Solid chimney liner install questions

[GlacierBay12]

After getting the smoke box clean, I am trying to anticipate any install issues. I believe I have settled on the Saf-T vent solid liner with insulation as the chimney is pretty much a straight drop with a 7" shift in the smoke box. I think I have enough room that 2 - 15 degree elbow with a 24" section will accomidate the shift.

With the solid liner, how does it handle expansion? Do the pop rivits survive the frequent heating cooling? Is there any noise associated with fastners loosing up and the expansion?

The chimney is an external masonary with two flues, the second being the oil burner. The woodstove flue is current a clay flue which raises 8" above the oil burner flue. Should I keep this flue higher or do I cut it down to the crown? When installing the top plate, the instructions say to secure it with silicone. Is this really sufficient to keep the top plate in position and not open the chimney to the elements? Why not use tapcons and have the ability to remove for maintainance and inspection?

Thanks in advance for any feedback.

 

[weatherguy]

My pellet stove liner top was installed with silicon and its a bear trying to get it off so I can drop a 6" down for my woodstove, Ive read other people securing with tap cons and I probably will this time also.

Dont have any knowledge on your other Q's but someone else will.

 

[CarbonNeutral]

I would presume that the rivets will be fine. I also supported mine from the bottom though, just in case

 

[jbrown56]

Glacier,

My install was easy because it was a 20' straight shot into a tee. The liner extends three feet above the cap. Better draft. The clamp that holds the liner in place sits on the cap and is siliconed in place. It's been three years and seems to work fine. It cleans easily. Seems much more durable than flex.

With the rigid, I don't understand how you're gonna make the turn at the bottom. Maybe it would be easier to use flex for the last few feet through the "throat" to the stove.

Jim

 

[CarbonNeutral]

Typically you would use flex to get round the smoke shelf/damper, then into a tee to make the turn.

 

[GlacierBay12]

Thanks for the responses. So it sounds like I should not be concerned with the top plate shifting over time and opening the flue. Still not clear if I am better to cut the clay flue down to the crown; perhaps better bonding to the crown than the 3/4" lip of the clay (?). The chimney is just under 4' off the roof peak with the next nearest roof line 13' and perhaps 2' higher.

The chimney is fairly massive (I'll try to remember to take some pix tonight) and as such has like a 3' smoke box above the damper and below the flue pipe. Using CAD it works having a 15 degree elbow - 24" straight - 15 degree elbow to get the 7" shift to the top outlet of the stove. As for getting through the damper, I was able to cut away a sufficient opening. It was my thought that although flex is good, rigid was better. That and I had read that cleaning rigid is easier. But all the rigid got me to thinking about the expansion. With a small length of flex, the rigid up top probably does not raise up at the top like it would with rigid.

 

[oconnor]

The rivets are stainless steel - at least they should be - so no trouble there. If you have the ability to attach the bottom sections and secure them as per instructions, then rigid liner should be fine. As for the top, mine is siliconed down as well - no need to look at the outside of the liner so long as the inside is in good repair. If you need to remove it, then cut the silicon with a sharp knife - you will end up replacing the flashing anyways.

Follow the rules for adjoining flues when it comes to the wood side - keep it higher than the oil side. You can end up with the oil side drawing smoke down to the furnace room otherwise, better it be just cold air instead of smoke. I don't recall the specific measurements - someone here will have them.