Outside Combustion Air

gambler · Post by **gambler** » Wed. Oct. 31, 2007 2:08 pm

How many of you use outside combustion air for your stokers?

Matthaus · Post by **Matthaus** » Wed. Oct. 31, 2007 2:29 pm

Not yet, I bought all the pipe last year at the same time as the stove install. Still waiting to get the time, probably some time this winter it will go in!

stokerstove · Post by **stokerstove** » Wed. Oct. 31, 2007 4:13 pm

I use outside air for combustion. Last year was the first. I ran about 20' of 4" flexible hose from a window to the combustion blower and it worked well. This year I cut thru the siding above the stove, installed a hooded vent w/ a screen and I'm only using 10' of hose. Haven't started the stove yet to try it out....soon though!

spc · Post by **spc** » Wed. Oct. 31, 2007 4:43 pm

What is the advantage of using outside air for combustion?

LsFarm · Post by **LsFarm** » Wed. Oct. 31, 2007 4:51 pm

Hi spc. The air that is used for combustion and goes up the chimney has to come from somewhere. If the combustion fan pulls from the house without an outside vent, then the house is under a slight vacuum.

The slight vacuum pulls in cold outside air through cracks around doors, windows, foundations etc. This cold air mixes with the air in the house, cooling it and creating cold drafts.

If you have a newer or really tight house with good windows, sealed doors etc, then when the stove is running it has to pull pretty hard to get combustion air. If a bathroom vent fan, a clothes dryer or kitchen vent fan is turned on, then the combustion fan in the stove may not be able to provide enough air for the fire, or worse the airflow in the chimney may reverse, and fumes get into the house.

So when you provide a small duct from the outside to the inlet of the combustion fan, you provide a decicated source of outside air that does not cool the house, create drafts, or has to compete against other exhaust fans.

Hope this makes sense.

Greg L

spc · Post by **spc** » Wed. Oct. 31, 2007 5:12 pm

Thanks Greg, I have a LL Poineer on order & wonder if this will be needed? The room where the stove is go is a well insulated addition but the rest of the house has solid brick walls, 3 courses thick, but all the windows are double pane.

LsFarm · Post by **LsFarm** » Wed. Oct. 31, 2007 7:40 pm

I would guess that 99% of stoves do not use a dedicated outside air duct. But it is a nice thing to add to your stove installation if you have time and access to a place to put an outside vent. And a way to run a duct to behind the stove.

The biggest gain in my mind is the reduction of drafts in the house.

Greg L

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bksaun · Post by **bksaun** » Wed. Oct. 31, 2007 8:50 pm

I have used it With my Alaska Channing for 2 years now. Works fine, plus I am not sucking heated air out of my house. If I go outside and hold my hand over the intake, it is suprising how much air is actually moving through the pipe.

BK

gambler · Post by **gambler** » Wed. Oct. 31, 2007 9:56 pm

spc wrote:What is the advantage of using outside air for combustion?

As Greg stated it does not draw cold air into the house from all of the little cracks and openings but I also feel that it will create a better burn because as air gets colder and denser it holds more oxygen and as you give a fire more oxygen it gives a better more complete burn. Just a thought that I have and I don't have any proof that this is true.

JeepJunky · Post by **JeepJunky** » Thu. Nov. 01, 2007 12:02 pm

Any ideas on how to mount a inlet pipe to a Harman Magnum Stoker? My cumbustion fan has a small plate about half covering it. The service guy said that plate had somthing to do with the draft?? Can I remove that plate? If so I'm sre I could mount some type of flange.

Matthaus · Post by **Matthaus** » Thu. Nov. 01, 2007 12:05 pm

JeepJunky, don't remove the plate, you will over pressurize the stove.

I found a slick little flange at Lowes in the fireplace accessories section that will screw right into the sheet metal on the combustion fan. The flange can go over the plate. Just make sure you don't put any screws into the squirrel cage, could be kinda noisy!

Ed.A · Post by **Ed.A** » Fri. Nov. 02, 2007 7:19 am

bksaun wrote:I have used it With my Alaska Channing for 2 years now. Works fine, plus I am not sucking heated air out of my house. If I go outside and hold my hand over the intake, it is suprising how much air is actually moving through the pipe.

BK

BK, do you have pics of your set-up?
I have an air tube already in place, it's actually my old outlet for my exhaust fan in the dart room for when I used to smoke. I can just disconnect that hose ( 4" flex) and bring it 'round to the stove. I'm going to reverse the poliarty on the exhaust fan in place to blow hot air from the stove in the room now instead.

Any info would be great, thanks.

heatwithcoal · Post by **heatwithcoal** » Fri. Nov. 02, 2007 5:38 pm

I have my Magnum setup to outside air. I am sharing my house with a pellet stove upstairs and the magnum in the basement, both have fresh air. Both stoves burn bright and if you think about it, fire loves cold dense, oxygen rich air. Before I installed the fresh air inlet on the pellet stove I could feel cold air moving across the living room floor from the top of the basement stairs towards thepellet stove. I do not feel that anymore.
Also in the past I could smell a sulfur odor from my old coal stove until I installed the outside air inlet. I just went ahead an hooked up this inlet when I got the Magnum.

My wife is out with the camera now but I will post a picture when she gets back.

ginski · Post by **ginski** » Mon. Nov. 05, 2007 2:45 am

i also have had intentions of using outside combustion air for my mag since last season, but the job & kids put a damper on these projects.

since I already have 2" pvc running thru the wall behind the stove (which my propane furnace used to power vent), it should be a snap.

it's worth noting that when I removed the pvc cap from the outside line, cold air was rushing in thru the 2" pipe (the combustion blower was creating a negative pressure in the basement) as greg/lsfarm had mentioned. I unplugged the combustion blower for a couple of minutes and the air virtually died down to nothing coming thru the pipe from the outside. good insight/information greg!

perhaps thursday or Definitely friday i'll hook it up and tell you what my findings are.

tom

jimbo970 · Post by **jimbo970** » Mon. Nov. 05, 2007 8:06 pm

Hey Ginski ,

I would def like to know what you find out when you hook up to fresh air. I noticed from your pic, your stove is in a basement area with cinder walls. Are you ducting the stove to upstairs and if so how many outlets are you connecting to and distance. Last year I ran 1 6" duct to upstairs about 11' run. This year I move stove to other side of wall and want to run 2 ducts after coming off of a T using 6" then after T convert to 4" to upstairs. I am thinking that there should not be a problem doing this.

Any input before I do this from experience would be appreciated.

Jimbo

Outside Combustion Air

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