Proper use of the damper in wood furnace?

[blakekr]

I am the proud owner of a US Stoves hotblast wood furnace. This being my second year of wood burning, there is virtually nothing I can claim to know about it. Worse still is oodles of conflicting but colorful advice from generations of well-doers.

The good news is we're actually burning seasoned wood this year. The bad news is I still fail to understand the proper use of the damper installed in the pipe behind the stove. I was told I should shut it as much as possible to avoid having "all the heat go up the chimney." The problem is that all that closing the damper seems to accomplish is transforming a clean and hot-burning fire into a smoky smoldering creosote-forming one. Also, I just read that in modern stoves you should really be adjusting air flow with the front controls, not a damper in the back -- and that the "up the chimney" advice applies best to circa 1800 wood-burning models. Can someone help clarify on this very newbie question?

 

[steam man]

I can't see any big difference between closing in on the inlet or outlet as far as air flow goes. The stack just carries heat out and that loss is the single biggest loss. I have both and use the stack damper as kind of a coarse adjustment and the inlet for finer tuning. My stack is 33' or so and it drafts well. An outlet damper may not be appropriate in a modern appliance depending on the design. I just don't know why.

 

[Blevesque]

Well I can tell you that a damper works wonders. Its a learning curve you are going to have to sit there and see how your furnace reacts, you will find the sweet spot it just takes time. I had this issue a few days ago. It's running great now. Mines a new air tight wood boiler with a combustion fan.

 

[steam man]

Well I can tell you that a damper works wonders. Its a learning curve you are going to have to sit there and see how your furnace reacts, you will find the sweet spot it just takes time. I had this issue a few days ago. It's running great now. Mines a new air tight wood boiler with a combustion fan.

Does New Yorker recommend a barometric damper and did you install one? I presume you didn't have enough air control with the fan inlet or door inlet dampers?

Mike

 

[Blevesque]

New Yorker does say to install a barometric and I did. I still had way to much draft when the boiler was burning good. Now I get the fire going good turn the cast iron damper down to about 75% closed, back the combustion air damper down, stack maintains 350-400 deg. and little to no smoke out the chimney.

 

[blakekr]

Hmm, I think I'm in the wrong forum, my furnace is not a boiler (I originally posted this in the woodstove section which I think is a better fit?) and it sounds like it's designed pretty differently from the others mentioned here.

 

[deerefanatic]

Well, the boiler room is more appropriately the "central wood heating room" so your post is for here..... A wood furnace and wood boiler are much the same, just yours heats air and a boiler heats water.....

 

[jdemaris]

The bad news is I still fail to understand the proper use of the damper installed in the pipe behind the stove. I was told I should shut it as much as possible to avoid having "all the heat go up the chimney." The problem is that all that closing the damper seems to accomplish is transforming a clean and hot-burning fire into a smoky smoldering creosote-forming one.

It all depends on the stove or furnace. Some are well controlled and work fine with the pipe damper wide open all the time.

The pipe damper is a good safety feature so you can shut off air to the chimney in case of a chimney fire.

I've got several old pot-belly coal-wood stoves that need the pipe damper near closed once they're burning hot - otherwise the chimney pipe overheats and turns cherry red.

On my Meyers Woodchuck wood furnace, and my Hearthstone Mansfield woodstove, and also my Thermocontrol 500 wood furnace in my barn - all work fine with the damper wide open.

I've know several people that have the same unit as your's. They like to shut the pipe damper near closed when going to bed a night - it's a nice saftety feature.

Much depends though on your wood, chimney draft, etc. If your fire rages and you have extreme draft in very cold weather, then you might want to find an average setting for your damper - which might be somewhere in the middle.