Another draft question - trying to use 2 stoves

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abdickins

New Member
Hearth Supporter
Nov 21, 2006
4
I have done a search on the forum of the various draft problems and smoke in the house, etc. but I think I have a unique situation that may not have been covered yet.

Background info (sorry for the length):
I have two stoves. The first is an older Glacier Bay wood/coal insert that I use to burn coal. Located on the 1st floor, inside masonry chimney. I have a barometric damper and then 6 feet of stainless steel liner going into a chimney that has an 18"x18" flue. Height of the chimney is approx. 35 feet (3-story house). I initially hooked this up without the damper, and wasn't getting much heat out of it. I assumed most of the heat was headed up the chimney, hence the damper. It improved the heat considerably (stove top temp usually at 350), but I think I could still get a bit more. We live near some hills, and often get some substantial winds. The draft on this chimney is incredible. Wants to suck anything in sight and send it up the chimey (which doesn't have a cap on it at this time).

The house is rather large (5,000 SF total, about 2,200 on the first floor. We recently installed a 1979 VC Resolute becasue the heat off the Glacier Bay just wasn't enough. It's located in an addition on the first floor, about 20 feet from the Glacier Bay with open doorways between the 2 (no way to close off either area). Outlets out the back, 2 feet of single black pipe through the wall into a SuperVent chimney. Chimney is 15' high with a Vacu-stack cap to help because of the wind. It is about 10 feet above the addition roof, about 12 feet from the main building and is not enclosed. After some trial and error, we had used the stove with great success. Adequate draft, threw off the heat we were looking for, etc. Sometimes had a few problems getting a draft going becasue of the outside chimney, but all-in-all, we were happy.

Other info - no exhaust fans in use, door to 3rd floor closed, propane furnace located in attached garage.

The Vacu-Stack people claim that high winds will actually increase the draft, but they're pretty careful about each particular situation. I spent 30 minutes or so on the phone with their tech guy and gave him all of the info on usual wind direction, nearby trees, buildings etc. He said that their cap should help out.

Along comes a VERY windy day (30 MPH or more). The Glacier Bay is running with the air feed control about half open. I go to start a fire in the VC. Do the old small piece of paper in the opening to the stove pipe, light it and up it goes to the chimney. Seems like we have a good draft. Start the fire and smoke quickly fills the room. Air inlets are fully open, crack the front door open, open various windows nearby and even in the room with the Glacier Bay. Smoke continues to come in, although not as bad or continuously. More intermittent and it seems tied to the wind gusts. Had to give up the effort due to the smoke.

I believe that the problem stems from the overdraft on the Glacier Bay. This stove literally howls at times when the wind gets going. The air that is being pulled up that chimney has to come from somewhere, and I'm guessing that it's actually pulling it down the other chimney, even if other windows are open. The barometric damper controls the draft, but only in the sense that it draws room air into the pipe instead of through the stove - it still has to come from somewhere). I haven't tested it out, but I would guess that the VC stove would draw and burn just fine if the other stove/chimney was shut off completely.

I'm thinking of trying to add a "regular damper" to the stove pipe (before the barometric damper) to try to lessen the draft. Also maybe a chimney cap. Any other ideas of how I can get use out of BOTH of these stoves?

Thanks.
 
was the wind coming from the opposite side of the house? also with a single story addition that close to the taller building you will likely have draft issues with the flue, magnified when wind comes from opposite direction , over the roof and diving down on the lower chimney. 10 ft of exposed supervent outside aint helping either, lots of pipe to hold heat in, that is exposed outside. its been my experience that lower additions with chimneys through the lower roof which do not extend above the higher roof are prone to downdrafting , especially in windy conditions, couple that with that animal thats sucking air out of the house at a higher volume and bingo , serious downdrafting. its possible that outside combustion air if it can be coupled directly to the second unit with the weaker chimney will help , but its hard to say how much , particularly in the lighting stages when the shorter flue does not have any heat in it and the door may having been cracked to get the unit going. you may have to get an established fire in the second stove before lighting off the first one to overcome the negative pressure buildup caused by the first chimney when it picks up its "hot draw". gonna be a tough one to solve completely, but i hope this helps ya.
 
I'm guessing that the regular damper on the big stove will help, but probably ONLY if you disable the barometric damper when trying to get the second stove going. If you have the regular damper and the barometric going at the same time, I'd expect that you'd still have the same amount of air getting sucked up the chimney, but more would be going through the BD and less through the stove...

OTOH, you might get better heating if you shut off the BD and just regulate with a manual damper, but I'm not sure.

Gooserider
 
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