Manual Pipe Dampers - A Matter of Perspective

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: tcalo On: Sun Dec 15, 2013 6:08 pm

Lightning wrote:Close the manual which lowers the pressure which means less volume thru the combustion air controls. :D

Limit air in by limiting air out...


Does this mean the combustion air would decrease with the MPD closed, even with the air setting wide open? Technically it should...right?
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 7:03 pm

tcalo wrote:
Lightning wrote:Close the manual which lowers the pressure which means less volume thru the combustion air controls. :D

Limit air in by limiting air out...


Does this mean the combustion air would decrease with the MPD closed, even with the air setting wide open? Technically it should...right?


Yes, provided the air setting was wide open when the MPD was open.. Less negative pressure in the fire box means less combustion air entering the stove..
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: Lightning On: Sun Dec 15, 2013 7:08 pm

Keepaeyeonit wrote: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


I agree since air in is being limited by air out, and also agree that a baro has the same effect by weakening the negative pressure in the fire box. :D
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash


Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: rberq On: Sun Dec 15, 2013 7:40 pm

Lightning wrote: air in is being limited by air out

That's kind of half true. Under normal circumstances more gas volume goes out than comes in. Disconnect your stovepipe from the stove (please don't, really :D ) and the firebox will create its own draft, just like the can-style charcoal starter used for your barbeque. The stove will keep right on burning happily without a chimney as long as you keep the ashes clear. Chimney draft does two things: (1) provides adequate suction to remove products of combustion; and (2) if draft is more than "adequate", extra air is sucked into the stove to make the fire burn faster. Dampers of either type, MPD or baro, just reduce the influence of the chimney. It's OK if you reduce function (2) but it's deadly if you reduce function (1) too much. :cry:
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: Lightning On: Sun Dec 15, 2013 8:54 pm

I agree with all of that except the first sentence. :) if air can't get out, it can't get in. I believe the change in volume would only be due to the gases going out would be hotter and lighter thus taking up more space for their mass which is why they rise. .. :D

Hypothetically I believe you could extinguish a fire in the stove by completely blocking the flue even if the ash pan door were wide open, provided the rest of the stove sealed well.
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: rberq On: Sun Dec 15, 2013 10:50 pm

Lightning wrote:I believe the change in volume would only be due to the gases going out would be hotter and lighter thus taking up more space for their mass which is why they rise.

My bad. :cry: You are right. My thinking was that the molecules of carbon dioxide going out the flue (CO2) are heavier and therefore have more volume than the oxygen coming into the stove (O2). It is true that each molecule is heavier, but the gas volume is the same. (Except in the case of incomplete combustion, where each O2 molecule becomes two carbon monoxide (CO) molecules and the volume increases.)

Been a long time since high school chemistry, and it was counter-intuitive even then. :P

http://www.gutenberg.org/files/22657/22 ... uegas.html
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: Lightning On: Mon Dec 16, 2013 3:18 am

Wow, thanks for posting that link..
Some cool information in there 8-) :ugeek: :D
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: dustyashpan On: Sat Dec 21, 2013 1:58 pm

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

Kevin



problem. baro is oil burner boiler device, retrofitted to coal. when opened pulled cold basement cellar air up chimney. when designed cellars were not finished, many had dirt floor, stone foundation. no heat there to really lose. today baro in heated living room, basement finished den, pulls heated room air up chimney, wastes more heat than is saves.
dustyashpan
 
Hand Fed Coal Stove: Atlanta Homesteader, Harman
Baseburners & Antiques: Radiant Medal Dockash No.150 baseheater
Coal Size/Type: nut stove pea

Re: Manual Pipe Dampers - A Matter of Perspective

PostBy: Lightning On: Sat Dec 21, 2013 4:32 pm

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

Kevin



problem. baro is oil burner boiler device, retrofitted to coal. when opened pulled cold basement cellar air up chimney. when designed cellars were not finished, many had dirt floor, stone foundation. no heat there to really lose. today baro in heated living room, basement finished den, pulls heated room air up chimney, wastes more heat than is saves.


We went over all this nonsense in another thread. Barometric dampers do not waste more than they save.

Good luck telling the hundreds of people on here that use a barometric in their living room for years that they've been doing it all wrong :lol:

Usually the people that are dead set against a barometric haven't used one to see how beneficial it is to maintain a steady draft pressure.

Just for the record, Field Controls manufacturers a barometric damper specifically for oil and coal. :D
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash