Should have added a damper years ago

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rudysmallfry

rudysmallfry

Minister of Fire
Nov 29, 2005
617
Milford, CT
Okay, so it only took me 9 years to figure this out. Some of you are familiar with my broken record complaints about short burn times, stove not getting hot enough, blah blah blah. I had toyed with the idea of adding a damper several times, but always talked myself back out of it for one reason or another. This year, I decided it was worth trying out for the $9 that it cost. I loaded my stove up, got the pipe temp up to about 400, closed the damper about half way, did the same with the air and proceeded to get much warmer soapstone and about 3 hour longer burn time. Why didn't I do this sooner??? Sometimes the fixes really are that easy.
 
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rudysmallfry said:
Okay, so it only took me 9 years to figure this out. Some of you are familiar with my broken record complaints about short burn times, stove not getting hot enough, blah blah blah. I had toyed with the idea of adding a damper several times, but always talked myself back out of it for one reason or another. This year, I decided it was worth trying out for the $9 that it cost. I loaded my stove up, got the pipe temp up to about 400, closed the damper about half way, did the same with the air and proceeded to get much warmer soapstone and about 3 hour longer burn time. Why didn't I do this sooner??? Sometimes the fixes really are that easy.
Click to expand...

I can't remember, so I'll ask out of curiosity.... What are the dimensions of the chimney this stove is hooked too?

Glad you are getting the results you had been hoping for!

pen
 
6" single wall 24" to 90 degree elbow, 18" to wall thimble, 18' class A chimney. Why you gonna talk me out of it after the fact?
 
Not trying to talk you out of it at all!

Always trying to work on problem solving / understanding how these things run and I was curious to see how much chimney / draft you were working with.
 
I'm just busting ya. I'm honestly not sure how much draft the chimney pulls. I had it measured the first year when I knew my burn times were not up to snuff. If was within the specs of the stove. I had a few near runaway fires last year which got me thinking more seriously about the damper. It's all good now.
 
Sounds good!

I have a similar chimney and also installed a damper. It however is mostly used for extremely cold nights and for when my wife runs the stove and needs an emergency brake!

pen
 
Interesting....any reason why a damper wouldn't help in most configurations?
 
siddfynch said:
Interesting....any reason why a damper wouldn't help in most configurations?
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The damper was used by most configurations back before the new stove designs, as you would want to hold the heat in the stove and not send it up the chimney like a fireplace. Today the EPA stoves work with the amount of air coming into the stove as they burn the gases. The damper will only help if the draw is too large and pulls too much combustion air into the firebox. Today we slow the burn by closing or shutting down the combustion air to the stove.
 
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What happens, in my case, where I have an insert and the air control is shut down all the way but the fire won't cut back? I have a 30 foot high liner in my chimney, so I am guessing the draft is to strong!
 
Oregon aloha said:
Today we slow the burn by closing or shutting down the combustion air to the stove.
Click to expand...

Too bad it doesn't work like that with EPA non-cats. Turns out, the secondary air system of most stoves is full throttle all the time. So if you have a strong enough chimney, the stove will get as much air as it needs to operate well outside of what the engineers expected sometimes causing overfire and usually causing a higher stove temp than desired. The stove was designed around a particular minimal chimney system to work properly and meet emissions standards on that chimney only.

Adding a flue damper brings the user back into control. Makes the user able to defeat emissions controlling designs and allows the user to optimize the burn for his chimney.

They are a pain to clean around if in an otherwise vertical setup.
 
Highbeam said:
Too bad it doesn't work like that with EPA non-cats. Turns out, the secondary air system of most stoves is full throttle all the time. So if you have a strong enough chimney, the stove will get as much air as it needs to operate well outside of what the engineers expected sometimes causing overfire and usually causing a higher stove temp than desired. The stove was designed around a particular minimal chimney system to work properly and meet emissions standards on that chimney only.

