Seal up pellet stove exhaust opening?

[3nickles]

I recently had a Country Pellet stove installed and it's working great. It has a 3 inch exhaust that was mounted inside my existing prefab chimneys flue (I belive the prefab opening is 8 inches). The 3 inch liner goes all the way to the top and is vented (about 18 feet high). They said they mounted the 3 inch cap inside my existing chimney cap for a cleaner finish.

I feel code air coming down the flue and from inside the Pellet surround and I believe it's due to the fact that there's nothing sealing the 3 inch liner from the existing liner at the rear of the fireplace where the damper is. I can see behind and the damper was left in tact with the 3" liner going up through the 8" opening. Can and should I just place some Fire retardant sealant up in the damper opening to prevent the outside air from filtering in? I believe I heard that some people place fiberglass wool of some sort up there to seal openings?

 

[restorer]

I recently had a Country Pellet stove installed and it's working great. It has a 3 inch exhaust that was mounted inside my existing prefab chimneys flue (I belive the prefab opening is 8 inches). The 3 inch liner goes all the way to the top and is vented (about 18 feet high). They said they mounted the 3 inch cap inside my existing chimney cap for a cleaner finish.

I feel code air coming down the flue and from inside the Pellet surround and I believe it's due to the fact that there's nothing sealing the 3 inch liner from the existing liner at the rear of the fireplace where the damper is. I can see behind and the damper was left in tact with the 3" liner going up through the 8" opening. Can and should I just place some Fire retardant sealant up in the damper opening to prevent the outside air from filtering in? I believe I heard that some people place fiberglass wool of some sort up there to seal openings?

Just a suggestion, but if the gap is small, use the rope door gasket material. Hold in place with a little of the gasket cement. This assumes a small less than 3/4 inch space. I don't think fiber glass batting is the answer, but others will be along to suggest other options.

 

[jimkelt]

One option is to put pipe insulation around the 3 inch vent. Your dealer should have this, or should be able to get it.
Other people may have other suggestions, too.

 

[Gooserider]

Sounds like you should have a metal blockoff plate installed to close off that opening for everything except the vent pipe itself.

Does the pipe go all the way to the top of the chimney? If so, then you should also make sure it's sealed at the top as well.

Gooserider

 

[3nickles]

Can't tell about the top of the chimney. I don't have a ladder that tall and it's completely housed inside the existing chimney. They said they used the existing chimney so it would look finished like the rest of the houses Chimney's in the subdivision.

I don't know why they wouldn't seal the top of the chimney from existing liner anyway. I do remember seeing a small vent cap and they were inserting that inside the bigger existing cap?

They should know what they're doing right. They've put in tons of stoves although most of them harmans but I can't believe my country installation would be any different from the harmans.

 

[seaken]

Yes, they should have sealed off the original 8" flue opening with some sort of block-off. Harman suggests using firberglass or ceramic insulation (no paper or foil backing please, insulation only). That should work for your Country also. A sheet metal plate should be used to keep the insulation in place.

(Note: for you wood stove users fiberglass insulation is NOT used. Wood vents should use ceramic wool insulation only)

 

[3nickles]

I'm guessing since I get some draft down the tube that they didn't block off the top.

My father told me to just take some fiberglass insulation and just wad it up around the pipe just over the flue damper. It shouldn't fall down since the damper is still in place and hanges in the middle.

Will this approach work for me? If so, I guess I can just run to the local Hardware store and pick up some fiberglass insulation, strip off the paper backing and stuff it up there right?

 

[seaken]

I'm guessing since I get some draft down the tube that they didn't block off the top.

My father told me to just take some fiberglass insulation and just wad it up around the pipe just over the flue damper. It shouldn't fall down since the damper is still in place and hanges in the middle.

Will this approach work for me? If so, I guess I can just run to the local Hardware store and pick up some fiberglass insulation, strip off the paper backing and stuff it up there right?

Yep, that's what I would do. Make sure the insulation stays in place.

 

[3nickles]

Cool.

Dumb question. The fiberglass insulation isn't combustible is it? Or do I have to look for a specific brand or R-Value?

 

[seaken]

Cool.

Dumb question. The fiberglass insulation isn't combustible is it? Or do I have to look for a specific brand or R-Value?

No. The purpose is to create an air block. In this case you are not using it as insulation.

 

[hearthtools]

My question is if you have 18 feet of pipe why did they only use 3"?

Im not sure about Country but most other pellet stove manufactures say over 15 feed to use 4" pipe.

 

[3nickles]

No idea on that one and I'm not asking the dealer a thing. Too many issues already with trying to get the surround installed correctly from day one..All with the dealertrying to charge me extra. Also can't keep customer communication straight so I'm trying to fix things myself as usual!

Wouldn't the stove be working incorrectly if the 3" wasn't big enough?

 

[begreen]

It depends on the stove and altitude. I'm not sure about the Country Pellet specs, but Quadrafire allowed for 3" up to 26 ft at sea level for the 1200i. Our 1200i ran on 21 ft of 3" continuous pipe and it behaved very well.