Cold Stove Back Draft Issue

[Parallax982]

My wife and I have a Pacific Energy Anderlea T5 stove. The stove pipe is double wall. Last year, when we replaced our old stove, we had to fix a water leak in the pipe. A technician replaced the cap, which was apparently the problem. He also reduced the pipe length by one section, as the draft was a bit too much for this stove. Now, when the stove is cold, we sometimes get a smoke smell in the house.

We've been careful to crack a window in a bathroom when running a fan and it happens even when no fans are running. Most often, we notice it first thing in the morning. Then it dissipates during the day. So it seems to be related to the cooler temperatures that night brings. Rainy days may make it more likely too but I'm not 100 percent sure of that, as there hasn't been much rain since this issue began. It seems to be worse right now, in the warm season.

One of the things the tech did when he replaced the cap was he taped closed some air vents in the pipe right near the roof line. The vents are covered by a sort of visor. He covered them just to be sure water wasn't getting in there. I'm wondering if those openings might be needed to prevent air from flowing back down the pipe under certain conditions. Or maybe it's unrelated and we just have the wrong cap.

I've posted some photos of the stove pipe and the area near the roof line. I appreciate feedback from anyone who has experience with this issue.

 

[Whitenuckler]

I'm surprised someone can make it shorter if it met code.

 

[Parallax982]

I'm surprised someone can make it shorter if it met code.

It originally met code at this height and then was lengthened. So now it's back to the original height.

 

[begreen]

Based on similar issues with previous stove on the same flue, I suspect that the problem may have to do with the local topography or negative pressure in the stove room.

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[Parallax982]

Based on similar issues with previous stove on the same flue, I suspect that the problem may have to do with the local topography or negative pressure in the stove room.

A non-commercial service in support of responsible home heating with wood - How Wind Affects Chimney Performance

The Wood Heat Organization was formed to support the public in the responsible use of wood energy in the home. We fulfill our mandate by providing reliable information, by conducting research into wood heating-related issues and by representing the public interest in discussions of policies that...

woodheat.org

Is it possible to buy a section of selkirk pipe that has a flue or something that attaches to it with a flue. If I could close it off, it might solve the problem.

 

[Whitenuckler]

I had a condo once on Lake Huron, and the building had wood fireplaces, and it was hit and miss if you were
going to get smoked out. It could change anytime, even hours after the fire was going (masonry open fire).
I did notice they had some special directional moving cap. I gather it keeps the opening downwind. That might
be an easy thing to try.

 

[begreen]

Is it possible to buy a section of selkirk pipe that has a flue or something that attaches to it with a flue. If I could close it off, it might solve the problem.

Do you mean damper? Is the existing stove pipe Selkirk or Duravent?

 

[begreen]

This inquiry has been covered in the previous thread on this topic. Stove has an OAK. Link here for more background info.

P

Thread 'Cold Stove, Wood Smoke Leaking into Home'

Dec 3, 2024

I have a Pacific Energy Anderlea T5, brand new. We've used it a number of times. Really happy with its performance.

It's for use when the electricity is out and when the temperature outside drops too low for our heat pump. So it's been sitting for the last two or three weeks. One day, my wife said she smelled smoke. It turned out that some ash sitting on the lip of the stove, just under the door, was the culprit. I cleaned that up and the smell went away. Then last night, again with the stove not used in weeks, I smelled it again. This time the only ash was inside the stove. This...

• Parallax982
• Replies: 81
• Forum: The Hearth Room - Wood Stoves and Fireplaces

 

[Parallax982]

Do you mean damper? Is the existing stove pipe Selkirk or Duravent?

Selkirk

 

[Parallax982]

This inquiry has been covered in the previous thread on this topic. Stove has an OAK. Link here for more background info.

P

Thread 'Cold Stove, Wood Smoke Leaking into Home'

Dec 3, 2024

I have a Pacific Energy Anderlea T5, brand new. We've used it a number of times. Really happy with its performance.

It's for use when the electricity is out and when the temperature outside drops too low for our heat pump. So it's been sitting for the last two or three weeks. One day, my wife said she smelled smoke. It turned out that some ash sitting on the lip of the stove, just under the door, was the culprit. I cleaned that up and the smell went away. Then last night, again with the stove not used in weeks, I smelled it again. This time the only ash was inside the stove. This...

