Chimney Life span

[KodiakII]

My new DT-M vent showed up last week. Quite different looking than the old DT...hope it holds up better.

[lightsison]

My vent pipe is showing signs of wear and I am on my forth season. If you burn to cold it will rot your pipe mine has pin holes in the hood and cap but none in the inside liner. My rot was due to condensation dripping from the hood onto the outside of the pipe
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Is this thing on

[SidecarFlip]

Interestingly, if you run your A/F ratio too lean, it's hard on internal componentry and if you run it too rich, it rots your venting because you can't achieve the vent temperature to prevent condensation.

Proper balance is achieved by balancing the vent temperature and the heat output without too high of firebox temperature.

The complexities of solid fuel.
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Flipmeisters Specialty Products, LLC
www.flipmeisters.com

[KodiakII]

I think with the design of the Selkirk DT pipe, and the long length of it that I run, it would be hard not to have cool exhaust temperatures. I have switched from 4 to 3 inch so hopefully this will warm things up a little.
As as a side note on a sort of related topic...a guy at work told me the other day that insurance companies were frowning on larger diameter chimney because it is harder to keep them hot and... reduce the build up of creosote.

[SidecarFlip]

Switching to 3 from 4 might be a problem overall. Reason is, the manufacturer calculates the pressure the draft fan can achieve for a certain length of vent. Exceeding that recommendation causes too much back pressure. Consequently, the draft fan can't expell exhaust products properly. That's why the need for 4" is mandated when you exceed the recommended vent length whether through straight vent or elbows. Remember, every elbow increases that resistance as well.

Thye vent design retains interior heat through a thermal break and insulation. Just because the vent don't 'feel' all that warm on the outside, don't mean the interior isn't at a temperature that precludes condensation.

The only place condensation (and the resultant corrosion) seems to be prevelant is at the vent cap end and that's where it's actually the coolest because one, it's the farthest away from the heat source and two, the cap is uninsulated and oftentimes exposed to rain, wind and snow, all temperature reducing factors.

Personally, I feel the benefits of 4" outweigh the negatives. For one, it allows a greater degree of byproduct buildup inside. The interior diameter is 33% greater than 3". It also flows better, especially on long runs which is why it's recommended in the first place.

I believe your friend is referring to masonry chimney applications rather than pre-fabricated. The larger the masonry chimney in interior dimension, the greater the exhaust gas temperature has to be and has to be maintained to prevent buildup. The key word there is creosote. Creosote isn't a factor in solid fuel burning like it is in raw wood stoves or coal furnaces.

The buildup you get with an appliance is fly ash, not creosote.

I'm not saying that you can't get creosote formation because you can, but only in a masonry chimney, not in a pre-fabricated, designed for solid fuel appliance vent.
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Flipmeisters Specialty Products, LLC
www.flipmeisters.com

[mustang00]

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Live from Dalhousie Station, Quebec, Canada

1989 Dovetec Corn Heater(was free)
...loving this heat...
..Not just another pretty face
Best lil loghouse north of the Border lol!!

[KodiakII]

My stove has three inch right out the back, and Selkirk designed the new system...so I hope I have gone in the right direction.

No my buddy was talking about prefab chimney not masonry.

[Mary B]

Has anyone tried putting a 6 inch piece over the top 3-4 feet and filling it with high temp foam insulation(They do make a fire rated version)? Seems it would keep the top warmer and slow the rate of corrosion.
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Never trust a skinny chef
Bixby 115
Outdoor wood fired BBQ pit

[Corny]

For the 3-storey tall outdoor chimney for our wood-burning cookstove in the kitchen, we inserted a stainless liner down the clay-lined chimney. The liner was wrapped on the outside with a white fibre insulation tied on with stainless wire. The insulation was hi-temp and purchased from a local fireplace and stove shop. This insulated liner improved the draft of the chimney greatly. It wasn't cheap, but definitely more economical than insulated pipe. Before the retrofit, we were subject to downdrafts whenever the wind switched to the SW.
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Bixby 115 MaxFire.
My motto: "If it doesn't fit, make it fit."
My mantra: It's in the WIKI!: http://forum.iburncorn.com/wiki/index.php/Bixby

[tallcorn]

I think a creosote exhaust fire in a corn burner is not possible. I doubt it could happen in pellet vent on a pellet stove burning wood pellets, either. Wood pellets are low moisture and the air/fuel ration is such that combustible creosote shouldn't form in the exhaust pipe near the stove and the way pellet burners work the stove shouldn't emit exhaust that could ignite creosote even if it did form in the pipe. I think creosote fires in fireplace and wood stove chimneys happen when they are over fired and the flame reaches the creosote in the chimney and (big and) the air supply is poorly or not restricted. It would be interesting if there were any known record of a creosote fire in pellet vent on a pellet type stove.
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Countryside 3500P (pedestal version) used 8-9 yrs, 24/7 during days requiring heat. All original motors. Burns moldy corn, and pellets equally well. Burn it if you got it.

[KodiakII]

My three inch is running fine on all settings, I actually had to turn the draft down quite a bit from it's old four inch setting. Will just have to wait and see how the dt-m holds up to the rigors of corn burning...will keep everyone posted!