Coalpail.com Forum

mozz wrote:How much coal is wasted per day through a barometric damper? Exactly the same amount of unburnt coal you can pick out of the ashes.
Put your baro on the floor and pipe it up to the thimble. Drawing colder floor air thus saves you money!

I find this interesting and it makes sense in two ways. First, it uses the cold infiltrating air AND since colder air is drawn in the baro, it would need less of it to do its limiting job.

Keepaeyeonit wrote:Mr Carbon 12,where there's a will

IMG_2463.JPG

there's a way .Keepaeyeonit

@KEOI... thats pretty damb impressive sir! some tight quarters in their is their a blower fan inside that firebox? was that vent door even on that stove originally for the purposes of adding a baro? or is that your own "add-on"?

Hey Larry, on another note, with all the air turn over that is recommended it makes me question if a dedicated pipe to the outside is really necessary for combustion air.

Lightning wrote:Hey Larry, on another note, with all the air turn over that is recommended it makes me question if a dedicated pipe to the outside is really necessary for combustion air.

It is definitely required for a stove (furnace/boiler) that is in a confined space. For other areas it may or may not be required (as Sting would classically say, it depends).

If you don't have a confined space situation, you may find this to be interesting reading: http://woodheat.org/the-outdoor-air-myth-exposed.html

Thank you, I will look at that.

Lightning wrote:Hey Larry, on another note, with all the air turn over that is recommended it makes me question if a dedicated pipe to the outside is really necessary for combustion air.

Outside air is going to come in one way or another. Your house doesn't like a vacuum. The point is to manage where it comes in. Do you want it coming in around every crack, door, window and exhaust fan or would you rather control where it enters and direct it to the combustion appliance where it can be used as combustion air and then exhausted.

coalkirk wrote:

Lightning wrote:Hey Larry, on another note, with all the air turn over that is recommended it makes me question if a dedicated pipe to the outside is really necessary for combustion air.

Outside air is going to come in one way or another. Your house doesn't like a vacuum. The point is to manage where it comes in. Do you want it coming in around every crack, door, window and exhaust fan or would you rather control where it enters and direct it to the combustion appliance where it can be used as combustion air and then exhausted.

Good point Coalkirk, my make up air is at the other end of the house and the floor is like a wind tunnel all the way to the stove,I was going to put a intake on the North and South side by the stove but I use the furnace ducts to move air so I would not stop the draft it would just be warmer air.I don't know how much air is needed for combustion,the convection fans,and the baro but it seems like a lot.
Dcrane,thats my own add-on it was just a insert when I got it.I put the pipe together and wedged it up with the stove out,slid the stove in hooked up the pipe,and I used a cleaning rod to stuff insulation around the pipe where it enters the clay but its not to hard. Keepaeyeonit

Larry and Coal Kirk, good information

Keep an eye, convection fan shouldn't need any outside air since it should be recirculating air in the house.

Lee, I know I was referring to the air moving across the floor(basically controlling the air flow ) and since I draw air through the furnace ducts and back to the stove it travels across the floor ,yes you are right convection just moves the air it doesn't use the air .Keepaeyeonit

So,....if a Baro does not, in fact, use more coal or chill the house, is there really any down side to using them in most coal burning applications? It appears the positives outweigh the negatives,.....whatever the negatives might be

Carbon12 wrote:So,....if a Baro does not, in fact, use more coal or chill the house, is there really any down side to using them in most coal burning applications? It appears the positives outweigh the negatives,.....whatever the negatives might be

I got nothin

lsayre wrote:

Lightning wrote:Hey Larry, on another note, with all the air turn over that is recommended it makes me question if a dedicated pipe to the outside is really necessary for combustion air.

It is definitely required for a stove (furnace/boiler) that is in a confined space. For other areas it may or may not be required (as Sting would classically say, it depends).

If you don't have a confined space situation, you may find this to be interesting reading: http://woodheat.org/the-outdoor-air-myth-exposed.html

That link reads like it is written by someone with no hands on experience.
there are many posts in the forum concerning opening a window or outside door to establish draft when the stack effect of the house is stronger than the draw of the chimney. An outside air supply would modify that effect and the adverse effects of exhaust fans and other heating appiances.

bksaun wrote:It breaks the draft or if you will, It stops excessive draft from pulling through the stove, thus its saving fuel, not wasting it...

I fully endorse this view.

coalkirk wrote:..we have to rely on a barometric damper [that] can adjust automatically. I know my boiler uses less coal with a baro and my stack temps are lower.

This is certainly true.

The MPD and barometric damper accomplish the same thing through different means: A MPD reduces the flow of hot gases directly. When partially blocking the pipe, a pressure drop occurs across the damper and flow is reduced, and in turn the pressure at the stove exit is reduced.

The barometric damper reduces flow by cooling the temperature at the bottom of the chimney. This reduces the top-to-bottom chimney temperature difference, i.e. the driving force of the chimney itself. This reduces excessive pressure and consequently the flow.

Naively, folks look at a partially open baro door and conclude that they are wasting the heat of 75F room air going up the chimney. The fact is they are trading the room temp gas for about the same amount of hot, say 300F gas going up the chimney.

Besides a slight energy saving (about 5-8% on an excessive draft day), a barometric damper has a much more important purpose: By automatically reducing excessive draft, a barometric damper prevents hopper fires. This is true for chimneys as well as motor vented stoves.

Thank you.

So Larry did a fine job of answering the million dollar question of how much room air goes up the chimney thru the barometric compares to average air infiltration of a house. It seems a low percentage.

Now for the two million dollar question which I must agree would be based mostly on speculation. Ready? lol

Does the barometric ADD air infiltration into the home OR would the additional air passing thru the barometric slow down air that's leaving the house up above it? Which would keep overall air infiltration the same.

In other words, would it lower the neutral pressure plane (due to stack effect of the house) or would it raise it? Given that the house is equally sealed on top and bottom.