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[free heat]

I am wondering what the benefits are of running a triple or double walled insulated chimney on a outdoor boiler, versus just a plain single walled black stove pipe. I have noticed so many different types of chimneys being used, and nobody seems to has a good answer of why they chose that type of chimney to use. Let's hear what you are using and why you selected that type, thanks in advance.

[schoppy]

Actually there are several reasons/answers to your question. First of all, a class A chimney is required by code for wood burning appliances. Secondly to follow a manufacturers requirements (i.e. warranty) you need to use the chimney type they recommend as well as height and clearance requirements. Also, depending on the boiler you have, creosote build up would be terrible with an non-insulated chimney which increases the chance of a chimney fire. Lastly, if your boiler operates with atmospheric draft (no combustion blower either forced or induced) a single wall pipe can have an adverse effect on natural draft units. Bottom line-don't cut corners on your install and be safe.

My G400 Heatmaster uses 8" double wall insulated stainless steel vent pipe and I needed 2-36" sections added to the 18" section the unit comes with to get the proper height above my wood shed roof.       

[Pointblank]

Insulated chimney also helps reduce condensation that can form and run back into the stove when its idle. Water (condensation) combined with ashes or creosote creates an acid so the dryer you can keep these stoves, the longer they last.

[Chas]

I went with double wall insulated because that's what Slimjim suggested, and I would never second guess him.

[mlappin]

Go with the double wall stainless, won’t ever have to replace it for starters. Less creosote build up is another big reason.

On my homemade I actually had a piece of double walled non stainless pipe. Not sure what it was or for but it was free, rotted off at the base eventually one weekend and all I had was regular black stove pipe in 8” so I put that on, lots of extra condensation and built up a lot of creosote in short order, stove didn’t burn near as well, finally made it to Old Fort and bought a 4’ chunk of 8” stainless double wall pipe, was almost like a new stove again.

[slimjim]

Thanks for the kind praise Chas but believe me when I say that most of my knowledge has come from doing it the wrong way first!
 Another good reason for a double wall insulated pipe is to stop rainwater from getting into the ash in your boiler, think about this guys, if you use single wall, rainwater will hit the side of the pipe and travel down the side of the pipe right into the boiler, with double wall the rainwater travels down the side and drips off the drip edge of the pipe and onto the roof instead

[tinfoilhat2020]

i have 6ft of double wall stainless and a SS rain cap/spark arrestor on my heatmor. I used 12ft of black stove pipe on my old coventional natural draft unit years back and it went to crap in no time. Tons of creosote build up inside the pipe, i have to clean the stack every few weeks. what a pain! also lots of moisture getting back into the firebox! I spent the $180 on all the stainless stuff at menards as it was recommended by my dealer....twist and lock on! easy and will last for years!

[free heat]

Thanks everybody, The past two seasons I have used a single walled black stove pipe and really had good luck. I did have to seal up around the pipe like slim jim said with a hilti fireproof type of cement and it really held up well. I never really had any creosote problems because I only burn seasoned wood. I opted to buy a 3' double walled stainless pipe at menards with a separate adapter.