Stove Pipe crroding from the inside

[Kelly James]

I installed a new Blaze King wood stove back in October and have discovered that stove pipe is rusting from the inside. I just removed the pipe and was able to crush it with my hands it was so corroded. It connects to a stainless steel pipe that runs up an large old chimney. There was a wood stove in this location for about 40 years that never had any issues at all. The stove has been in almost constant use and the wood is well seasoned although I live in Oregon so there is always going to be some residual moisture in the wood. I got a new piece of pipe on warranty from the supplier. We are all baffled as to what caused this, and I am wondering if I should use a piece of stainless instead of steel.
Any help or advice would be greatly appreciated,
KJ

 

[begreen]

If firewood is dried properly, its moisture content will be below 20% even in western OR.

 

[peakbagger]

Any chance you are burning driftwood or wood that has been in salt water?. That can rot out a stack and stove.

The other possible source of stack corrosion is burning trash.

 

[begreen]

How old is the stovepipe? Double-wall stove pipe has a stainless liner. It is definitely better for a BK stove.

 

[Kelly James]

That's what I figured. The wood I'm burning is from maple trees that were killed in the big fire we had in this area several years ago. It is really well seasoned and hard a a bowling pin. We burn no trash or driftwood. The pipe was new in October.

 

[begreen]

That's really unusual, even for cheap stovepipe.

 

[Kelly James]

I agree!! Could this be caused by rain coming down the pipe? I did put a new cap on the top and I did not caulk it because it seemed like a really tight fit.?
KJ

 

[begreen]

Possibly. Do you live close to the coast? That might add salt spray to the rain. Add heat and there will be accelerated corrosion.

 

[Highbeam]

Because the inside of your stove is also corroded all to heck it’s not the pipe’s fault.

It looks like water intrusion. Water washing down the pipe mixes with byproducts of combustion to make a highly corrosive liquid. The single wall pipe is thin mild steel and won’t last long. Your stove can be compromised too.

Seal the chimney. Water is getting in.

Second option for the cause is that your wood is so wet and flue so cold that the steam is condensing and running back down into the stove. If this is the issue then burn sun 20% wood at a high enough temperature that you don’t see the smoke/steam flume attached to the chimney cap.

 

[Highbeam]

Rereading your OP, you have a large tall old chimney with a stainless pipe running up it. How tall and is the stainless pipe insulated?

 

[Kelly James]

HIghbeam
Thanks for your response. The pipe is not insulated and runs about 20ft up through the chimney. Your comments make sense to me, are you thinking that there might also be condensation because of the length of the pipe. There is a large cap on top of the chimney, I'm wondering if there is some leakage at the point where the pipe goes through it.
KJ

 

[Kelly James]

Also any thoughts about what I should do to the inside of the stove before I put in a new pipe???
KJ

 

[Kelly James]

The pipe is not insulated

 

[begreen]

Also any thoughts about what I should do to the inside of the stove before I put in a new pipe???

Not much can be done other than stopping any future water intrusion.

Can you post a picture of the chimney top so that we can see how it's capped?

 

[Kelly James]

Here is my chimney, the black stuff on the cap is hi temp caulk I put on yesterday to seal it all up.Those joints were not caulked before. I scraped out the interior of the stove as best as I could to remove the rust and treated it with naval jelly, washed that out and put it back together. Running the fire without engaging the combustor for now. I'm open to redoing this all if need be. Your advice is greatly appreciated.
KJ

 

[begreen]

Sealing the upper-edge of the storm collar is essential. If that was not sealed then water could run down the side of the liner and eventually to the stove. Hopefully, that is all over now. Was black RTV silicone used?

 

[moresnow]

If you're running in the active zone, close your bypass.
Not recommend to run hot without being closed properly.

 

[Kelly James]

Thank you all for your advice. I did use Hi temp silicon, rated to 500 F. Hopefully that will do the trick. Also going to closely monitor the moisture of my wood just incase.
Thanks again,
KJ

 

[EatenByLimestone]

How about fire fighting chemicals that might have been dropped to put some of the fire out?

 

[Kelly James]

Thanks for your post, No chemicals were used to fight the fire in this area, It happened too fast.
KJ