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Birchwood
07-05-2012, 04:19 PM
I sealed the top of my 4 vent pipes with duct seal to curb the entry of sewer gases into my attic.My new front A/C was pulling these gases into the coach.
Will there be a problem with tank and pipe flexing as a result of the pipe
sealing?

jbeletti
07-05-2012, 04:24 PM
What do you mean by "seal"? Did you cap the vent pipes off completely such that they no longer vent at all? If so, I'd venture a guess that it may cause you some issues. When you were up there, did you remove the vent caps and see if the vent pipes had not fallen down into the tanks, rather, that they still extended at least flush with the roof so the gases could escape?

Birchwood
07-05-2012, 05:03 PM
What do you mean by "seal"? Did you cap the vent pipes off completely such that they no longer vent at all? If so, I'd venture a guess that it may cause you some issues. When you were up there, did you remove the vent caps and see if the vent pipes had not fallen down into the tanks, rather, that they still extended at least flush with the roof so the gases could escape?
Jim
All of the pipes extend an inch or two above the roof up into the vent cap.Where the black pipe comes through the roof there
is a gap surrounding the pipe that ranges in size from 1/16 to 1/4 of an inch.I used the duct seal(its a gray coloured putty
that never hardens) to close this gap.My theory is that on occasion(winds and drafts) the sewer smell from one of these
vent pipes enters the attic through these gaps and is drawn through the new A/C into the coach.Since I sealed the gaps the smell
has stopped and we are finally enjoying a cool bedroom.Should I be concerned about sealing around the vent pipes.

cookie
07-05-2012, 05:11 PM
I sealed mine up a long time ago.
No problems.

Peace
Dave

MTPockets
07-05-2012, 06:55 PM
I noticed that gap on mine too.... Should it be sealed? Where does the water go when it rains? I haven't noticed any problems but this thread got me wondering....

cookie
07-05-2012, 07:15 PM
I noticed that gap on mine too.... Should it be sealed? Where does the water go when it rains? I haven't noticed any problems but this thread got me wondering....
There should be vent covers on the vent pipes. Part of that cover would include a flange that the cover can screw into. Rain should never get to enter that area.

Peace
Dave

MTPockets
07-05-2012, 09:06 PM
There should be vent covers on the vent pipes. Part of that cover would include a flange that the cover can screw into. Rain should never get to enter that area.

Peace
Dave

Covers and all is there... What did you seal? and why? was it to prevetn potential leaks/odor intrusion?

cookie
07-05-2012, 09:24 PM
Covers and all is there... What did you seal? and why? was it to prevetn potential leaks/odor intrusion?
I removed the one screw holding the cap on. Then I sealed around the vent pipe.
I did this for odor intrusion. It wasn't from just using the AC, but using the bath vent fan as well.

Peace
Dave

MTPockets
07-05-2012, 09:30 PM
I removed the one screw holding the cap on. Then I sealed around the vent pipe.
I did this for odor intrusion. It wasn't from just using the AC, but using the bath vent fan as well.

Peace
Dave

I'll do it!.... Can't see that it'll do any harm. Thanks

Birchwood
07-06-2012, 05:54 AM
I'll do it!.... Can't see that it'll do any harm. Thanks

Someone suggested that sealing the pipe where it goes through the roof may not be a great idea
because the pipe should be able to flex when travelling and move up and down as the tank is filled
and emptied.If you use a flexible sealer as I did there shouldn't be a problem.I am asking the factory
why its not done during manufacture just to be on the safe side.

rick_debbie_gallant
07-06-2012, 06:43 AM
could the reason be: that gap around the stink pipe is to help ventilate the attic space? If not how would it (the attic space) get ventilated? Inquiring minds needs, well not needs but how about wants to know.

jbeletti
07-06-2012, 07:10 AM
could the reason be: that gap around the stink pipe is to help ventilate the attic space? If not how would it (the attic space) get ventilated? Inquiring minds needs, well not needs but how about wants to know.

Rick,

In coaches that do not have the laminated roof system, there are extra vent caps on the roof that serve to help ventilate the roof. In the case of the laminated roofs, there is nothing to ventilate as they are solid panels with the exception of the voids in them that comprise the AC ductwork.

cookie
07-06-2012, 07:43 AM
Someone suggested that sealing the pipe where it goes through the roof may not be a great idea
because the pipe should be able to flex when travelling and move up and down as the tank is filled
and emptied.

My thought is that the tanks bulge out on the bottom as they are filled, not the top. And the tanks don't move when traveling.
Just my thought.

Peace
Dave

danemayer
07-06-2012, 08:17 AM
My thought is that the tanks bulge out on the bottom as they are filled, not the top. And the tanks don't move when traveling.
Just my thought.

Peace
Dave
Dave, you might be right. On the other hand, if there is even a little vertical motion of the tank, anchoring the vent pipe at the other end might produce some undesired stress where the pipe attaches to the tank.

I wonder if maybe it's just gravity keeping the tank from moving up when you hit a bump in the road. Judging from how things inside the RV get bounced around, I wouldn't be surprised if there was some small amount of tank bounce as well.

rick_debbie_gallant
07-06-2012, 08:32 AM
Rick,

In coaches that do not have the laminated roof system, there are extra vent caps on the roof that serve to help ventilate the roof. In the case of the laminated roofs, there is nothing to ventilate as they are solid panels with the exception of the voids in them that comprise the AC ductwork.

IOW, that space should be sealed up? Now I am confussed? "To seal or not to seal", that is the question of the day.

hoefler
07-07-2012, 07:15 AM
Liquid sloshing around would cause the top of the tank move up and down. Also, as you over fill the tank, up into the drain lines and the vent stack, it will also cause the tank to swell all around.

KWire
07-07-2012, 05:38 PM
Hi all,

Is Heartland using ABS pipe for the vent? If so you might also want to keep in mind that a 10 foot piece of ABS pipe will expand/contract about 1/4" for a 40 degree temperature change. So if you fasten it solid at the roof with sealant or caulking where does that expansion go when the temperature changes? Does it push up on the roof now when it expands? Does pull on the pipe when it contacts?

I owned a couple of trailers back in the 70's and they had the same gap between the pipe and roof. I always thought the space was to accommodate this expansion.

Just another idea...

Keith

Birchwood
07-14-2012, 05:17 PM
I sealed the gaps around the 4 sewer pipe vents on my Pinehurst.There is one mushroom vent that I assume is used
for attic venting.Heartland (I think) implied the gap around the sewer vents also acts as attic vents.My question is
will the one mushroom vent do the job?

Rodbuster
12-15-2012, 05:34 AM
I was up on the roof of my Landmark yesterday and noticed that there are 3 of these vents (I think they call them mushroom vents) in a straight line. All 3 were together and took up about 12 to 15 inches. The middle vent cap was missing.

Would anybody know the exact name and/or part number for this piece?

Thank you
Dick

boatto5er
12-15-2012, 07:50 AM
The vent caps are fairly generic. You can get them at Camping World or online from Tweety's and other sources. Several people have replaced their generic covers with Venturi type caps that rotate with the wind direction. You probably need to know the diameter of the vent pipe when getting the replacement cover.


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tboy
11-27-2013, 01:37 PM
On my 2013 Key Largo I had the same problem with sewer gas when I had any of the roof vent fans on exhausting out. When I checked all the sewer vents I found the one for the washer that was going out of the roof had a large gap around the pipe were it went through the roof, I sealed around the pipe and roof and never had the problem again. The roof vent fans would suck the gas back into the coach through the gap in the roof around the pvc. It only did it when all the windows were closed and the air conditioning was on, here in Florida the air is on most of the time.