To Add A Damper or Not?

[soupy1957]

I brought this out in another Thread, and I'm not certain I got a complete answer...........

One of the items that I had asked about when we were negotiating with the Wood Stove place we were buying from (who did our Installation as well), and one that I still believe could be useful, is a Damper in the Flue Pipe, to assist with regulating airflow.

Yes, there is a damper on the stove itself, so it may be overkill, I dunno.

I know that some of you are for it, and some are against it, (deeming it unnecessary, or downright dangerous, I suppose) but I'm wondering what the actual functional value would be, when I'm already using a damper on the stove itself.

I'm willing to install one if it has merit.........what do YOU think of having one along with the one already in the stove?

-Soupy1957

 

[BrotherBart]

If you put a damper in that pipe then forget about cleaning the chimney without removing the connector pipe.

 

[soupy1957]

Yep...........that's right.........definitely a down side to installing one. I have to take the Probe Thermometer out as it is, but certainly the section with the damper WOULD have to come out. Valid point.

-Soupy1957

 

[ANeat]

The only times Ive read about where a damper was "necessary" was when a specific instalation had some great ammout of draw that caused over firing even when throttled back at the stoves controls.

If you can throttle back the stove to your satisfaction with an open flue then a damper wouldnt be necessary

 

[cmonSTART]

Personally I wouldn't unless I really NEEDED one to control the stove. You can always add one later.

 

[Todd]

How tall is your chimney? I think when you get in the 25-30' range it could be a good idea for a damper. Most stoves are tested at 14-16' so manufactures set them up to burn best that way. Another idea that's been batted around on here is to modify the EPA rigged air supply so it cuts down the amount of combustion air more.

 

[begreen]

Agreed. I had a damper, so I tried it. Then removed it. Turned out our draft is just about right without tinkering.

 

[fossil]

Redundantly, I add: install and burn your stove first without a damper. Should you find you want one (which I highly doubt) it's really no more difficult to install after the fact than before. Rick

 

[freeburn]

I was always under the impression that a damper was there in case you had a runaway fire and needed to help damper things down quickly, but that being said, an EPA stove shut-down to zero might do the same thing save the secondary air.

 

[soupy1957]

Todd: Not exactly sure HOW tall my chimney is.....I'll guess 15 Feet

Fossil: I had my stove installed last November, and burned wood from then til March of last year. I don't know that
I "need" it, but figured it might help me by using it as an alternative to, or in combination with the stoves air flow
control.

Freeburn: I have found that my EPA-Rated stove's "secondary burn" seems to never get to the kind of complete
burn (not all tubes with holes, showing flame; perhaps one row of tubes at best), that I thought it would
when I shut the stove's air flow control all the way down. Those hot burns sometimes seemed so intense
at times, that I thought (perhaps mistakenly) that I could get better results from the secondary burn with
a flue damper. This may not be clear thinking, but it was an idea.

In the end, I strongly doubt that I will be putting one in.............but I thought the topic worth revisiting.

-Soupy1957

 

[Rob From Wisconsin]

Our chimney is approx. 25' tall, and we have found the damper to be rather beneficial at times.
It almost behaves like a "catalyst", slowing-down the flow of exhaust and generating much more
activity at the burn tubes. It also adds a good hour or so to our burn times, along with slowing
down heat rising up & out of the chimney. Of course, we can't use it to this effect all of the time,
and it may also be related to us having a soapstone stove, perhaps......

 

[Backwoods Savage]

If it is not broke, then do not attempt to fix it.

 

[firefighterjake]

Usually dampers aren't necessary unless . ..

a) you have an excessive draft due most often to a tall chimney
b) you want one in case of a chimney fire . . . in which case I would suggest that rather than spending the extra time installing this (and this would mean drilling even more holes in your stove pipe) that instead you would want to do a better job in seasoning your wood, burning at hot enough temps and spend more time inspecting and cleaning the chimney
c) you want to install one since that's what your grandpa always had on his woodstove and you're of the mind that since it was good enough for him it is good enough for you.

 

[Wood Heat Stoves]

I was always under the impression that a damper was there in case you had a runaway fire and needed to help damper things down quickly, but that being said, an EPA stove shut-down to zero might do the same thing save the secondary air.

chimfex extinguisher

 

[bsearcey]

I have a damper installed on the flue collar of my stove. It comes in handy with my setup because my chimney is around 23' and I get really strong drafts. It helps to slow things down. In fact the manual for my stove suggested adding the damper in order to increase burn times. I don't think that is standard practice anymore, but my stove is an 83 catalytic so just at the time when the industry was starting to transition over from the smoke dragons.

