Would a damper help Hearthstones Cat Design?

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Dajolu

New Member
Nov 27, 2023
63
New York
I am going to be installing a Green Mountain 60 in my house hopefully with in this month. I am wondering If I should put a damper in or not. I will have roughly 20-25' of chimney length. I have read some posts on this forum talking about the poorly designed catalytic combustor location on the Hearthstones and am wondering if I put the damper right on top of the of the flue that maybe it would help? I am considering getting a Duravent Damper/Adapter for the flue connection.
 
Go to the dealer's showroom and measure the flue collar ID on the stove first before ordering,

It's unfortunate that DuraVent puts the damper into their adapter instead of a regular 6" section of DVL. The adapter is 5 5/8" on the stove end which leads to a sloppy fit on some stoves while a regular section of DVL fits the flue collar very well. I ran into this with our stove and had to purchase a section of 6" DVL, remove the damper from the adapter, and then put it into the 6" section.

Will the flue system be straight up or to a thimble and then up the chimney? There is a big difference between 20 ft and 25 ft of flue. If it's 20' I would not put in a damper. If it's 26' I'd consider it, but probably would try the stove without one first. Reports are that the stove likes a stronger draft, so it's worth trying it out first. If the flue system has a couple of 90º turns in it, then I wouldn't put one in unless it ended up being needed.
 
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Go to the dealer's showroom and measure the flue collar ID on the stove first before ordering,

It's unfortunate that DuraVent puts the damper into their adapter instead of a regular 6" section of DVL. The adapter is 5 5/8" on the stove end which leads to a sloppy fit on some stoves while a regular section of DVL fits the flue collar very well. I ran into this with our stove and had to purchase a section of 6" DVL, remove the damper from the adapter, and then put it into the 6" section.

Will the flue system be straight up or to a thimble and then up the chimney? There is a big difference between 20 ft and 25 ft of flue. If it's 20' I would not put in a damper. If it's 26' I'd consider it, but probably would try the stove without one first. Reports are that the stove likes a stronger draft, so it's worth trying it out first. If the flue system has a couple of 90º turns in it, then I wouldn't put one in unless it ended up being needed.

Thanks for your reply, the pipe is going to have a couple of 45's then into thimble to a tee up a lined chimney. Yea I think I will try it without the damper for now. I all ready ordered and received the duravent adapter (w/o the damper) and some elbows to do some test fitting. The adapter is like you described, loose on the flue collar. I put a double wall 45 elbow on the flue collar to test the direct fit and it is very snug and does not go down on the collar very far. Maybe with a 6" double wall pipe section I will be able to gently tap the pipe down on the collar to get it to seat further/better.
 
Good plan. The 90º turn up the chimney will slow things down a little. If you can, return the DVL adapter. It's not needed.
 
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I read someone here say new cats can be "spikey" at first. My Mansfield took off a couple of times early on and I was glad to have a damper.

It's smoothed out since then but was pretty handy to calm things down.

ETA you guys type faster than I do. My stack is straight in the center of the house. Yours is probably a bit more mellow than mine.
 
I read someone here say new cats can be "spikey" at first. My Mansfield took off a couple of times early on and I was glad to have a damper.

It's smoothed out since then but was pretty handy to calm things down.

ETA you guys type faster than I do. My stack is straight in the center of the house. Yours is probably a bit more mellow than mine.

Not to deviate the conversion to much but is there supposed to be a gasket material to wrap around the cats before installing them? The owners manual describes a wrap of sorts were the instructions that came with the stove basically say to just place the cats on their designated locations. Can you shed light on that for me?
 
Mine are not "gasketed"they weren't when I picked it up from the dealer. They are just sitting in their pocket.
 
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I would check from above. I’ve got the gm80 and i have three sections of cat and they all are individually wrapped with gasket. Installed 3 years ago.