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Started by SPD748, January 10, 2017, 07:13:35 PM

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SPD748

Hello all,

I have a bit of a new project on the board and I'd like some opinions. I recently moved to a home that doesn't have a fireplace. I'm really missing my wood heat, I mean REALLY missing it. I've ran through all the possibilities which have all lead to an OWB. A manufactured unit looks to be in the $7-$8000 range. I believe that I can build one for much less. Now, it won't have the newest, latest, greatest features that commercially manufactured units have however I think I can design something that will be fairly efficient and last many years. Basically a ~15 cu ft firebox surrounded by ~175 gallons of water, aquastat, forced air, solenoid controlled damper, water pump... Unless I've missed something, I think it could be constructed for around $2000.

That being said, are there any opinions here? Someone that build one with advise on how to avoid pitfalls? Someone that attempted and discovered that it wasn't financially doable? General thoughts on the matter?

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

Gearbox

There was a company in Wisconsin that was using 500 gal propane tank cut in half for the firebox . If you look around in salvage yards you can find them with the valves pulled . You may even find one big enough for the water jacket .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

thecfarm

I have the older style Heatmor. Just about what you want to build,but no solenoid controlled damper. I myself would forgo that part. That is why I bought a Heatmor,a very simple design. Most parts are just common boiler components,nothing fancy,Honeywell controllers. Two blowers to drive oxygen in the firebox and a bladder. I also have water flowing through the door too.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

SPD748

Thanks Gear!

I already have a 26" diameter cylinder that's 48" long, rolled from 1/4" steel. I could go with a 44" diameter water jacket which, with the 26" firebox inside, would leave ~47,500 cu in of volume or ~200 gallons without loses such as the chimney, bracing, etc.

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

JSNH

Search on the web many people have made their own.
Seeing your work on the mill. I know you can look at many boilers and pull the best ideas together for yourself. Your ability is top shelf and you take the time to do it right. You will make an outstanding stove. Document your build here and inspire others as you have done before.

SPD748

JSHN,

Believe me, I've been pouring over page after page of web documentation. I will share this build here and, as before, I hope it will inspire someone out there to do the same.

One question has come up... Is there scientific relation between the size of the firebox (i.e. surface area of the heat transfer plate) to the volume of water the tank will contain. In other words, is there a magic number or range of gallons of water to available fuel volume? Is 100 gallons half as good as 200 gallons? Is more (or less) better? I understand that more water will take more energy to bring up to temperature however said volume of water will hold said energy longer. Based on this, and nothing else, the largest possible volume of water would be best however there's always the law of diminishing returns.

I could just mimic a commercially fabricated unit however I'd really like to understand the science behind this project in lieu of going with a WAG. Know what I mean?  :)

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

dave_dj1

I believe it all boils down to how often you want to feed it and the load you put on it. A Garn can be fired once a week in the right setup.
There is a (what i feel is) a good design with the tank in tank with the chimney down 3/4 of the way into the firebox.
That is the style I am going to copy if I ever get around to it. I believe in natural draft, at least once up to temp. I feel the blower burns more wood than it should. Just my .02 worth. Good luck. ;D

thecfarm

Yes the blower might blow too much,but when the blowers are not on the Heatmor that I have,the fire is smothered out. Open up the door and you would think the fire is out. This allows me to burn cedar and dead wood that with a natural draft I could not control the fire.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

snowstorm

my taylor holds 900 gal of water. take a look at how the smoke tubes are in a taylor going down and back then up and towards the front

Gearbox

I would go with some kind of shaker grates . My Crown Royal with dry oak has only clinkers what will pass the holes in the grate . Why put wood in to make charcoal . Induced draft with variable speed . Upper secondary burn .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

DDW_OR

here is a link to my Central Boiler 750 install
https://forestryforum.com/board/index.php/topic,92218.0/all.html#lastPost

the outside temps have been around +18 to +38. one load of madrone wood, 22 inch long, in the CB-750 has lasted FOUR days. the inside temp is +72

the next load of madrone lasted SIX DAYS at similar temps.

"let the machines do the work"

SPD748

Thanks so much for the information and opinions guys! Here's what I have for design so far...

