Chimney extension?

[hyperion]

We are still struggling with our VC Defiant's horizontal mode, the details were discussed in this thread:
https://www.hearth.com/econtent/index.php/forums/viewthread/51794/

After trying every which way, the horizontal is still inconsistent at best, and works about 20% of time with no apparent change of other variables. We are now thinking maybe our flue/chimney height is the problem. The flue goes straight up through the roof and floor to ceiling is 9' (this includes the stove which is 32" high itself). There are 3 more feet on top of the roof, for a combined height of 12' (I don't know how much thickness there is between the ceiling and the roof, but I am sure it's negligible), which I understand is very marginal to below requirement. On the other hand, the chimney APPEARS to draft fine and I don't really have any smoke problems.

Should we spring for a chimney extension? And if so, how many feet in addition, and how much will it cost (ball-park number)?

 

[begreen]

So there is about 10' of actual flue on the stove? I'm not surprised it's temperamental. 16 ft is the recommended minimum according to the manual for the Defiant. The cost would depend on the brand and size of pipe. It will also need a brace.

 

[hyperion]

So there is about 10' of actual flue on the stove? I'm not surprised it's temperamental.

Yes, there's no room for more flue inside the house, which I imagine is a common problem for ranch-style houses?

16 ft is the recommended minimum according to the manual for the Defiant. The cost would depend on the brand and size of pipe. It will also need a brace.

So I need 3-4 more feet. Say we go with the best brand (and which one is that?), and 8" pipes which I believe are what we have right now, what would be a ball-park number, with installation cost?

 

[begreen]

Say maybe 5-6ft more needed and a roof brace. The class A pipe has to be the same brand pipe as what is currently installed in order to mate with it correctly. Do you know what that is?

 

[hyperion]

I have no idea. It will have to be a company that was in business in 1980, when the house was built and the VC Defiant was put in by the previous owner. Is there anyway to find out, i.e. markings on the existing pipes?

 

[begreen]

Yes, if you are lucky there will be a label on the side of the ceiling support box or a stamped ID on the pipe. Take photos and post if possible. We may be able to ID it. However, the odds of matching pipe of that age are not so good.