• Parallax982
• Replies: 81
• Forum: The Hearth Room - Wood Stoves and Fireplaces

Be sure that the smoke smell is not from outside. The air quality yesterday in the San Juans and Bellingham wasn't great due to wildfire smoke in the Olympics.

I had started that thread too but it didn't lead to any solutions. It caused me to test extensively, making sure exhaust fans weren't causing the problem. But i still have no fix. I'm hoping there's an option to block the backflow. You mentioned the term "damper". I think of that as a way of slowing the airflow. I'm wondering if there's a way to block the exhaust pipe entirely once the stove is good and cold, and there's no possibility of carbon monoxide coming into the home.

 

[begreen]

What would generate this gas? A car idling outside? It's very unlikely that any carbon monoxide is coming into the house from the flue system with a stone cold stove.

Be sure that the smoke smell is not from outside. The air quality yesterday in the San Juans and Bellingham wasn't great due to wildfire smoke in the Olympics.

 

[begreen]

Selkirk

 

[Parallax982]

What would generate this gas? A car idling outside? It's very unlikely that any carbon monoxide is coming into the house from the flue system with a stone cold stove.

Be sure that the smoke smell is not from outside. The air quality yesterday in the San Juans and Bellingham wasn't great due to wildfire smoke in the Olympics.

That's a good point. It's not because we open the windows to get the smell out and it works. But it's something to keep in mind.

My reference to CO poisoning was with regard to running the stove and then waiting a sufficient time to close the pipe so as to avoid asphyxiating ourselves.

 

[Parallax982]

View attachment 339711

Do you think this might solve our problem? It would still be 20 percent open. What do you think?

 

[blades]

Only way to stop a back draft is to completely close off the flue when not using stove. The damper above will not do that. If you have the stove hooked up with an OAK it is possible that may be contributing or is the cause. As was mentioned above a negative pressure in the home envelope would be cause, the various exhaust fans which sometimes do not have a fully closing damper when not in use is another possibility. If you have an air exchange system it might not be balanced correctly which could cause this as well. Some of those, from days past, when not in use, still had an ambient air flow due to no damper in the intake. Wood stoves are not a totally sealed system unlike current furnaces

 

[Parallax982]

Only way to stop a back draft is to completely close off the flue when not using stove. The damper above will not do that. If you have the stove hooked up with an OAK it is possible that may be contributing or is the cause. As was mentioned above a negative pressure in the home envelope would be cause, the various exhaust fans which sometimes do not have a fully closing damper when not in use is another possibility. If you have an air exchange system it might not be balanced correctly which could cause this as well. Some of those, from days past, when not in use, still had an ambient air flow due to no damper in the intake. Wood stoves are not a totally sealed system unlike current furnaces

I do have an OAK. I've tested it by covering it as best as possible and it made no difference. Do you know of a way to easily close off the flue when the stove is not in use? I could try stuffing some newspaper up there and see if that makes a difference. Just have to remember to pull it out before lighting the stove.

 

[Whitenuckler]

I do have an OAK. I've tested it by covering it as best as possible and it made no difference. Do you know of a way to easily close off the flue when the stove is not in use? I could try stuffing some newspaper up there and see if that makes a difference. Just have to remember to pull it out before lighting the stove.

If you have OAK, and the stove is air tight, I would think whatever air flowing in or out of the stove should stay in the stove pipes. Is there a flapper in the OAK ? My pellet stove has one, but of course it has a combustion blower.

 

[Parallax982]

If you have OAK, and the stove is air tight, I would think whatever air flowing in or out of the stove should stay in the stove pipes. Is there a flapper in the OAK ? My pellet stove has one, but of course it has a combustion blower.

No, there's no flapper in the OAK. It's just a pipe through the wall. I don't think these stoves are air tight. The stove pipe isn't airtight either. Tight enough to prevent smoke from coming into the house when a fire is burning but there are no seals and there's no way to prevent air from leaking through.

 

[begreen]

If you have OAK, and the stove is air tight, I would think whatever air flowing in or out of the stove should stay in the stove pipes. Is there a flapper in the OAK ? My pellet stove has one, but of course it has a combustion blower.

I don't think any modern stove is air tight.