Chimney liner and gas furnace vent help

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GreatOutdoors

New Member
Dec 17, 2016
3
Missouri
Ive looked everywhere and can't find answers to my problem. I have a fireplace in my basement and want to install an insert. Putting in the chimney liner would be easy enough except my gas furnace vents into the same flue as the fireplace. Venting the furnace out a sidewall would be a 12' horizontal run and it's not a high efficiency furnace. At the top of the chimney I have three flue tiles, one to the basement fireplace/furnace, one to an insert upstairs, and the center one appears to be nothing but goes down out of sight. What I want to do is run a liner up the flue for the basement insert and end it in the same flue at the top. Then I want to run a stainless liner up the same flue to vent the furnace, but 2-3' from the top reach down and cut an opening connecting the basement flue to the unused flue so that I can end the furnace vent with a proper cap. Does this sound reasonable or am I way off?
 
Ive looked everywhere and can't find answers to my problem. I have a fireplace in my basement and want to install an insert. Putting in the chimney liner would be easy enough except my gas furnace vents into the same flue as the fireplace. Venting the furnace out a sidewall would be a 12' horizontal run and it's not a high efficiency furnace. At the top of the chimney I have three flue tiles, one to the basement fireplace/furnace, one to an insert upstairs, and the center one appears to be nothing but goes down out of sight. What I want to do is run a liner up the flue for the basement insert and end it in the same flue at the top. Then I want to run a stainless liner up the same flue to vent the furnace, but 2-3' from the top reach down and cut an opening connecting the basement flue to the unused flue so that I can end the furnace vent with a proper cap. Does this sound reasonable or am I way off?
Are you sure that unused flue is not what the furnace is venting into? If not I would figure out where it goes and try to vent into that flue. What size opening is the flue that the fireplace and furnace share? what size vent does your furnace have?
 
Venting the furnace into the unused flue was my original plan but couldn't find where they came together. Turned the furnace on to run the fan powered vent, blocked off the shared chimney at the top to try to force vent air out unused chimney and no luck. Shared chimney is 13x13, furnace vent is 4", unused chimney is 9x9 with only about 2.5" separating the two flues. I think I can reach down with an angle grinder in both chimneys and cut enough to be able to knock a section out.
 
Probably worth dropping a camera down the flues to make sure where they go. Bholler would know best but you may be able to fit the gas flue and a 6" liner down a 13x13 so you don't have to go knocking holes in the flue.
 
Probably worth dropping a camera down the flues to make sure where they go. Bholler would know best but you may be able to fit the gas flue and a 6" liner down a 13x13 so you don't have to go knocking holes in the flue.
Yeah an insulated 6" and an insulated 4" should fit. But I would still try to vent the furnace into that unused flue I would say get a pro out with a camera.
 
I'm fairly certain from what I can see and from blocking the flue with the power vent running the two flues never come together. That limits me to running both liners up the one flue. The only reason I want to push the furnace vent into the other flue near the top is to have weather proof flue caps, basically I don't know how I would terminate both liners in a single flue, have it be weather proof, and not look like a hack job. I'm trying to get a chimney guy out but haven't got him to show up yet. Thanks for your help and I'll post what I end up with.
 
I'm fairly certain from what I can see and from blocking the flue with the power vent running the two flues never come together.
no but that other flue has to go somewhere. If it goes down to the basement you could open up a hole into it so it could contain the liner for your furnace.
 
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