# $500 Homemade wood boiler



## strawhousefarm (Feb 27, 2008)

I just posted pictures of the wood boiler that I have been building on our web site. It is built almost completely out of salvaged material. I will have to buy material to close it in or put a skin on it. Right now I have a little over $300 in it as it is in the pictures but I should still be able to finish it for under $500 easily.
The construction was kept as simple as possible, since it was my first one. I didn't want to involve a lot of time and money into it until I knew it would work. I might build an improved model in the future but this one should work for a quite a while.
As it is pictured now it doesn't heat the domestic water that would come out of our faucet but I do plan to add a copper coil inside the water jacket in the future, again I didn't want to do it at first until I was sure it was capable of heating both the domestic and the heating water.
The pictures can be found in the photo album on our web site at
www.freewebs.com/strawhousefarm


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## foxtrapper (Dec 23, 2003)

You put some care and thought into that unit! 

Well done. Wish the folks around here that make their own did so well.


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## js2743 (Dec 4, 2006)

great idea, but i got couple questions do you have a way to release the pressure in the water tank? looks like regular heating oil tank i don't think it could stand any pressure. and did you just use pure water would that cause corrosion and rust out your tank? i'm thinking they use a mixture of water and glycol or something to prevent that. and you have it near your house which is made of straw and the smoke stack is close by one little spark into that straw and your homeless.


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## PyroDon (Jul 30, 2006)

Ok a question 
what are you using as the burn chamber ? 

I aquired a 500 gallon propane tank in hopes of using it as the water jacket and my FIL has gotten me a section of well casing for the burn chamber.


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## MELOC (Sep 26, 2005)

have you seen one of the heat exchangers that are made of two copper pipes, one inside another? that is a feature of many commercial outdoor boilers that heats domestic water. you run the main supply line for the house through the heat exhanger and it continues on to the rest of the house. the exchanger is mounted to the hot water heater using the drain for the return to the smaller pipe and the top of the inner pipe feeds in at the top of the hot water heater. the water thermosyphons through the water heater, heated by the passing water in the main supply line from the boiler as it makes it's way to the house.


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## strawhousefarm (Feb 27, 2008)

js2743 said:


> great idea, but i got couple questions do you have a way to release the pressure in the water tank? looks like regular heating oil tank i don't think it could stand any pressure. and did you just use pure water would that cause corrosion and rust out your tank? i'm thinking they use a mixture of water and glycol or something to prevent that. and you have it near your house which is made of straw and the smoke stack is close by one little spark into that straw and your homeless.


It is a non pressurized boiler. Much safer. I would never even consider a pressurized one. I left one of the two inch inlets in the top of the tank open and I will pipe it outside the siding so in the event that is might reach boiling the pressure and steam will be vented.

The mixture that your talking about is a water glycol mixture along with some anti corosion agents. I went a lot simpler. The inlet on the front plate beside the thermometer is an anode rod. The same thing that helps protect your hot water heater tank at home. Even if it does rust out in a couple years I can either weld a patch over it or just call it a loss and I got a couple of years of next to free heat for $500. Not a bad trade.

As far as the placement of the unit, I was a little worried at first but it burns at a much lower temperature than a woodstove in the house. It just needs to smolder to keep the water temperature at around 120 to 140 degrees.
On top of all that the flue that I used out of the water heater is fluted through more than two thirds of the way so it provides some major spark arrestion.

Hope that explains some of that and thankyou for the concern.


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## MELOC (Sep 26, 2005)

have you looked into the heat exchanger idea i mentioned? i really like it and may use it if i eventually get an outdoor boiler.


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## strawhousefarm (Feb 27, 2008)

PyroDon said:


> Ok a question
> what are you using as the burn chamber ?
> 
> I aquired a 500 gallon propane tank in hopes of using it as the water jacket and my FIL has gotten me a section of well casing for the burn chamber.


It is the water tank out of a 80 gallon gas water heater that had rusted a hole in the bottom. About anybody can go to a plumbing supply house ( not like Lowes or Home Depot) and purchase an old water heater. They usually dispose of old water heaters for plumbers that are replacing them. They usually only get scrap price so they are usually willing to let them go real cheap.


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## strawhousefarm (Feb 27, 2008)

MELOC said:


> have you looked into the heat exchanger idea i mentioned? i really like it and may use it if i eventually get an outdoor boiler.


I'm already familiar with the heat exchanger that you are talking about and I do think it would be a good idea. I think I could make one if I set my mind to it. Also Zurn a company that makes plumbing parts has a reasonable block style heat exchange that I have considered using on the future solar water heater that I plan on building to use to heat the domestic water in the summer.

Thanks for the tip.


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