A 26" diameter x 48" long firebox rolled from 1/4" plate. I'm thinking about welding in a flat plate on the bottom so a shovel will scoop out the ash easier. I looked at the grate and shaker grate systems. While there is no doubt this style of ash removal may be convenient, I think a simple flat bottom will work fine. Push the burning material toward the rear with a rake, shovel out the powder, pull the burning material back toward the front then add more wood. I think it would be easier to repair a flat bottom vs a grate/ash drawer style as well. I'm still open to hear that I should go a different route there however so keep the opinions coming!

A 42" square x 60" long tank formed with 3/16" plate. That would allow for a ~300 gallon water capacity. Normal plumbing arrangement. I like the idea of having the chimney extend well into the firebox to trap heat at the top of the chamber. A forced air blower in a well insulated door, which will be 24" square. Wrap the sides and back of the tank with several layers of fiberglass insulation.

This unit will sit inside a building so there won't be a need to finish the exterior with sheet metal, like commercial available units. I may do something to neaten it up but I don't think I'll spend a lot of time and effort there. I've sized the building to hold around 10 cords of wood in addition to the furnace.  I like the building idea to help cut the wind off the unit and to have dry wood storage.

I do have a question about the heat exchanger. My air handler is a condenser on top/down draft style arrangement. The fan draws air down through the condenser then through the floor and into the duct. Could I place the heat exchanger between the condenser and the air handler thus the fan would draw air down through the condenser then through the heat exchanger then into the duct? All the pictures I can find have the heat exchanger on the pressure side of the fan. I can't seem to find an arrangement where the heat exchanger is on the suction side of the fan, exactly like mine.

Thanks guys!

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

hedgerow

Lee
Just a couple things to think about. I too was going to build a wood boiler of sorts year ago. I also wanted it in a building because I don't want to be out feeding wood outside when it is -20 and the wind is blowing. My insurance company wouldn't cover my building any more with a none UL listed wood burning device in it. That forced me into to buying a Garn that is listed and designed to be installed in a building. I have three furnaces in my house that my heat exchangers set above the AC coil but all three are on the supply side as my are up flow. Shouldn't matter that yours is a down flow you AC coil works Ok?

thecfarm

The heatmor that I have they run 4X8 rectangle tubing the length of the top. The smoke goes up into this tubing in the front of the OWB travels the length of the OWB and exit in the back. Make your chimmney out of ¼ inch pipe.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

Ljohnsaw

Quote from: SPD748 on January 15, 2017, 10:22:45 AM
I do have a question about the heat exchanger. My air handler is a condenser on top/down draft style arrangement. The fan draws air down through the condenser then through the floor and into the duct. Could I place the heat exchanger between the condenser and the air handler thus the fan would draw air down through the condenser then through the heat exchanger then into the duct? All the pictures I can find have the heat exchanger on the pressure side of the fan. I can't seem to find an arrangement where the heat exchanger is on the suction side of the fan, exactly like mine.

Thanks guys!

-lee

Absolutely NO experience here, but, putting the blower on the "hot" side would mean your lubrication for your bearing is being cooked.  How hot is the exchanger running? 120°? 180°?  That would be my only concern.  Well, that and if it springs a leak - is the exchanger physically above the fan?
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

Gearbox

I would weld in 2 or 3 or4 angled cross tubes across the top . The reason to angle is to reduce the chance of boil in the tubes. Mine are flat and at 190 it will start chunking[boiling ] in the cross tubes .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

JB Husky

SPD... A couple of questions for you. Are you building this because you can't afford to buy one? (Not trying to get in your business) I built one about 6 years ago because I couldn't buy one and I'm now looking to buy one. These stoves are inherently inefficient even when engineered and tested by manufacturers who spend big money on R&D. Not doubting your ability just pointing out the obvious. Secondly the heat exchanger can be configured they way you describe, my old furnace was, but is there any way to get it downstream of the fan? It cost me a fan motor by having the heat exchanger upstream of the fan. As for the construction of the stove the dimensions you have listed are close to mine, as my firebox is 30" in diameter and 36" long made of 1/4" steel. The water jacket is a 42" diameter 48" long 1/2" wall pipe. If I were going to do it again I would do as you said and extend my flue down low in the firebox or create some sort of baffle. I used a damper instead and I lose a lot of heat out the flue. Another thing I would change would be sloping the walls of the firebox towards the middle so as the fire burns down your wood in theory will all fall together. I'm sure if I think more about it I can think of some other stuff I would change. Best of luck to you.
455 Rancher
562 xP
Stihl 460
Echo 750 EVL
Antique Brave splitter

