highway speeds through the rain, is it?

I looked at the vent over the sink on the passenger side and while it wasn't nearly as bad, any water poured in beside the vent pipe did slowly leak into the trailer. At least there's no significant electrical hiding downstream from this vent.

At this point it looks like the only real solution is to completely tear off and replace both vents...

Has anybody else seen problems with water infiltration around the plumbing vents?

Thanks for any insight...

 

[Jubal]

Pictures ?

 

[Patandlinda]

Pictures ?

Also would be very interested in some pictures . Thankyou . Pat

 

[PGDriver]

Admitted the vent cap system is poorly engineered and as I believe there is no expansion joint in the vent stack it would be not be advisable to attach the stack to the roof rigidly, the joint or caulking must be flexible to allow for expansion and also flex of the roof. Most RV manufacturers use them and unfortunately they are industry standard.
What I have done in the past is with the cap removed swab the inside lightly with acetone then pump enough liquid butyl to seal the cap to the stack to the roof. This has always worked long term for me.


Cheers
Doug

 

[padlin]

How about using the Cyclone if it fits, you can drive as fast as you want and not get rain in it.

 

[wetzk]

padlin, I wonder what a tree branch would do to it? It looks like it would rip the pipe out if one hooked into that wind vane part.

 

[cpaharley2008]

I would insert a smaller diameter piece of hose, maybe 1.5" black drain hose down inside to where the joint is and secure it under the cap and replace the cap. Any water should go down the inner hose past the joint.

 

[dbailey]

I'm not sure I can get a picture that shows the problem, but I will do what I can tomorrow evening.

Doug, I think liquid butyl might do the trick -- I didn't know such a thing existed.

One of the problems with the existing stack is that there is some play in the ABS vent pipe. As it moves, it messes up the caulk. I suspect that's how the original caulk got ruined. But if I completely filled the well with liquid butyl, that should hold the ABS from moving. I just hope that the liquid butyl sticks to the vent well enough that the movement of the ABS doesn't break the seal.

(I also suspect that this problem exists in most Escape trailers, but that it hasn't been noticed because it's rare that enough water gets in to cause problems.)

The existing well is rather dirty, so getting it clean enough for anything to stick will be a challenge...

 

[padlin]

padlin, I wonder what a tree branch would do to it? It looks like it would rip the pipe out if one hooked into that wind vane part.

I think the idea is to not hit trees.

 

[dbailey]

I would insert a smaller diameter piece of hose, maybe 1.5" black drain hose down inside to where the joint is and secure it under the cap and replace the cap. Any water should go down the inner hose past the joint.

Jim, I'm not sure what you're suggesting. I'll try some ascii art to explain the situation...

                 |-----------------------|  cap
                 |                       |
                 |  |     |     |     |  |
                    |     |     |     | 
                    |    X|     |X    | <- vent wall
  roof  ------------|---- |     | ----|--------------  
                          |     |
                          |     |
                          |     |ABS

The 'X' marks the location of the caulk that has failed. Without that caulk, water can run down the outside of the ABS pipe into the trailer instead of down the inside into the tank...

 

[Patandlinda]

Jim, I'm not sure what you're suggesting. I'll try some ascii art to explain the situation...

                 |-----------------------|  cap
                 |                       |
                 |  |     |     |     |  |
                    |     |     |     | 
                    |    X|     |X    | <- vent wall
  roof  ------------|---- |     | ----|--------------  
                          |     |
                          |     |
                          |     |ABS

The 'X' marks the location of the caulk that has failed. Without that caulk, water can run down the outside of the ABS pipe into the trailer instead of down the inside into the tank...

I wonder when we are washing the roof of the trailer ,using a sprayer , is water getting in the trailer ? Pat

 

[cpaharley2008]

I understand now, I thought the joint was within the pipe going down inside, so my suggestion is now void. Sorry about that. But seems to me if you remove the cap, a good flexible sealant should allow movement without an opening and since it is not visible, just fill the entire space between the pipe and vent wall to insure coverage.

 

[AKCamper]

I understand now, I thought the joint was within the pipe going down inside, so my suggestion is now void. Sorry about that. But seems to me if you remove the cap, a good flexible sealant should allow movement without an opening and since it is not visible, just fill the entire space between the pipe and vent wall to insure coverage.

I wonder if it would be a good idea to drill a small hole into the vent pipe to allow water that accumulates to drain down after applying the flood coat of sealant as you suggest?

 

[cpaharley2008]

That may work, like me drilling a small hole in the bottom of my marker lights to dissipate condensation. Or you can wait and see if evaporation takes care of any water intrusion.

 

[padlin]

Could you make an extension for the tube of caulk, something like a piece of rubber tubing?

 

[dbailey]

I understand now, I thought the joint was within the pipe going down inside, so my suggestion is now void. Sorry about that. But seems to me if you remove the cap, a good flexible sealant should allow movement without an opening and since it is not visible, just fill the entire space between the pipe and vent wall to insure coverage.

That's my current thought. There isn't room to get a finger in there to form a putty, but something that I can manipulate with a small stick or chopstick would do the job. That's why I was interested in the notion of "liquid butyl" that Doug mentioned. I haven't looked around to see if I can find it locally, but now that I understand the problem I'm not in such a hurry.

 

[dbailey]

I wonder when we are washing the roof of the trailer ,using a sprayer , is water getting in the trailer ? Pat

I suspect so...

If you want to test, pull the cap off (rotate it 1/8 turn to release) and use a jug to pour a little water between the vent wall and the ABS pipe. If the water doesn't pool there, it must be leaking into the trailer.

I didn't get home in time to get photos before dark tonight, and I'm out tomorrow evening, but I'll try to do that some time this week.

 

[Patandlinda]

I suspect so...

If you want to test, pull the cap off (rotate it 1/8 turn to release) and use a jug to pour a little water between the vent wall and the ABS pipe. If the water doesn't pool there, it must be leaking into the trailer.

I didn't get home in time to get photos before dark tonight, and I'm out tomorrow evening, but I'll try to do that some time this week.

Doug still interested in your photo's . Confused exactly where . Don't understand why it couldn't be caulked . Will need to take a look but I see I think it is diclor around Vent. Sorry for my confusion . Pat

 

[dbailey]

Doug still interested in your photo's . Confused exactly where . Don't understand why it couldn't be caulked . Will need to take a look but I see I think it is diclor around Vent. Sorry for my confusion . Pat

The reason I can't use normal the caulking is simply that there isn't enough room. The place that needs caulk is 3 or 4 inches down in the gap between the ABS pipe and the side of the vent. And that gap is not wide enough to see what you're doing or to work the angle of the caulk gun correctly. Putty doesn't work because I can't get my finger in the gap to shape the putty.

Something thin enough to self-level and fill the whole space sounds like the right solution. If I can't find something liquid, I will try a large volume of normal caulk and use a stick or something similar to spread it around.

 

[gbaglo]

I don't get it. If this vent is so common in the RV industry, there must be an easier solution.