Sealing Stove Pipe

[velvetfoot]

I'm going to use DVL double wall stove pipe ( http://www.northlineexpress.com/6-inch-dvl-stove-pipe.html ) for a pellet boiler. The pipe is black. Now, I have a feeling that because of the chimney cooling with non-use, there may be transitory positive pressure in the venting when the boiler starts and heats up. Therefore, I'm figuring that sealing the pipe may be necessary.

The tape and the silicone are both ugly. I understand with tape, the sections could be easier to remove than with silicone? I'm thinking I'll use a T off the rear exit to go up, then a T for a draft regulator, and then a T into the chimney pipe; so, hopefully not too much disassembly required.

Does the high temp tape hold up? Could I paint it before application to ameliorate the ugliness factor? Are the tape and silicone equivalent?

Does everyone seal their pipe, or perhaps should I see how it works first?

EDIT: Upon reading the manual, duh, it seems that 45 degree angles and silicone and/or tape is required. So I guesss that answers a couple of questions.

 

[maple1]

I didn't do any sealing on my pipe, can't help much with that - but if you try to put in a cleanout T wherever possible (more than one is OK), and get them in the right places, chances are you will never need to disassemble.

 

[arbutus]

I used the black stove pipe caulk on double wall stove pipe in the past, and couldn't tell it was there unless you were looking right in the joint from three inches away.
Take care during installation and have a roll of clean paper towels on hand to wipe up any excess.

 

[velvetfoot]

I didn't do any sealing on my pipe, can't help much with that - but if you try to put in a cleanout T wherever possible (more than one is OK), and get them in the right places, chances are you will never need to disassemble.

Thanks.
The manual encourages 45 degree elbows. So, I'd have a 45 after the boiler, then a tee for the draft regulator, and a tee going into the bottom of the metal chimney, which couldn't be avoided because of the need to brush the chimney. Would it be possible to take off the draft regulator and stick a brush with a flexible rod in there to clean the stove pipe? The length won't be very long, after all.

 

[velvetfoot]

I used the black stove pipe caulk on double wall stove pipe in the past, and couldn't tell it was there unless you were looking right in the joint from three inches away.
Take care during installation and have a roll of clean paper towels on hand to wipe up any excess.

I didn't realize there was such a thing as black pipe caulk. Is it silicone? The only thing I've seen is red, but I haven't done an exhaustive search.

 

[maple1]

Thanks.
The manual encourages 45 degree elbows. So, I'd have a 45 after the boiler, then a tee for the draft regulator, and a tee going into the bottom of the metal chimney, which couldn't be avoided because of the need to brush the chimney. Would it be possible to take off the draft regulator and stick a brush with a flexible rod in there to clean the stove pipe? The length won't be very long, after all.

I stick a shop vac hose in my barometric damper opening, back & forth one way then back & forth the other. Don't have to take anything off, just prop the damper open & stick it in. Actually, what I really do is stick a short piece of sump pump hose on the end of the vac wand, & run that in. It's really flexible - and you can run it in pretty far if you want to. Just have to be careful you don't tweak the damper flap out of kilter. But you can likely un-tweak it if you do. Not sure how big your damper/regulator opening will be though.

 

[velvetfoot]

I'm not sure either about the damper. I'm going to try to go with a Windhager damper instead of the usual Field Controls. I figure if I only have to remove the baro damper once a year I could live with that. Good idea with the sump pump hose. You don't feel the need to brush as well as vacuum?

 

[maple1]

I'm happy with the job the hose does, on the sections of pipe I can do it with. If I twist it around some & do enough back & forth, I can get at least a scrape on all the surfaces with the hose. But there isn't really much there to start with - just a thin coating of fly ash. I haven't even swept my chimney after two full burning seasons on it - most of my cleaning now, besides brushing the turb tubes every couple weeks, is popping off two clean out covers & scooping/scraping out the ash that has settled there, when I vacuum. I do that in the fall, & halfway thru the winter - but this winter, I didn't do one of them because I think I got the hose in far enough to get most of it out.

I haven't looked up my chimney after winter 2 yet though...

 

[arbutus]

I didn't realize there was such a thing as black pipe caulk. Is it silicone? The only thing I've seen is red, but I haven't done an exhaustive search.

Rutland has black silicone products (as well as clear and red) available.
(broken link removed to https://www.rutland.com/p/4/600f-rtv-high-heat-silicone-sealant)


I used a Rutland stove cement in a caulk gun tube that was listed for metal to metal seals and had a much higher temperature rating.
(broken link removed to https://www.rutland.com/p/10/black-furnace-cement)


I bought it at a Do It Best hardware store.

Like you, I had an elbow and a tee. It was in a wood stove chimney and I didn't have anything in the lower portion of the pipe ever, only the last few feet of the chimney. I never had to take the black pipe apart.

Looks like there is a direct vent sealant available also, and the label says black.
(broken link removed to https://www.rutland.com/p/107/seal-it-right)

 

[bholler]

use mil pac nonadhesive sealant (broken link removed to http://www.igsind.com/mill-pack-black/) I would never use silicone of any kind on pipe joints you are eventually going to want to get them apart. MIl pac is a much better solution