SPD748

hedgerow,

I haven't thought about the insurance angle. I'll ask them and see. The boiler will be in a dedicated building so the loss would be contained to the structure, wood pile and soft parts on the exterior of the unit. I really haven't thought about the insurance. Thanks for bringing that up.

cfarm,

Based on your suggestion, I'm thinking about a horizontal plate open in the rear of the firebox and making a 90° turn at the front then exiting the top. With a fan in the front forcing air from front to rear, I think it would be wise to have the smoke/heat travel from back to front to collect as much energy from the exhaust as possible. Smoke generated near the door would have to travel the length of the firebox twice in order to exit. 1/4" pipe is an excellent suggestion.

ljohnsaw,

Believe me, I've really been stressing about the heat exchanger arrangement. A solution will be to build a plenum to sit under the air handler. This would eliminate all possible heat related issues and, in the event of a leak, would save the electrical components though the floor might not like it >:(.  My lineset is long enough to allow the air handler to be raised 24 inches or so. That should be plenty.

Gearbox,

Do the tubes you're referring to carry water? If so, are they pressurized or to they just connect one side of the tank to the other through the firebox?

JB Husky,

Though I could shell out the cash for a commercially available unit, I believe (as my Dad taught me) that my hands were made to make things. That being said, I totally agree with you on the point that companies spend tons of money on the research and development of any product in order to make said product as marketable as possible. Now, that marketability may be in the form of efficiency. It could be in the form of lower maintenance. Ease of use perhaps. Some integrated combination of all, and more, of the above. In my experience, efficiency and marketability don't necessarily go hand and hand. Take my sawmill for example... I could have bought a brand new bandsaw. Said bandsaw would most certainly fit the style/type/frequency of sawing that I do much better but then, where is the journey?  :) The time I was able to spend with my Dad working on that Frick is beyond priceless to me. In the end the equation is simple for me. I'm building vs buying for three reasons: 1. It's what my Dad would have done. 2. It's what my Dad taught me to do. 3. My daughter will be partaking in the project. In fact, she will be welding some of the less than water tight areas of the boiler (she just doesn't know it yet  :D). Please don't take my response as rude or assertive. You are correct. A commercially available unit most likely would be more efficient. On to the heat exchanger. I think a plenum under the air handler will eliminate any issues there. I like the sloping firebox walls idea. I'll modify my drawing and post it here. Stay tuned!

This sort of exchange is exactly what I was hoping for! Great ideas and information that, I'm sure, will lead to an excellent result. You guys are the best!

-lee

Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

SPD748

The first of what I'm sure will be many drawings/revisions...



 

cfarm, were you talking about something like this?

-lee

Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

Ljohnsaw

SPD748,

And don't forget, on a commercial unit, one of the most important aspects is price.  While the price of OWB is staggering (to me), you better believe that sound engineering will loose out to economics every time. :-\

I had a wood stove that had what appeared to be an air tube high up in the firebox.  It was 1¼" or maybe 1½" diameter with a series of small holes.  You could see how it was providing fresh air to the smoke.  There was a clear area right by the holes followed by a nice flame.  It was allowing the smoke to combust.  I understand you have a fine line between long burn time vs. efficient burn but I would consider this afterburner an essential part of your design (to keep you from smoking out your neighbors!).  Perhaps having this air supply fixed and a damper on the remaining air input thermostatically controlled?
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

SPD748

Quote from: ljohnsaw on January 16, 2017, 09:24:55 AM
SPD748,

And don't forget, on a commercial unit, one of the most important aspects is price.  While the price of OWB is staggering (to me), you better believe that sound engineering will loose out to economics every time. :-\


Agree 100%. As a toolmaker, I watched our engineers toss great ideas because upper management decided it wasn't "cost effective" id est a simple change in design would make servicing the product many times easier however, "We're not in the business of making things easier for the customer later. We're in the business of making money now. Got it?" When I designed my log splitter, I considered repair and replace aspects long before I cut the first piece of metal. That design changed many times as it progressed. My Dad often proclaimed, "The way things are built these days, a mechanic needs three arms and six elbows to work on the thing."



