Manual Pipe Dampers - A Matter of Perspective

Manual Pipe Dampers - A Matter of Perspective

PostBy: Lightning On: Thu Dec 12, 2013 9:24 am

Does a manual pipe damper hold heat in a stove?

This came up on another thread and thought it deserves a thread of its own. To me, It's a matter of perspective. Is the glass half full or is it half empty?

I think everyone could agree that in order for heat to be lost up a chimney, it needs a vehicle to catch a ride on. In this case, That vehicle would be excess air. Air in equals air out. Let's consider two scenarios. A tight well sealed stove and a leaky not so well sealed stove.

With the well sealed stove (with independent primary and secondary controllable combustion air) the manual damper weakens or strengthens the negative pressure in the fire box. This pressure dictates how much volume of combustion air enters the stove and effectively controls the burn rate. I can slow the burn rate which makes the fire box cooler by closing the manual damper which is exactly what I see happen.

Now for the leaky stove with fixed secondary combustion air. With excessive air (manual damper open), heat is carried up and out the chimney and also this excessive air can have a cooling effect on the fire box. With manual damper closed, the excessive air coming in is limited so those ill side effects are lessened.

So, in a technical aspect does the manual damper "hold heat in the stove"? In my opinion, not really... It limits air in by limiting air out. That's just my perspective. :-)
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: franco b On: Thu Dec 12, 2013 6:13 pm

I think you are right and it is only a case of lowering the draft when closing the pipe damper.
franco b
 
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: KLook On: Thu Dec 12, 2013 8:25 pm

I agree, 100%. It can be applied to car engines. If you put a bigger manifold and carbs on a stock engine, it is useless unless you open up the exhaust and free up the pipes. (less restriction) Put a big old load of coal in there and close the MPD and choke it down. However, I do believe stoves have sweet spots and can be maintained in that mode. That is why I favor Baro's because they automatically adjust to keep it sweet no matter what the wind/temp/whatever is doing.

Kevin
KLook
 
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Stove/Furnace Make: Harman (Back In Maine)
Stove/Furnace Model: VF 3000


Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: oliver power On: Thu Dec 12, 2013 10:22 pm

Yes Lightning, I too believe you are correct, or at least on the right track. Myself, it's hard to describe to people who have only burned in modern stoves. In the older stoves, we always had a manual pipe damper. They were not air tight stoves. If no manual pipe damper, or an open manual pipe damper, you couldn't get any heat off the stove. The house would be cool. All the heat went up the chimney. As soon as the manual pipe damper was turned, almost instantly, heat radiated out around the stove. I mean lots of heat. It was a night and day difference. It was the difference of being warm, and not being warm. Or should I say; Darn right cold! We would all huddle around the stove in hopes to keep warm. When the air tight stoves came along, it was recommended not to use manual pipe dampers. Fast forward; here's my observation. We always burnt wood. A wood fire favors combustion air from the base of the fire, and up. Yes, we were able to set air flow to the fire. However, being non-air tight, air leaked in from many other places, like ash pan door (if it had one), load door, seams, controls, cracks, etc.. So many places that the only one place to control air flow was at the smoke pipe. A manual pipe damper would restrict air flow, keeping heat in the stove. In the day, no one used the term "restrict air flow". It was said that a damper holds the heat down. No one called it a manual pipe damper. It was called Example; a 6" stove pipe damper. Here's one for ya; Last year, my brother installed a manual pipe damper in the pipe coming off the HITZER 50-93. Said it made quite a difference. This year, he replaced the stove pipe, and left the damper out. Must not have made the big difference he thought.
oliver power
 
Stoker Coal Boiler: KEYSTOKER Kaa-2
Hand Fed Coal Stove: Hitzer 50-93 & 30-95, Vigilant (pre-Vigilant-II)
Baseburners & Antiques: MANY (Mostly when burning wood)
Stove/Furnace Make: HITZER / KEYSTOKER
Stove/Furnace Model: 50-93 & 30-95 , Kaa-2

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: jschaefer7406 On: Fri Dec 13, 2013 11:45 pm

Hello all,

I've always had both installed, but just this year added a permanent manometer. With the baro set to .04", I have yet to use the MPD :(.

I can see that, by closing it, my draft falls from .04" to .03". But I haven't really noticed any less coal usage or additional heat with it closed (as some suggest they're used for). Is it not as noticeable because mine is a hot air furnace (hand fired, no stoker) in the basement and not a stove?

Thought I understood the purpose of each, and in the previous years I've closed the MPD on cold days. Haven't touched it in weeks this year though, not seeing any difference :(.

Thoughts?

Thanks,

Joe
jschaefer7406
 
Stove/Furnace Make: Kogen
Stove/Furnace Model: Keystoner

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: KLook On: Sat Dec 14, 2013 12:04 am

NO thoughts......it is just as i would expect. 8-) The baro is the way to go.

