Draft out of control in high winds

[dauntless89]

I've tried to research this on my own and haven't found anything helpful. Like the title says, my draft is out of control on windy days. We live on a flat plain in the high desert of southern Utah. There are no trees, hills, or mountains for miles. If the wind is blowing at all, it's 40+ sustained. At least.

The stove is a Pacific Energy Neo 1.6. Pipe is double-walled and runs straight up 12 or 15 feet, the cap is well above the roof peak in our double-wide manufactured home. When there is no wind, the draft is excellent and once a fire is established, you have to work at it to keep the temperature in the living area below 80. It's not too hard to set the stove up for an overnight burn and have a strong enough coal bed in the morning to just toss regular logs on.

When the wind blows, you can't turn the stove down enough to get an overnight load of wood to last more than about 4 hours. There is a flue damper (the Duravent one with the holes in the plate) and it isn't enough. One time last winter, on a windy night, I botched an overnight loading and lost control of it. Not sure if it was a legit chimney fire or if I just allowed the entire load to ignite prematurely due to bad door technique, but the secondary burn shelf was glowing red and I ended up having to block all the air inlet ports with wet rags and manually unload the stove. I adjusted my loading strategy and had a similar event happen again (caught it soon enough that the wet rags were enough, didn't have to unload it) and now I'm paranoid about burning overnight and on windy days. This sucks because my electric furnace costs over a dollar an hour to run.

I've considered modifying the existing damper to block some of the holes so it can be more effective in the closed position. I've looked into and ruled out a barometric damper. I thought about building some kind of baffle around the pipe cap to mitigate the wind. Then, I found out about wind-resistant chimney caps (like the Vacu-Stack), but based on the descriptions, they seem to be designed for the exact set of terrain and wind-related draft problems I don't have. Being surrounded by literally nothing, the wind is always parallel with the ground and we don't have any issues with backdraft or backpuffing, just Ma Nature sucking on that straw like she's me tearing into a chocolate malt. Developing extra venturi, as the Vacu-Stack literature describes, is exactly what I don't need. I need something that neutralizes wind's effect on the stovepipe. Can anyone elucidate on the Vacu-Stack or throw me a bone on something else?

Thanks,
Tony

 

[bholler]

I've tried to research this on my own and haven't found anything helpful. Like the title says, my draft is out of control on windy days. We live on a flat plain in the high desert of southern Utah. There are no trees, hills, or mountains for miles. If the wind is blowing at all, it's 40+ sustained. At least.

The stove is a Pacific Energy Neo 1.6. Pipe is double-walled and runs straight up 12 or 15 feet, the cap is well above the roof peak in our double-wide manufactured home. When there is no wind, the draft is excellent and once a fire is established, you have to work at it to keep the temperature in the living area below 80. It's not too hard to set the stove up for an overnight burn and have a strong enough coal bed in the morning to just toss regular logs on.

When the wind blows, you can't turn the stove down enough to get an overnight load of wood to last more than about 4 hours. There is a flue damper (the Duravent one with the holes in the plate) and it isn't enough. One time last winter, on a windy night, I botched an overnight loading and lost control of it. Not sure if it was a legit chimney fire or if I just allowed the entire load to ignite prematurely due to bad door technique, but the secondary burn shelf was glowing red and I ended up having to block all the air inlet ports with wet rags and manually unload the stove. I adjusted my loading strategy and had a similar event happen again (caught it soon enough that the wet rags were enough, didn't have to unload it) and now I'm paranoid about burning overnight and on windy days. This sucks because my electric furnace costs over a dollar an hour to run.

I've considered modifying the existing damper to block some of the holes so it can be more effective in the closed position. I've looked into and ruled out a barometric damper. I thought about building some kind of baffle around the pipe cap to mitigate the wind. Then, I found out about wind-resistant chimney caps (like the Vacu-Stack), but based on the descriptions, they seem to be designed for the exact set of terrain and wind-related draft problems I don't have. Being surrounded by literally nothing, the wind is always parallel with the ground and we don't have any issues with backdraft or backpuffing, just Ma Nature sucking on that straw like she's me tearing into a chocolate malt. Developing extra venturi, as the Vacu-Stack literature describes, is exactly what I don't need. I need something that neutralizes wind's effect on the stovepipe. Can anyone elucidate on the Vacu-Stack or throw me a bone on something else?

Thanks,
Tony

The vacustack would do the opposite of what you want. There are lots of caps with wind bands I would try. You can also double up your damper

 

[Highbeam]

Two key dampers. Something more permanent on the intakes like metal tape. Larger splits, stacked tightly.

 

[dauntless89]

Thanks fellas. I think I'll start with taping up some inlet ports as well as looking into different caps with wind bands. I'd have to go look but I don't believe mine has one.

Question on that, the adjustment at the front controls air for the door wash and an inlet port at the bottom/front of the firebox. There is a smaller fixed port, and one the adjustment lever acts on. At the back of the firebox, behind the cleanout tray, there's a separate inlet for the secondary burn stage, this one has four fixed port and a weighted door which opens and closes depending on draft.

I'm thinking it would be better to block some or all of the fixed secondary ports as under most conditions, the adjustable door will just be more open than it would be if the ports weren't blocked. It would also theoretically make the second stage less efficient when the fire's active enough to open the door all the way, this would result in potentially more soot buildup in the chimney under these conditions, but it would also be somewhat safer as there's less fresh air entering the stove late in the combustion path. These fixed ports in the back are also the most difficult ones to block if it were to run away on me again.

 

[Highbeam]

Your stove is one of the few that actually has some method of varying the secondary air with that weighted flap deal. Most, like mine, have wide open secondary air all the time.

The secondary air is injected above the fire so shouldn’t accelerate combustion as much as the primary air intakes.

I also worry that some of that secondary air acts to cool the secondary manifold system so limiting it might melt the secondary system.

So, I would recommend first gaining control of the primary air and then seeing how that goes.

 

[begreen]

I hate publicly commenting on this stuff because then everyone thinks it has to be done to their stove too. This is a unique situation and there are some remedies to try. Highbeam is correct. Start with the primary and boost air. I will PM you with details.