Quote from: ljohnsaw on January 16, 2017, 09:24:55 AM
I had a wood stove that had what appeared to be an air tube high up in the firebox.  It was 1¼" or maybe 1½" diameter with a series of small holes.  You could see how it was providing fresh air to the smoke.  There was a clear area right by the holes followed by a nice flame.  It was allowing the smoke to combust.  I understand you have a fine line between long burn time vs. efficient burn but I would consider this afterburner an essential part of your design (to keep you from smoking out your neighbors!).  Perhaps having this air supply fixed and a damper on the remaining air input thermostatically controlled?

I'll research the afterburner concept. I can't seem to get a grasp on what you're describing at the moment. Perhaps more coffee is in order...

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

Ljohnsaw

Quote from: SPD748 on January 16, 2017, 09:38:42 AM

I'll research the afterburner concept. I can't seem to get a grasp on what you're describing at the moment. Perhaps more coffee is in order...

-lee

That's ok.  It happens quite often to me ;)  IF the smoke/gasses are hot enough, all they need is air and they will combust.  Injecting air to the (hot) smoke and it will burn.  That will give you heat and lessen creosote buildup.  I somewhat understand that OWBs are trying to maintain a certain water temperature so my concept my not apply - it might be too efficient and over heat the system.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

gspren

  My background is also tool & die and later experimental fabrication. On my older, conventional Portage & Main OWB the smoke enters what I call a smoke shelf in the rear comes to the front and makes a 180 to exit the rear. This is a rectangular tube about 20" wide by 6" tall with a baffle stopping about 10" from the front, so each passage is 6" x 10". Above the main loading door is a separate door to clean the shelf of all the little ashes that settle there, this is surrounded by water. Two huge benefits are that with all that area to cool the smoke I never see sparks coming out the stack and in the roughly 10 X 20 x 6 tall area just inside the front smoke shelf door the temp rarely exceeds 350 degrees so you can do roasts and baked taters. Since all threads mention food I wanted to take care of that.
Stihl 041, 044 & 261, Kubota 400 RTV, Kubota BX 2670, Ferris Zero turn

snowstorm

a easy way to make a smoke shelf  use a piece of well casing . run it out the back and it will fit a stove pipe

Ivan49

 I have built 3 of them about 13 years ago and all 3 are still in use yet today. Go like the plans you drew and instead of a shelf get a chunck of sq tube and weld it to the top of the firebox on the inside. Cap one end and run the stack up about 3/4 the way back out the top. If you run it out the back you may have problems as I know some friends that went that route and they had to add a cleanout on the back. The sq tube becomes you baffle and you can weld you stack to he top on one end. To  seal your door up use 3/4 inch chanel and make it so it over lap when the door is shut. In the groove on the stove place your rope for a seal. Use silicone spaced about 3 inches apart all the way around to hold the rope in place. DON"T fill this gap up with silicone to hold the rope in place. I did this and I said a lot of nice words getting the old one out. I know of one person that filled the gap up full of silicone and this became his seal. Roll your fire box, my first one has a sq box and it works but the other 2 had the rolled fire box and they work better. I added grates in the first one but I took them out later, they worked but the heat warped them. I used some heavy steel as that is what I had, but if you use cast iron it will work. The door on mine is a 1/2 thick plate and it has a air box over the outside where the fan draws air in the fire box and it keeps the door cool. I used 12 inch thick blanket Insulation on mine but some friend built one and put it in a building. They used steel studs and built a small building around it then they used blown in fiberglass insulation and fill this room full. Theirs will hold a fire for about 20 hrs when the temp outside is  10 degrees. If you don't count thee wire welder I bought I figure I ha about 1000.00 in each unit. My back ground was a machinst for 25 years building die cast machines

thecfarm

That is what I meant. I do have a clean out for any soot that drops down into that 4x8 tubing. I take off the plate and shove a piece of flat stock,I think 3X7 with a long piece of rod and push it out by the feed door. I do this 2 times a year or when I think of it.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

SPD748

Thanks guys!

To clarify, should the smoke enter the shelf/tube in the rear of the firebox then exit toward the front? Enter in the front (door end) and exit toward the rear? Another arrangement perhaps?

I ask because, in my mind, it makes more sense for the smoke/gasses to enter the shelf/tube toward the rear of the firebox. If I load on the door end that would force the gasses to travel the longest path to enter the shelf/tube thus giving more time to transfer heat to the firebox shell. That's my theory at least. Most of the simpler designs I found had a straight chimney pipe extending into the firebox what looked to be about half the height of the firebox itself. I suppose this is intended to trap heat above the vent opening. That was my thought as well until you guys suggested a shelf or tube. Honestly, I like the shelf/tube idea better. I just need to settle on exactly where to put the chimney exit and move on to the next step.