Adding a flue damper brings the user back into control. Makes the user able to defeat emissions controlling designs and allows the user to optimize the burn for his chimney.

They are a pain to clean around if in an otherwise vertical setup.
Click to expand...

I think I may benefit from one as well. I have a 28 foot chimney, and I seem to have difficulty maintaining a slow burn in cold weather. I'm not sure if i can install a damper with my setup, however, becasue I rear vent my stove and the stove is set up very close to the brick wall behind it.
 
Bagelboy said:
What happens, in my case, where I have an insert and the air control is shut down all the way but the fire won't cut back? I have a 30 foot high liner in my chimney, so I am guessing the draft is to strong!
Click to expand...
It seems like around 30 feet is where excess draft problems start to happen. Just based on threads I've read. Then dampers are useful.
 
In these cases where excessive draft is a problem, it may be worth finding the secondary air inlet on the stove and using some metal tape or a magnet to block a bit of it to reduce the amount of air the secondaries get.

Here's an article that is worth reading on the topic (Florida Bungalow Syndrome) http://www.gulland.ca/florida_bungalow_syndrome.htm
 
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Yeah modifying air inputs beats damping exhaust. You don't tune a car by blocking off part of the exhaust pipe. You adjust the fuel/air mix.
 
BrotherBart said:
Yeah modifying air inputs beats damping exhaust. You don't tune a car by blocking off part of the exhaust pipe. You adjust the fuel/air mix.
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You usually post the link I gave. Didn't mean to steal your thunder!
 
Nah. I have been waiting to see it show up this year. :)
 
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pen said:
In these cases where excessive draft is a problem, it may be worth finding the secondary air inlet on the stove and using some metal tape or a magnet to block a bit of it to reduce the amount of air the secondaries get.

Here's an article that is worth reading on the topic (Florida Bungalow Syndrome) http://www.gulland.ca/florida_bungalow_syndrome.htm
Click to expand...

Thanks I will try that first.
 
I may try this, the hole in my plate that seals off the stove is about the size of a quarter or so, I'll cover half the hole and see what happens . Does this cause dirty glass ?
 
etiger2007 said:
I may try this, the hole in my plate that seals off the stove is about the size of a quarter or so, I'll cover half the hole and see what happens . Does this cause dirty glass ?
Click to expand...

The airwash is part of the primary air on stoves that I am aware of, not the secondary air system.
 
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teutonicking said:
Thanks I will try that first.
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With a hybrid like you have I would talk to Woodstock first. Balance between secondary burn and cat operation could get a little tricky where with a straight non-cat that isn't an issue.
 
Well, I'm glad somebody posted the article. It's answered a lot of questions I've had.

pen said:
it may be worth finding the secondary air inlet on the stove and using some metal tape or a magnet to block a bit of it to reduce the amount of air the secondaries get.
Click to expand...
Why just the secondary supply rather than the main air inlet?
 
Sprinter said:
Well, I'm glad somebody posted the article. It's answered a lot of questions I've had.


Why just the secondary supply rather than the main air inlet?
Click to expand...

Because the secondary supply is unregulated and what makes things go nuclear with too much draft.

Plus, you still need a good amount of primary to get the thing started.

Also, your air control regulates the primary.
 
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Bagelboy said:
What happens, in my case, where I have an insert and the air control is shut down all the way but the fire won't cut back? I have a 30 foot high liner in my chimney, so I am guessing the draft is to strong!
Click to expand...

A Valkyrie...

Oh, yeah.. different stoves maybe able to be modified to decrease the air being let in, even when the draft control is set to zero. (don't tell the EPA)
 
etiger2007 said:
I may try this, the hole in my plate that seals off the stove is about the size of a quarter or so, I'll cover half the hole and see what happens . Does this cause dirty glass ?
Click to expand...

That plate is your primary air and the hole is there to limit the amount that you can turn down the primary air. This hole is not the typical cause for runaway non-cats. Look elsewhere for the secondary air inlet which is unthrottled.
 
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