Thread: Home made boiler, new at posting here

114_4480.jpg114_4655.jpgFirst time Posting:

I am very new to this posting thing, I built my own wood boiler with secondary air tubes (kinda of like down draft intake) and am looking for critique/ideas/improvements before I bring the boiler on-line later this week.

Run down on construction of boiler firebox, it is square and the top portion has angle iron instead of flat plate, the angle iron is supposed to act as a form of baffles etc. to siphon more heat off the burn, it allowed for more steel surface area also. its 1/4" plate with 1/4" angle for top. Firebox is lined with firebrick and has secondary air tubes. etc.

Water jacket around firebox is 3" and the water jacket outer wall thickness is 1/8" (actually a little thicker, 10 ga).

Logs sit on a grate to allow air to flow under logs.

Intake air is controlled by water temperature, its called "water boiler draft/air controller" at this link : Boiler Room Equipment | Pre-owned Equipment - Division of The Engineer Company I chose this due to its simplicity and electricity is not needed to operate it.

This new boiler system is open system/non pressurized, has an elevated tank for gravity fed expansion, has an 80 gallon hot water heater storage tank that is insulated. Heated water will circulate to heat exchanger inside house, where current pressurized boiler will be hooked to the other side of heat exchanger. Current home propane pressured boiler also heats DHW via Amatrol hotwater maker tank on its own zone. The wood boiler itself is also insulated and it is put in an outdoor shed which has been also insulated, I don't know if it would qualify to call it an OWB?? Got a good deal on CB's thermal pex to the shed which has already been buried.

Please ask any questions and post ideas etc. or teach me how to do proper posting, I will try and attach some pics, I have plenty to show for critique.

thank you for your time and input.114_4479.jpg114_4481.jpg114_4483.jpg

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pics of firebrick shows some missing, i have since finished all firebrick and its actually installed and im waiting till this weekend to get it fired for first time. I have had lots of wood stoves but first time making one.

I'm repping you solely on the work you have done, I dont know jack about the questions you asked.

Originally Posted by GeeVee

I'm repping you solely on the work you have done, I dont know jack about the questions you asked.

Ditto!!

Originally Posted by GeeVee

I'm repping you solely on the work you have done, I dont know jack about the questions you asked.

Thats ok I just wanted some ideas etc. I think I might have to make some slight changes to the air intake tube where the firewood grate rests on (maybe drill some air holes there instead of depending on the upper chamber tubes to supply the needed primary combustion)?? If worse comes to worse I can always remove the upper secondary tubes and just use the tube, its still wood boiler without the upper tubes. was just trying to improve efficiency, I just dont know if primary combustion (fire draft) will draw air down from the upper tubes for a fire.

thanks

I like alot of your ideas you built into your stove. What size is your firebox? I own a factory built OWB and someday when mine gives up I intend to build my own. I think you will need less secondary air and have some primary air under the grate. Do you have a picture of the exhaust exit from in side the firebox? I hope you have some sort of baffle over the exhaust exit. Another idea would be to install a ID fan (or draft inducer) in the exhaust pipe. Any 110 volt blower would work. Just install a pipe about 1 1/2" in the exhaust pipe with a 90 degree nipple pointing away from the boiler. Add a length of pipe and build a flange for your blower to mount to. That would create a good draft. Keep us posted on how it works!

Very nice craftsmanship!

I think you'll find out that you won't really know what tweaks you'll need to make to it until you fire it up for a test run.

Looks GREAT!
I am gonna guess that your little air holes are gonna fill up with creosote but I could be wrong. Like the above post. Once you get it running you'll know.

Just some random thoughts before you set it in place:
Water drain plug.
Additional 3/4" port or 2 in water jacket for future probes sensors or whatnot.

Originally Posted by OH_Varmntr

Very nice craftsmanship!

I think you'll find out that you won't really know what tweaks you'll need to make to it until you fire it up for a test run.

I agree. Very nice!!!!

My neighbor built an OWB 3 winters ago and we are still tweaking it.

My home runs on a system my dad designed. The boiler appears similar to yours, but bigger. The wood box is 3' by 3' by 2.5'. There is water in the walls and in the top of it. A thermostat causes a pump to start circulating the water when it reaches a certain temperature. I have no forced air, merely an air pipe at the bottom which I can manually open and close. The water will circulate through about 300 feet of 1.5 inch copper pipe with rads at every exposed room.

Originally Posted by feader72

Thats ok I just wanted some ideas etc. I think I might have to make some slight changes to the air intake tube where the firewood grate rests on (maybe drill some air holes there instead of depending on the upper chamber tubes to supply the needed primary combustion)?? If worse comes to worse I can always remove the upper secondary tubes and just use the tube, its still wood boiler without the upper tubes. was just trying to improve efficiency, I just dont know if primary combustion (fire draft) will draw air down from the upper tubes for a fire.

thanks

My father and a friend of his designed and fabbed a primary/secondary combustion stove in the 70's, natural induction. Worked fantastic. His stories of burning green popple just make me scratch my head.

Here are the plans to show what I am talking about. I am trying to get my dad to do a revised copy less "chicken-scratchish" but, stare at it long enough and you can figure out whats going on with the primary/secondary and his hand writing.





The next stove my neighbor builds will be a wood boiler version of this.

For the current OWB we have it encased in spray on insulation and the inside of the stove house lined with it.

I hope you might be able to get an idea from that mess of plans regarding primary and secondary combustion.

You do need to mount a drink holder tho on the stove.

Good luck

With the 3 or so units I built I always divert the return flow of water so it circulates the tank and there are no "dead" spots or hot spots. Just a thought. CJ

Just a question, but why only 80 gallons of fluid? I know different size OWBs use various size tanks, but 80 gallons seems small. Of course, I don't have a degree in thermal transfer differential between different materials, I did stay at a Holiday Inn Express last night.

Shea

Originally Posted by vinced

I like alot of your ideas you built into your stove. What size is your firebox? I own a factory built OWB and someday when mine gives up I intend to build my own. I think you will need less secondary air and have some primary air under the grate. Do you have a picture of the exhaust exit from in side the firebox? I hope you have some sort of baffle over the exhaust exit. Another idea would be to install a ID fan (or draft inducer) in the exhaust pipe. Any 110 volt blower would work. Just install a pipe about 1 1/2" in the exhaust pipe with a 90 degree nipple pointing away from the boiler. Add a length of pipe and build a flange for your blower to mount to. That would create a good draft. Keep us posted on how it works!

Thank you for your input, i will attach a side view of the boiler with exhaust (flue). I had originally wanted to put a dampner in the flue (exhaust) pipe but a friend told me because its side exhaust it acts as a dampner already??? I too was thinking that maybe I should drill some holes in pipe near the grate for primary air (or possibly where it has a vertical run to the upper air tubes, this way it would remain clean). I like the idea of the draft inducer, let me see if I understand the principals of it tho', as the air is being blown upwards (out) of exhaust its actually causing more air to be drawn from the intake? how?? I look at it as when the blower is blowing air its getting its air from outside of the boiler, so it really does nothing more than just blow air thru the exhaust pipe? how does this increase actual draft inside the boiler from the intake pipe? If you could clarify i would greatly appreciate it.
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Originally Posted by OH_Varmntr

Very nice craftsmanship!

I think you'll find out that you won't really know what tweaks you'll need to make to it until you fire it up for a test run.

Thank you for your input sir, I think you are probably right. would need a good sized fire to preheat the firebrick and warm up the air tubes too.