Chinook 30.2 backpuffing into room

[Jhelmick]

Hello,

It’s my second full season burning a new Chinook 30.2. The stove has had about 2.5-3 cords through it. I noticed this last year as well.
My chimney was just cleaned last month. I always burn kiln dried wood and I’m extra happy with our wood this year. The stove is connected to an outside air kit. I should add that I have double wall stove pipe up about 2 ft with two 45s and a 90 into class A chimney pipe which is about 22ft high inside a framed chase.
I notice the problem when burning on low, especially if I’ve recently turned the stove down. I also notice it in the middle of the night some. I’ll get sudden ignition of the gasses and then I’ll get pretty strong smoke odor in the room. It doesn’t seem to happen every time I burn on low, but it’s relatively frequent. Typically the cat thermometer is at 2 o’clock or higher. I know BKs had an issue with smoke smell previously but I thought that was resolved well before I purchased my stove in 2023. Any thoughts are appreciated.

 

[Dieselhead]

I’ve had that happen a few times, most cat stoves are susceptible to it. The cat is working great, upper active range the wood is off gassing quicker than the cat can process it and it ignites the smoke in the firebox. The exhaust area can’t handle the volume completely and the stove burps a little smoke from wherever it can. Even the intake side. Smoke explosion would be the semi technical term.

 

[stoveliker]

This is not the much discussed smoke smell as that was from a door gasket or so, not back puffing.

Do you know your flue temp? I think you may be burning a bit too low, leading to lower flue temps, leading to less draft, leading to gases building up and eventually sometimes suddenly igniting and pushing out through some seams (of the pipe?).

 

[Murray01]

Is this the same as flames appearing then disappearing only to reappear and disappear? Seems like the flames are concentrated on the top front of the stove below the CAT.

 

[stoveliker]

It can but does not need to be.

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And it explodes so strong that the gases can't exit via the flue fast enough, smoke gets pushed through the seams of the door or flue. That is backpuffing.

Just such flames that are on and off without smoke coming out is not (yet, sometimes) backpuffing.

 

[stoveliker]

This is a good video of backpuffing

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[Murray01]

Thanks, similar to what my stove is doing only not as violent as the video. No smoke leakage. BK Princess