metal Chimney Question

[[email protected]]

I have two wood stoves. One is on the third floor and uses simpson duravtech double wall insulated stainless chimney.
This chimney vents at the peak of the roof and is well above any part of the roof. This chimney has been in place
for three years.

The other stove is on the first floor and uses Selkirk Supervent insulated stainless chimney inside a chase
running through the second floor and enclosed knee wall space of the third floor. It penetrates the roof about 3 feet in from the eve.
Both chimneys draw fine.

The chimney servicing the first floor is only two months old. I am concerned about some discoloration on the outside of the chimney about 1 foot below the cap. A slightly bluish tint, like over heated metal. I have a thermometer on the single wall portion of the stack just above the stove which is always running between 250 or 350 with an occasional to rise 400/500. I have access to the chase and the insulated chimney sections are never uncomfortable to touch.

Could it be that the discoloration is coming from the exhaust gasses draping down the outside of the chimney?
The third floor chimney shows none of this discoloration.

 

[babalu87]

Mine is doing the same thing (Selkirk)

The chimney is designed to keep the heat inside the chimney
Once it comes out the top all bets are off so to speak and the gases are pretty hot up there, no worries thats what it is supposed to do
Part of me wants to get the ladder, some rags and a can of never dull and clean it up, then I remember I hate ladders

 

[mikedengineer]

My class A pipe shows the same thing and it is only 2 months old. It is 3 foot above the roof and less than 10 feet from the peak. There is 9 feet of class A. The hottest my single wass gets is 500-600. My single wall is also a heavier gauge than recomended and is one of those styles where one pipe goes into the other to make it adjustable. So at the point I measure from there is actually 2 sheets of steel. What ever that's worth.

-Mike

 

[elkimmeg]

this is a normal reaction, when heated smoke spills out into cold air, instant condensation and discoloration

 

[[email protected]]

The funny thing is my Simpson chimney which has been in use for three yaers is totally clean.