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

thecfarm

Not saying Heatmor does it right. The smoke travels the lenght of the firebox towards the feed door,goes up into an opening about 8 inches of some shape? travels the length of the firebox again through a rectangle opening about 4X8 inchs and than goes up into the smoke stack,whch is at the back of the OWB.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

thecfarm

Not that this picture will really help.



 

Right above the warning sign is a plate that I remove to shove that 3X7 cleaning rod through to clean out that recantangle tube. Those are shiny nuts you see on each end,maybe 3/4 in size.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

gspren

  On my P&M mentioned above the smoke enters and exits the rear. The shelf is not in the fire chamber but is above it surrounded by water. Since the long horizontal area is bigger at 6x10 than the stack at 6" dia the smoke and sparks travel through slower where the sparks burn out inside. I have never seen a spark coming out the stack.
Stihl 041, 044 & 261, Kubota 400 RTV, Kubota BX 2670, Ferris Zero turn

Gearbox

On mine the smoke travels over the shilf in front and out a rear stack . top blower gives air on top of shelf . Sliding plate opens shelf to let smoke out when filling .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

Bert

QuoteOn mine the smoke travels over the shilf in front and out a rear stack . top blower gives air on top of shelf . Sliding plate opens shelf to let smoke out when filling .

How do you slide the shelf? Mine (Hoss 300) is the same way but theres no way to actually slide that shelf when its so hot. Nothing to grab with a steel poker either. Guess i need to tack weld a handle on there i can grab with my fire poker.
Saw you tomorrow!

Gearbox

There is a rod that comes out the front attached to a plate on rails that opens a hole under the stack .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

gspren

  Looks like you need to do a 2 week tour of the NE looking at/in OWBs.
Stihl 041, 044 & 261, Kubota 400 RTV, Kubota BX 2670, Ferris Zero turn

SPD748

Quote from: gspren on January 17, 2017, 02:34:16 PM
  Looks like you need to do a 2 week tour of the NE looking at/in OWBs.

Man, do I ever  :)

I've decided to make this a journey for anyone who wants to come along. I plan on taking a little of what everyone suggests and put it all together. I think the destination will be more than satisfying. Like I said, this most likely won't be the nicest, most efficient owb that has ever been however there will be a little piece of many friends in it that will, in my opinion, be priceless.

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

Bert

I envy what you are doing and wish I had the skills to pull it off. A water tight weld is not something i'd feel comfortable with when dealing with my families heat source. Thats just a reflection of my own personal skills and in no way a knock on what your out to accomplish. They really are just a firebox surrounded by water in the simplest terms and really the commercial prices are way high for what it truly is. Ive had both a mahoning and now a Hoss and any insight I can give is all yours. The Hoss (tennessee outdoor boilers) is hands down a better unit in design. One door to deal with is nice.
Saw you tomorrow!

Ljohnsaw

I've got some questions that probably any OWB owner can answer:

1) Do you line the firebox with bricks (maybe just the bottom) to help the steel last longer?  Or is the firebox directly in contact with the water and you don't want any "insulation"?

2) Is the firebox and/or outer jacket ever made of stainless steel so it "never" rusts out?

3) Do you have a float valve or a large tank level with the OWB to provide makeup water? (not sure where any would go) Or do you just have a very large amount of water in the system and check every now and then?

4) How much water do you have in a system?
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

DDW_OR

Central Boiler Edge 750
1=no bricks
2=steal. water had rust inhibitor added. must use test kit to check PH and nitrite
3=no float valve. valve with a clear plastic tube on back. open valve to see level of water. then close valve to drain water out of plastic tube.
4= about 300 gallons
"let the machines do the work"

SPD748

My latest revision:



 

The gasses enter the 6" sqr tube inside the firebox, travel toward the door then make a 90° turn and travel into the upper 6" sqr tube. A second 90° turn and they travel toward the rear of the unit. The upper 6" sqr tube is in the water jacket. A final 90° turn and the gasses travel up and out the chimney.  The upper tube extends out the rear of the water tank and is capped with a removable door. The lower tube has a removable door attached to the front (firebox door end). These doors would allow the tubes to be brushed out from time to time. Is this arrangement what several are referring to?

