Hot Spot on Chimney

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ved0303

New Member
Nov 23, 2018
9
Iowa
Hey all, I am new to wood burning. We had a Jotul F600 installed a week ago, has about 18 feet from the top of the stove to the top of the chimney. I noticed today that the chimney has a spot, about 6 inches below the chimney cap and about 8 inches in diameter, that looks like it got hot. It has that rainbow discoloration that you sometimes see when metal gets hot. Seems to be on the downwind side of the pipe. I climbed up on the roof and that spot is definitely hotter than the rest but not so hot that you can't touch it. Is this normal? If not, what could cause this? Thanks. I am definitely a newbie.
 
I've gotten that on every polished stainless class A chimney I've ever installed - 5 installs so far. It looks like the heat discoloration that you'd get on chromed header pipe, but it's not. It goes away every year during the off season. Nothing to worry about.
 
Is this new or old chimney pipe and is this on class A chimney pipe?

A picture here would help so that we see what you are seeing.
 
Creosote deposits on the leeward side where the smoke will swirl. Maybe?
 
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This is quite normal in most cases . . . however I would hold off on trying to look for the pot of gold.
 
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We all get this on the new clean stainless steel. It's just the hot, dirty gasses swirling around as they exit the cap. It may come and go as the wind direction changes. The blue may become brown, then black as the deposit builds up. It's the hot gasses hitting the cold chimney. Keep an eye on the cap screen build up. They can plug up quickly. This will be much worse with wet wood.

But it's a non issue. Hows the new stove running?
 
Awesome thanks so much for all of he replies. I definitely feel better to hear that this is normal. I will post a picture as soon as I figure out how. So far the stove is running great! Heats the house very well and is very easy to light and keep running. Very happy!
 
Here is a picture.
 

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Yea just the the roof and the wind direction blowing the exhaust gas around the round chimney. I think to spot is a dead area where all the exhaust is directed to. On windy days and a smokey startup, I've watched mine do that.
 
Interesting. I have never seen this with our chimney pipe (DuraTech) or my neighbor's (Excel). Uneven insulation?
 
Mine (Ventis) will show that on whichever is the leeward side on a cold start, usually when it's below freezing. First rain or snow and it washes away.
 
Interesting. I have never seen this with our chimney pipe (DuraTech) or my neighbor's (Excel). Uneven insulation?

Hey! That's my setup too. I have duratech and he has excel. Never seen these spots either.

If it was me I'd get up there and check it out.
 
It may be fine, I've just not seen it happen before. Curious as to why?
 
My theory, backed up by obsevation, is that any air movement past the chimney creates a low pressure area on the downwind side of said chimney. Where said chimney stops, at the top edge, any air or gases present are sucked into the low pressure zone where any volatile compounds present may condense on the cool surface of said chimney exterior.
I may write my PhD thesis on this, please, please, no applause until it's peer reviewed.
 
I noticed the same kind of buildup when I changed from a cheap simple hat looking cap to the supervent "deluxe" cap. From the ground it looks like heat discoloration but if you get up close you can tell its soot.