how to seal leaky vent pipe in direct vent fireplace?

[natgastech]

Korben know what I'm talkin about. The air comes in because the building envelope was comprimised and not sealed (usually at the wall flashing). I understand Toadie thinks the air is at the connection between the vent pipe and unit and it could very well be both. If the installer didn't seal the vent he certainly didn't seal the wall flashing. And I'm not talking at the term cap thats easy to seal. The problem is on a dv fp when you slide the vent (attached to the fp) thru the wall flashing, How do you seal the wall flashing? Installers aren't doing it. Korben are you? If it is spring, summer or fall who cares? Nobody cares till it's the middle of winter and a draft flows thru. The customer points to the Buider, the buider points to the installer, the installer points to the drywaller, and the drywaller points to the insulator points back to the installer...and so on. The answer is it is the buiders responsibility to line up the trades so the wall is intact before the install. Then the installer can do his job (assuming he is equiped). In Toadies case he was screwd cause the installing company didn't do it properly and they should have to fix it. In Canada we he Technical Standards Saftey Authority that I would call in a second if I found a vent not sealed like Toadies.

[korben]

Living in Canada I seal every hole to the outside. Sealing around the vent may be messy but it is hidden so no one will ever see my hack caulking job and since I can not see parts of it I use a little more.The guys that trained and showed me stressed the importance of sealing it all up. I always know when it is going to be a hard one when I get told to do it.

[jtp10181]

If the builder doesn't have the wall in tact (insulation / drywall / draftstop) we do it for them and charge them for it. They all know this and accept it.

If there is a cold air problem later and it is determined to be the fault of the install, that installer knows he will be fixing it without being paid any additional money.

[korben]

hmm do not normally have insulation or drywall in my truck.

[natgastech]

exactly

[SeattlePioneer]

Good explanation of the problem as always, natgastech.


What I love is when you find these air leaks on the side of a ten story condo!

Or a contractor on such a building who screwed around with the termination cap, so you have a building full or fireplaces that don't vent.


I imagine it is VERY expensive to put scaffolding up ten stories so you can repair such defects!


When I find something like that, I worry that contractors will put out a contract on my life, figuring that Dead Men Tell No Tales That Will Get Contractors Into Trouble!



Seattle Pioneer

[DarthDaver]

I realize this is an old post, but a google search brought me here. natgastech is most likely right on this one. I can't tell you how many times I have removed a sidewall termination and caulked up the 3/8" gap between the DV termination pipe and the firestop with RTV using a cauling gun and 12 or 18" of 3/8' plastic tubing because some installer didn't know or didn't care.

That said, it's so much easier to do things right the first time, guys!

[Wester399]

Use some fiberglass batt..r20 or so because you cannot use the expanding foam for obv fire reasons.Just stuff it in the hole behind the plate that your exhaust pipe runs out.

[hearthman]

Wester, you cannot pack insulation or anything else into stated clearances. That wall firestop assembly was tested with an air space. You pack it and you can burn a house down. I've investigated enough of them to know.

[Wester399]

Sorry i didnt read the post 100 percent on the last install I did there was a 26ga steel box the venting went through before termination outside and we packed some extra space between that and the stud wall with insulation. Sounds like everyone here has suggested high temp silicone to seal it up.

[hearthman]

You have to read the mfrs listed instructions. Some of these firestops cannot be caulked on the inside and must breathe. Sealing and packing these firestops can be a fire hazard. Each model's instructions is the code.

HTH