Damper for Hearthstone Clydesdale Insert

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dtlemoine

New Member
Dec 17, 2019
2
Framingham, MA
First off - thank you to this community for already answering a ton of my questions as I got up to speed on burning in a wood stove. I've read countless threads and the amount of awesome info and tips on this forum is staggering.

My story - we live in the metro-Boston (metro-Worcester??) area, and installed a Hearthstone Clydesdale last winter. The insert is hooked up to an exterior chimney, approx 35' tall. The dealer used a 5.5" non-insulated flexible liner, and did not install a block off plate. I'm told it was packed with roxul at the top of the chimney.

Since then I've packed the liner at the top of the smoke chamber with more roxul to help with insulation... a little. I've also fashioned a rudimentary block off plate with sheet metal backed with more roxul. This has helped keep the outside air out of our living room. The 5.5" liner remains, and we have plans to replace it with a proper 6" insulated liner to mate with the 6" opening on the stove.

First off - the stove is awesome. I love the large viewing window, specifically the reason we went with the Clydesdale. The stove puts out a TON of heat when it's rolling, and is more than enough to heat a 2800 sq foot house during shoulder season, and definitely helps with the propane bill in the middle of winter.

With that said, I have two issues with the stove.

1) the stove absolutely CRUSHES through wood. The "doghouse" acts like a laser beam and blows a hole through whatever wood is stacked on the bottom of the stove - the primary intake seems to have too much velocity. I can't get more than 4-5 hours of quality burn from a loaded stove. The wood is all well seasoned (all local hardwood, purchased from the dealer "seasoned" and let it sit for another full year, tested in the high teens for MC). I finally broke down and purchased a manometer, and we're getting between -.16 and -.2 in H2O. Hearthstone calls for -.06 to -.1, so we have roughly double the draft, well over the recommended specs.

2) the stove spills smoke like crazy on re-loads, no matter how long I leave the door cracked before opening wide, no matter how slowly I open it, and no matter how wide the window next to the stove is open when I reload. The installer had to ovalize the liner to pass through the existing damper, so I assume this is creating a choke point. I'm hoping I can rule out stack effect as the window(s) open near the stove should equalize the pressure, right??

So the question is - how can I reduce the draft down to acceptible levels so I'm not burning through wood so quickly, and dumping all that precious heat up my chimney? I've spoken with a few chimney sweeps, as well as Hearthstone directly, and no one has been able to offer any usable advise. Hearthstone doesn't make a damper kit for this stove and no one has been able to figure out how to install one in an accessible place.

And how can I do so in a way that doesn't make the smoke spillage worse?

Will moving to the rigid 6" liner make my spillage problem better (hopefully!!)? Conversely, would it make my draft problem worse??

Looking forward to hearing from the experts. Thanks in advance for reading!
 

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Geoff C

Burning Hunk
Oct 29, 2011
137
PA
Mine spills smoke. I let it burn down To coals before reloading. Have you don’t the dollar bill test on the door gasket? I don’t know if it’s the size of the door or what but my gasket needs replacement every year. When the gasket was bad the stove was definitely eating more wood


Sent from my iPhone using Tapatalk
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
26,216
central pa
Mine spills smoke. I let it burn down To coals before reloading. Have you don’t the dollar bill test on the door gasket? I don’t know if it’s the size of the door or what but my gasket needs replacement every year. When the gasket was bad the stove was definitely eating more wood


Sent from my iPhone using Tapatalk
Have you tried adjusting the latch instead of changing the gasket?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
26,216
central pa
First off - thank you to this community for already answering a ton of my questions as I got up to speed on burning in a wood stove. I've read countless threads and the amount of awesome info and tips on this forum is staggering.

My story - we live in the metro-Boston (metro-Worcester??) area, and installed a Hearthstone Clydesdale last winter. The insert is hooked up to an exterior chimney, approx 35' tall. The dealer used a 5.5" non-insulated flexible liner, and did not install a block off plate. I'm told it was packed with roxul at the top of the chimney.

Since then I've packed the liner at the top of the smoke chamber with more roxul to help with insulation... a little. I've also fashioned a rudimentary block off plate with sheet metal backed with more roxul. This has helped keep the outside air out of our living room. The 5.5" liner remains, and we have plans to replace it with a proper 6" insulated liner to mate with the 6" opening on the stove.

First off - the stove is awesome. I love the large viewing window, specifically the reason we went with the Clydesdale. The stove puts out a TON of heat when it's rolling, and is more than enough to heat a 2800 sq foot house during shoulder season, and definitely helps with the propane bill in the middle of winter.

With that said, I have two issues with the stove.

1) the stove absolutely CRUSHES through wood. The "doghouse" acts like a laser beam and blows a hole through whatever wood is stacked on the bottom of the stove - the primary intake seems to have too much velocity. I can't get more than 4-5 hours of quality burn from a loaded stove. The wood is all well seasoned (all local hardwood, purchased from the dealer "seasoned" and let it sit for another full year, tested in the high teens for MC). I finally broke down and purchased a manometer, and we're getting between -.16 and -.2 in H2O. Hearthstone calls for -.06 to -.1, so we have roughly double the draft, well over the recommended specs.

2) the stove spills smoke like crazy on re-loads, no matter how long I leave the door cracked before opening wide, no matter how slowly I open it, and no matter how wide the window next to the stove is open when I reload. The installer had to ovalize the liner to pass through the existing damper, so I assume this is creating a choke point. I'm hoping I can rule out stack effect as the window(s) open near the stove should equalize the pressure, right??

So the question is - how can I reduce the draft down to acceptible levels so I'm not burning through wood so quickly, and dumping all that precious heat up my chimney? I've spoken with a few chimney sweeps, as well as Hearthstone directly, and no one has been able to offer any usable advise. Hearthstone doesn't make a damper kit for this stove and no one has been able to figure out how to install one in an accessible place.

And how can I do so in a way that doesn't make the smoke spillage worse?

Will moving to the rigid 6" liner make my spillage problem better (hopefully!!)? Conversely, would it make my draft problem worse??

Looking forward to hearing from the experts. Thanks in advance for reading!
With a 35' chimney clearly you are way over the specified draft. The only way to do a damper in an insert is by adding a price of rigid liner then fabricating a linkage that is then run through a hole drilled in the surround
 

dtlemoine

New Member
Dec 17, 2019
2
Framingham, MA
With a 35' chimney clearly you are way over the specified draft. The only way to do a damper in an insert is by adding a price of rigid liner then fabricating a linkage that is then run through a hole drilled in the surround
Thanks! After calling a few local chimney contractors, was finally able to find one willing to do this (most just looked at me with a confused face). Going to do a 2' rigid section between the stove adapter and the rest of the liner, which will house the damper. Will need to drill a hole in either the surround or the brick to run the damper handle through, but this should allow us to do the proper 6" insulated liner but still retain the ability to keep the draft in check. Planning to remove the old fireplace damper completely, which keeps us from having to ovalize any piping, restricting the draft while the door is open for reloads. Fingers crossed.