convert leaking boiler to forced air

[tucker33]

Anybody ever turn an old leaking wood boiler into a forced air furnace?

 

[E Yoder]

I would be very hesitant to try that as a boiler is designed to have to the tempering effect of the water. Without that you could have warping, cracking, etc. which in turn could leak combustion gasses into your house.
But that's a guess without knowing more about the particular model.

 

[maple1]

Seems to me if it leaks, it will leak nasties to where they aren't supposed to be?

 

[DoubleB]

I'd also imagine you'd burn through a whole lot of wood, and/or wouldn't get much heat output, since heat transfer with air isn't nearly as good as with water.

 

[tucker33]

I would be very hesitant to try that as a boiler is designed to have to the tempering effect of the water. Without that you could have warping, cracking, etc. which in turn could leak combustion gasses into your house.
But that's a guess without knowing more about the particular model.

 

[tucker33]

Few thoughts . I was thinking of setting up like a forced air furnace not burning as hard as the boiler would. I agree one would need to be selective on what brand to try it on. Some of the boiler fireboxes are made with thicker steel than forced air furnaces. Would not consider using stainless steel since it's harder to weld. I see lots of boilers for sale with leaking tanks, thats leaking on the ground not into the firebox. So no nastys going into the building.
After reading many reviews on boilers I've come to the conclusion they come in two types those that are leaking and those that will be leaking. What I see is people who have them for a few years love them, but very few who have them for over seven years or so are so thrilled. There are exceptions. I have been running a AquaTherm since 1999. Bought it because it had a closed system that was supposed to last, and because it has only 76 gallon tank making it affordable to run with anti freeze. It has been ok thats how I would rate it does somethings well, others not so good. I made it 10 years before it developed a leak. As for forced air using more wood, can't really see one using more wood than my 345 Aqua Therm. she is a hungry beast.

 

[E Yoder]

What I meant by my post was that by taking the water away from the firebox the temps would go from perhaps 180 F to potentially over 1,000 F, even with a slow burn. If the tank isn't designed to flex and take that expansion it can buckle.
Not saying you can't make it work- just that there are sometimes years of testing by really experienced guys going into a particular stove. Be prepared to do a lot of tweaking and repairs. It's very hard to predict what things you might run into.
And who knows it might work?
A boiler should last 20+ years if maintained properly.

 

[maple1]

Usually boiler leaks come from condensing creosote - which happens inside the firebox. The water might make it to the ground, but the leak originates in the firebox. Which means nasties get out. Plus one leak is usually just the start of more.

I would forget about it & just get a furnace designed for the job. Your insurance will be no good, for one simple starter thing.

 

[E Yoder]

On the outdoor boilers I've worked on leaks are inside the firebox from condensation (as maple1 mentioned) or rain water (over summer) on mild steel units or rotting through to the outside of the water jacket due to sludge buildup in the bottom of the tank from lack of water treatment.
But I agree, one leak means more coming usually.
I've worked on boilers over 10 years and I'm not sure I would trust myself to know how to design a hot air furnace. So many variables and intricate details that have to be right.
But I never want to discourage a tinkerer!