Hearthstone Craftsbury in a tight home, strong draft.

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49thparallel

New Member
Jan 7, 2025
2
North Dakota
This is my second winter in our new well insulated and tight SIP house. We brought the Hearthstone Craftsbury from our previous smaller but much less insulated house into the new one.

I immediately discovered that the draft of the new chimney is quite strong and apparently more than the stove can handle. It is a straight 6” flue with double wall stove pipe for the first 6’ to the ceiling and 20’ of stainless triple wall Security chimney from there.

I had run this stove for 5 years in the previous house and never had issues controlling it. The first fire in the new ran out of control quickly and I had to plug the air intake on the back of the stove.

I have since added a probe type flue gas thermometer and damper above the stove and have been very careful about how I build fires, tightly stacking the wood and burning top down.

While I can keep things under control, it requires vigilance and shutting down the air and damper very early to keep the flue gas below 800. Also, despite having clearances 30% over the minimums to combustibles for a corner installation, I’ve seen the drywall get upward of 160f on a regular basis. Additionally, given the fast, hot burns that are inevitable it is impractical to use the stove for much more than ambiance in the evening.

I am considering moving to a Blaze King Sirocco 30.2 in order to achieve a lower and slower burn. In the experience of fellow forum goers, would doing so address the issues I’m having or am I just throwing money at the problem? Can the Sirocco handle a strong draft (as near as I can measure 0.06” when all is shut down and 0.08 or more when opened up) and would the ability to burn lower fill the need I have?

It just so happens that in arbitrarily oversizing the clearances and hearth pad for the Craftsbury, I made it the exact size necessary for the Blaze kings. Perhaps it is providence…
 

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I would first try adding a second key damper.

Too much draft is not good for a Bk either. Some folks see their cat getting clogged by fly ash sucked into it and cats don't live long with overdraft.

If a second damper works, you spent $20 rather than a few thousand, and are operating a stove you know and had life left.

That said, sometimes things may work better if the secondary air is restricted. Other folks (with tube stoves) know better.
@Todd maybe (though he doesn't have this model).
 
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Looks like you already have a pipe damper but something else to try is finding your unregulated boost air which is usually located at the lower front of the firebox under the glass. Blocking that should give you a little better control. I also wouldn’t rule out partially blocking some secondary air wherever that comes in with magnets.

every stove pretty much is set up and tested to burn on a 15’ chimney so with taller chimneys you really need to adjust the draft with a damper or cut back so air somewhere. Especially for non cat stoves since they let in more air than a cat stove will.
 
Hard to say for sure but yeah all these modern stove are tested on a 15’ chimney with optimal draft and there’s so many variables it makes it tough to figure the right way to go.
 
Can you buy a manometer (up to 0.2) and measure the draft during a burn?
That'll tell you.