 

[soupy1957]

bsearcey: I agree that it is not commonly done much anymore.............when we were finalizing our agreement with the company that sold us our stove and installed it, I asked about having a Flue damper, and he said the same thing. Not that I couldn't have pressed him til he got me one as part of my installation, but rather that he wasn't "used to folks asking for one," which implied that it was not commonly done these days.

-Soupy1957

 

[EJL923]

The draft on my insert is almost too good. The burn times suffer greatly due to this. My focus has been being able to make the stove adjustable, and not the pipe.

Why? For one, i have an insert and will not be able to adjust the damper. The other is to me it doesnt make sense to block the byproducts after the burn. Once the wood has burned, i want any leftover exhaust to quickly exit, hopefully cleanly. Think about a car exhaust. The exhaust itself is as free flowing as possible. All air is regulated through the engine. You dont hear anyone saying i am blocking my exhaust to reduce the gas consumption. You would only do that in conjuction with an air intake/gas intake modification. The damper is also a sticking point for creosote and another hole in the pipe.

Todd is correct, most stoves are designed for the 15' chimney height. Do a search on google for the florida bungalow effect for wood stoves, it will explain all of this. My chimney is 23' tall, so i am modifying how much air is able to be pulled into my stove. Due to the increased draft, you can adjust down the intake air past manufacturer adjustments and still burn cleanly. I proved this over the winter. I was having very low burn times, in the 3-4 hour range. I adjusted the main air intake, as well as blocked one of the zipper intakes and increased my burn times about 50%. It is still low compres to others, but i burn my stove fairly hard to heat a larger area than the stove was designed for.

Im going to stop now before i go further into one of my engineering tangents. In summary, i am against it. I am re-engieering my stove to fit my setup while still being able to burn clean.

 

[vvvv]

I was always under the impression that a damper was there in case you had a runaway fire and needed to help damper things down quickly, but that being said, an EPA stove shut-down to zero might do the same thing save the secondary air.

chimfex extinguisher

wet newspaper kept in plastc bag for the occasion

 

[vvvv]

Once the wood has burned, i want any leftover exhaust to quickly exit, hopefully cleanly.
pyrolysis? I dont think u understand phases of wood burning

 

[begreen]

Does that mean no more MagicHeat draft reducer?

 

[oldspark]

Once the wood has burned, i want any leftover exhaust to quickly exit, hopefully cleanly.
pyrolysis? I dont think u understand phases of wood burning

Hmmm that is a good point, the new stoves are not like the old ones.

 

[EJL923]

As a matter of fact, i do understand the phases of woodburning. Maybe i didnt word it correctly. The problem with some people in these forums is instead of them asking you to explain yourself, the chests get bumped out and they get ready to pounce. Instead, i get jumped on by stephen hawking/doogie howser. All i am saying is in the event something isnt burning cleanly, i want it to be able exit quickly rather than stew in the chimney. Now if you always have perfect wood and have the time to sit there and monitor your stove 24/7, then good for you. I dont have that problem, but i like to think a step ahead in case i come across some less than perfect fuel.

 

[oldspark]

I should have deleted the part about you not understanding phases of wood burning in my quote, sorry. I think I got confused, I agree with ejl923 about the damper, on the new epa stoves I do not think it makes sense. I suppose if you have a super sucker it could help out.

 

[soupy1957]

This thread was written because of the fact that I hadn't yet really gotten a handle on why it is that when I close down my airflow control on my stove, it seems to nearly kill my fire altogether. Sure.........the air is being cut back and without air, a fire won't burn ...........but I thought the dampers on the new stoves were supposed to STILL allow SOME airflow.

It's just a learning curve thing. I had plenty of chances last season to get a feel for the system we own, and I DID often put the damper 1/2 way closed after the initial fire got settled in. I'll master it sooner or later. Just thought that perhaps the damper that you can get for the flue pipe, would perhaps be a bit more manageable.

I have seen the airflow diagrams that Avalon puts out there for public consumption, but I have YET to see any actual breakdown of the damper itself; how it sits in the stove, what it is.........etc.. Someone in here put an image at one point, of the design, but it was not clear what I was looking at. Since I will not be tearing my stove apart (perhaps in 30 years I may) to see how it is constructed, I'll have to try and visualize it somehow.

It's enough to say, that I get too much "shut down" with the air control fully "forward" (closed) and I thought I might be able to have more (better) control, with a damper in the flue.

-Soupy1957

 

[oldspark]

If you are having problems with the fire dying down after you close the air control half-way you do NOT want a damper period, it will make it worse.