outdoor wood furnance

Just the furnace (boiler) alone costs about $5K. Another $1K to get
it ready to heat the house, shop and domestic hot water. There must
be a metal worker hanging around here who has built one of these for
thier own use, or at least could if they wanted. If so, please share
the wisdom. Seems to me these things are way over priced. Am I wrong
about that? Certainly someone here knows how to build one better and
cheaper. We got the tools don't we? Hell, everyone here is a
professional weldor! Let's see, you need a firebox, water jacket,
blower, fittings, circulator.... Thanks for any feedback. Dan
Reply to
Dan
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Metal containers that hold water under pressure, and are heated, have a nasty tendency to explode, if not built, installed, and operated correctly. Even if you do manage to build something "safe" enough to operate, you have no guarantee that it won't corrode out in a couple of years.
I'm not saying it can't be done, just saying there are some rather signifigant safety and practical issues to consider before building a boiler large enough to be useful.
Reply to
Wayne Bengtsson
It wouldn't be too much of a problem constructing a non pressurized outdoor wood stove. The controls are quite simple. The problem is getting your insurance company to cover it. For $5000.00 you should be getting a stainless steel stove with an ash auger and a warranty. Here is where I bought my stove 10 years ago.
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Reply to
Sven
I have a couple of friends who many years ago decided to build a wood-fired hot tub. They over-engineered it at every turn. When they got to the first test fire, they filled the tub and stoked a good fire in the box and sat down to watch the Super Bowl. At halftime they went out to see if the tub was warm yet. It was *boiling*! That tub got torn out and a sauna built in its place. The sauna had electrical heating controls ..
Grant Erwin
Sven wrote:
Reply to
Grant Erwin
I've built an indoor boiler by getting two short pieces of very large oil line or gas line pipe. In my case, I got a 3' section of 30" and a 3' section of 36". The back is just a flat sheet, the front a flat sheet with a door installed. The water jacket is the area between the large pipe and small pipe, the fire box the inside of the small pipe. Easy to build - about one day of welding after a month of looking for the right parts.
For an outside unit, I'd go with the Hausha idea. Build a standard fire box. Put it in a small concrete block doghouse. Insulate the heck out of the building. Put a roll of flex copper tubing around the firebox very loosly. Fill the gap between the wall and the firebox with sand. The fire heats the sand and block and is a huge heat sink to help carry when the fire dies at 3:00 AM. Water circulating though the copper pipe will pick up the heat. Very simple to build. I've seen HUGE ones that you load with a bobcat. Put in pallets, sections of trees, tires (after dark), one even took corn stalk round hay bales.
Karl
Reply to
Karl Townsend
My Dad put one of these in, its not pressurized, just circulating hot water. Works like an airtight stove so you get a long controlled burn. Its installed in an out building linked to an exchanger in the house (also with an electric furnace) through underground plumbing. Isn't corrosion largely a matter of what liquid you have in it? It couldn't be that hard to google your way to a life expectancy info for these units
Reply to
Michael

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