Kevin
KLook
 
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Stove/Furnace Make: Harman (Back In Maine)
Stove/Furnace Model: VF 3000

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: Lightning On: Sat Dec 14, 2013 3:50 am

jschaefer7406 wrote:I can see that, by closing it, my draft falls from .04" to .03". But I haven't really noticed any less coal usage or additional heat with it closed (as some suggest they're used for). Is it not as noticeable because mine is a hot air furnace (hand fired, no stoker) in the basement and not a stove?

Its likely that the difference in pressure isn't enough to notice coal usage and/or heat output difference.

KLook wrote:NO thoughts......it is just as i would expect. The baro is the way to go.

I agree with KLook :D

franco b wrote:I think you are right and it is only a case of lowering the draft when closing the pipe damper.
Yes sire, that sums it up..

Thank you for everyone's input!
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: dcrane On: Sat Dec 14, 2013 6:41 am

ummm... anyone gots a Baro for sale :surrender: hahahaha
dcrane
 
Hand Fed Coal Stove: Crane 404

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: freetown fred On: Sat Dec 14, 2013 7:35 am

These baro opinions are all well in good if it works well with your set-up. I figure with 2000 sq of broken up 250 yr old farmhouse staying at a nice toasty 74*--I'll keep my MPD just as she is--MPD, 3 ton of BLASCHAK & the old HITZER 50-93 all work real well together on the hill here. If something works for ya---enjoy it. I'm far from a salesman ;)
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: Lightning On: Sat Dec 14, 2013 8:27 am

Fred Bro, hey partner please don't get the wrong impression. I'm not lookin to throw the manual damper under the bus. Many like yer self use a manual exclusively and it works just fine. I was merely attempting to get to the bottom of the science lol

I know, I know it ain't no rocket :lol:
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: freetown fred On: Sat Dec 14, 2013 9:09 am

Hell Lee, nobody EVER gets to the bottom of that science dribble--it changes every time a different brainiac has a new brain fart--are eggs good for us this year, I don't think they were 2 yrs ago? :bang: :clap: toothy
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: rberq On: Sat Dec 14, 2013 9:50 am

Lightning wrote:I was merely attempting to get to the bottom of the science lol
I know, I know it ain't no rocket :lol:

Well, actually it IS sort of a rocket. Read up on the efforts to develop a clean and efficient and inexpensive small cook stove for the millions in the world who still burn wood/peat/dung etc. to cook their meals. It turns out making a good one is MUCH harder than it sounds, and tiny differences in stove configuration can make a huge difference in heat output, efficiency, and clean burning. If that is true for cook stoves, then why not for coal stoves and dampers? That's probably why their owners have such enthusiasm for the antique base burners that were the pinnacle of coal-burning design. (Watch out! -- incoming response from CoalCracker is anticipated.) :P
rberq
 
Hand Fed Coal Stove: DS Machine 1300
Coal Size/Type: Nut -- Kimmel/Blaschak/Reading
Other Heating: Oil hot water radiators, propane

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: tcalo On: Sun Dec 15, 2013 5:39 pm

Here's something to ponder...with the MPD open 100% the air is free to move through the coal bed and out of the chimney with no restrictions. If the MPD is closed 100% the draft is decreased, according to my manometer reading. If the air settings remain the same would the air entering the firebox remain the same or decrease due to the decreased draft of the MPD position?
tcalo
 
Hand Fed Coal Stove: Chubby Coal Stove
Coal Size/Type: Nut Anthracite

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: Lightning On: Sun Dec 15, 2013 5:44 pm

tcalo wrote:Here's something to ponder...with the MPD open 100% the air is free to move through the coal bed and out of the chimney with no restrictions. If the MPD is closed 100% the draft is decreased, according to my manometer reading. If the air settings remain the same would the air entering the firebox remain the same or decrease due to the decreased draft of the MPD position?


Absolutely, It's the main bone of this whole perspective. Draft pressure dictates how much volume is entering the stove. Close the manual which weakens the negative pressure which means less volume thru the combustion air controls. :D

Limit air in by limiting air out...
Last edited by Lightning on Sun Dec 15, 2013 7:05 pm, edited 1 time in total.
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: Keepaeyeonit On: Sun Dec 15, 2013 5:59 pm

I would think that the air though the fire bed would decrease due in part to the exhaust being slowed or limited by the mpd.I may be wrong but I think its another tool to help control the burn but It requirers user input. Thats my perspective on them and like I said I'm not 100% sure because I never used one(I use a baro),so if I'm wrong someone set me straight :oops: .Keepaeyeonit
Keepaeyeonit
 
Hand Fed Coal Stove: Hitzer 983 insert
Coal Size/Type: Mammoth nut
Other Heating: oil furnace,and a crappy heat pump