Installing pellet insert in a duplex chimney configuration?

[Pelletman308]

I have a question about the possibility of installing a pellet insert into a home with two fireplaces that share one chimney. The house in question has a stone and mortar duplex chimney that merges into one common outlet just above the upper fireplace. It’s my understanding a dedicated stainless liner needs to be ran up to the top of the existing chimney for the pellet stove. The fireplaces are problematic in this house because if your use the upstairs fireplace it creates a draft smoking out the basement where the lower fireplace is located, even though the flue is closed. Both fireplaces seem to suck more heat out of the house than they provide. The owner would be willing to forgo using the downstairs fireplace anymore if the insert hinders the ability to do that being there would be a liner running into the common chimney. My question is, is this possible? If so how close to the top of the chimney does the liner need to be ran? Also installing a dedicated fresh air intake for the stove would be out of the question because a hole cannot be made in the chimney. The picture is similar to the setup in the home. Any input is appreciated, thank you!

 

[bholler]

I have a question about the possibility of installing a pellet insert into a home with two fireplaces that share one chimney. The house in question has a stone and mortar duplex chimney that merges into one common outlet just above the upper fireplace. It’s my understanding a dedicated stainless liner needs to be ran up to the top of the existing chimney for the pellet stove. The fireplaces are problematic in this house because if your use the upstairs fireplace it creates a draft smoking out the basement where the lower fireplace is located, even though the flue is closed. Both fireplaces seem to suck more heat out of the house than they provide. The owner would be willing to forgo using the downstairs fireplace anymore if the insert hinders the ability to do that being there would be a liner running into the common chimney. My question is, is this possible? If so how close to the top of the chimney does the liner need to be ran? Also installing a dedicated fresh air intake for the stove would be out of the question because a hole cannot be made in the chimney. The picture is similar to the setup in the home. Any input is appreciated, thank you! View attachment 324157

The liner needs to be run all the way out the top of the chimney and sealed with a top plate. And yes that means the other fireplace is unusable

 

[zrock]

The other fireplace would have to be permanently disabled as well so their was not way someone could light a fire in it..

 

[mellow]

Could both fireplaces have pellet inserts installed with damper block offs and a full run of 4" pellet vent to the top of the chimney? I know there would be variables but curious if that could be done.

 

[johneh]

Then they each would need their own vent pipe(chimney liner) not
connected in any way to each other

 

[bholler]

There may even be room for a liner for a wood insert in one of them. Possibly even for an open fireplace in one pellet in the other

 

[Pelletman308]

Thanks guys I’m starting to wonder if it’s even worth it. The fireplace was built like a brick s*** house and running a liner through the flue is going to be a chore, as well as getting on the roof. I’ll have to experiment before even thinking about buying a stove for it