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

Gearbox

 I am thinking you need to add a sliding damper on the bottom of the top 6 in square to let the smoke out when you fill . Also you are going to need to induce air into that 6 in tube to get a burn . I would move the clean out to the outside so I could clean it out hot . I am going to try to explain my draft system . 2 blower motors 1 main draft larger than top one . The motors on the blowers hang down so you have a flat blower housing surface for a solenoid operated disk to seal on when it shuts down . Every thing needs to be completely sealed to keep intake air out or it will over run . Some boilers run a very short differential 5 degrees I run 20 degrees on mine and on a warm day I might see 7 or 8 degrees over run .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

Kellyj

A wet base/bottom boiler....nice

The bigger the storage, is more stored BTUs.
Another way to do it is, smaller boiler, with what is called a buffer tank. Most of the more efficient OWB and IWB companies are utilizing buffer tanks.

The key to any wood source boiler is to keep the stack temp low enough that you have drawn out all of the heat, but not so low that you are condensing and building creosote inside of your boiler.



Love to see some pictures
Many projects started, few finished.

Kellyj

Quote"I do have a question about the heat exchanger. My air handler is a condenser on top/down draft style arrangement. The fan draws air down through the condenser then through the floor and into the duct. Could I place the heat exchanger between the condenser and the air handler thus the fan would draw air down through the condenser then through the heat exchanger then into the duct? All the pictures I can find have the heat exchanger on the pressure side of the fan. I can't seem to find an arrangement where the heat exchanger is on the suction side of the fan, exactly like mine."

The Heat coil goes after the "A" or AC coil, in the airflow. Typically both are after the blower, but can be before. Bearings? is it a direct drive? bearings woudln't be an issue. there are several companies that make coils that will fit into your supply duct after the blower.  Unless its like a mobile home, where the duct is slightly impossible to access.


Many projects started, few finished.

Kellyj

Quote1) Do you line the firebox with bricks (maybe just the bottom) to help the steel last longer?  Or is the firebox directly in contact with the water and you don't want any "insulation"?

Usually just on a dry bottom boiler, the bricks protect the steel or other material that is holding up the actual boiler. On a wet bottom boiler, the water is keeping the steel cool enough to not warp. Careful on leaving ash in the boiler too long, or over the summer if not in use, ash and moisture are corrosive.
Many projects started, few finished.

SPD748

Let me get caught up...

Quote from: Gearbox on January 18, 2017, 09:12:28 AM
I am thinking you need to add a sliding damper on the bottom of the top 6 in square to let the smoke out when you fill . Also you are going to need to induce air into that 6 in tube to get a burn . I would move the clean out to the outside so I could clean it out hot . I am going to try to explain my draft system . 2 blower motors 1 main draft larger than top one . The motors on the blowers hang down so you have a flat blower housing surface for a solenoid operated disk to seal on when it shuts down . Every thing needs to be completely sealed to keep intake air out or it will over run . Some boilers run a very short differential 5 degrees I run 20 degrees on mine and on a warm day I might see 7 or 8 degrees over run .

On the damper, would I have it partially closed during normal operation then fully open just prior to opening the firebox door?

I researched the afterburner concept. What I found looked like black pipe with a series of small holes drilled in it. This pipe was placed high in the fire box. It looks like air is drawn into the tube to allow the gases to burn. If I had something like this, would it too need to be automatically closed off somehow during the idle cycle?

The issue with extending the lower 6" sqr tube out the front of the firebox is that it would cut into the available space for a door. I'd really like to go with a 24" sqr door if I can. As you can see in the drawing, there isn't room to run the lower tube through the face of the firebox and have a 24" door. Now, I could go with a smaller door I suppose. The question becomes; would the benefit of having a "hot clean out" arrangement outweigh the benefit of a larger door?

I was going with the forced draft system. Fan in the door with a flap that closes during the idle cycle. I think that's what you are referring to.

I was going with what I found to be the 'standard' 15-20° temperature differential. Something like 160° on and 180° off, adjustable of course.

This brings up another question. Is the water from the OWB continually pumped through the system and into the house or only when the thermostat calls for heat. In other words, does the house thermostat trigger the air handler fan and OWB water pump or just the air handler fan?



