adding secondary burn tubes to wood furnace

[j7art2]

I've been doing some research on retrofitting my dinosaur 40 year old wood furnace to make it more efficient as I've already gone through around 6 cord this year. It's on it's last legs anyway, and would probably not get more than another 5 years out of it before needing replacement (this gives me 5 years to save money. lol). Just a guess, but who knows, I may be able to squeeze out more.

I've seen a few people do this successfully, and I was wondering if any of you are still using your systems years later, how they are holding up. My concern of course, is damaging the structural integrity of the furnace, and it's longevity with the mod installed.

 

[Smoke Signals]

Sorry I can't help you but I will be watching with great interest!

 

[newyorker]

Go on you tube their is a guy that did it to a Englander with great results I emailed him and talked to him real nice guy

 

[laynes69]

Personally, I wouldn't put that kind of stress on a 40 year old furnace. There was a user on here that modified his hotblast wood furnace with a secondary burn system. He did notice a drop in wood consumption and more heat, but all that was short lived. He said within a year or so, the furnace developed cracking from the high temperatures. He replaced the modified furnace with a Tundra and the last time I heard from him, he was very happy. Longer burns, less wood. If you look at the design of a modern wood furnace, they contain fully lined fireboxes, insulated baffles and preheated secondary air. It's not that you can't retrofit your furnace, it's the heat generated from the burns may cause premature failure of the steel.

 

[warno]

Sorry to possibly high jack the thread here, but do secondary burn tubes work in a fully water jacketed fire box? Do they burn off gases properly?

 

[brenndatomu]

No, you can't get temps high enough to make it work