Quote from: Kellyj on January 18, 2017, 11:12:22 AM
The Heat coil goes after the "A" or AC coil, in the airflow. Typically both are after the blower, but can be before. Bearings? is it a direct drive? bearings wouldn't be an issue. there are several companies that make coils that will fit into your supply duct after the blower.  Unless its like a mobile home, where the duct is slightly impossible to access.

My air handler fan is direct drive. There is more than enough room to raise the AC coil and place the heat exchanger underneath it. This would be the easiest/simplest installation. If that arrangement isn't desirable, I will have to build a plenum to sit on the floor, underneath the air handler. My AC coil is a little rusty so I was thinking that now would be a good time to replace it. My water heater sits 3 feet to the right of the air handler so the plumbing shouldn't be all that complicated.

-lee
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"Some police officers give tickets, some gave all."

Kellyj

QuoteThis brings up another question. Is the water from the OWB continually pumped through the system and into the house or only when the thermostat calls for heat. In other words, does the house thermostat trigger the air handler fan and OWB water pump or just the air handler fan?

All of the outdoor boilers I set up, the boiler circulator runs all of the time the boiler is in operating mode, off when not in use.
Many projects started, few finished.

SPD748

Quote from: Kellyj on January 18, 2017, 06:05:28 PM
All of the outdoor boilers I set up, the boiler circulator runs all of the time the boiler is in operating mode, off when not in use.

Got it, thanks. It looks like the largest OWB pump I can find would cost around $20/month to operate 24/7. That seems remarkably cheaper than the furnace I have now.

-lee
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410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
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Kellyj

Got it, thanks. It looks like the largest OWB pump I can find
Quote

Largest you can find??

Your "circulator" should be based on GPM and feet of head requirements. Why put something on that might be twice the size you need, or worse, undersized?

A typical OWB circulator is like a Taco 0014, but I've installed bigger circulators if needs require.

No, I don't do OWB's everyday.
Many projects started, few finished.

Gearbox

If you have no lift you can use a Taco 007 If you need to lift water much above the boiler go with a Taco 011 . You will not need a damper in the stack if you can get the draft system shut down tight  . Mine has almost no smoke at idle . With a damper in the stack creosote and sticking may be a problem . Keep the questions coming Better to pick brains now befor the welding starts .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

Kellyj

QuoteIf you have no lift you can use a Taco 007 If you need to lift water much above the boiler go with a Taco 011

Sadly, that is not how to correctly size a circulator.

The height has nothing to do with calculation.

Many projects started, few finished.

SPD748

Quote from: Kellyj on January 18, 2017, 06:30:02 PM
QuoteIf you have no lift you can use a Taco 007 If you need to lift water much above the boiler go with a Taco 011

Sadly, that is not how to correctly size a circulator.

The height has nothing to do with calculation.

I was under the impression that it takes more pump to vertically move water than it does to horizontally move it. Isn't 'feet of head' synonymous with 'height'? I could be wrong though.

I mentioned the "largest" pump as a comparison to my current electrical heating requirements. Believe me, there will be great thought put into sizing the proper pump for my application.

On that note, I plan on installing the OWB in a location which will require an approximate 90 feet run of pipe, one way. The 'height' difference between the OWB and the heat exchanger/water heater will be approximately 4 feet, with the OWB being lower than the heat exchanger/water heater. These measurements will be collected in a more exact manner once the project reaches that point.

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

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"Some police officers give tickets, some gave all."

Kellyj

I know a plumbers thing.
We need to understand, you're not using a "pump", you're using a circulator.

A pump, like a well pump, builds pressure.
A "circulator", well, circulates water. The only pressure a circulator will build up is outlet side, pushing against the "head", (friction in pipe and fittings) until it reaches the suction side of circulator. It's essentially a closed loop.
Many projects started, few finished.

SPD748

Quote from: Kellyj on January 18, 2017, 06:40:22 PM
I know a plumbers thing.
We need to understand, you're not using a "pump", you're using a circulator.

A pump, like a well pump, builds pressure.
A "circulator", well, circulates water. The only pressure a circulator will build up is outlet side, whpushing against the "head", (friction in pipe and fittings) until it reaches the suction side of circulator. It's essentially a closed loop.

I think I understand. You're saying that, in an open loop, water that needs to be pumped 'uphill' requires a different calculation than water that needs to be pumped 'uphill' then back within a closed loop.

-lee
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"Some police officers give tickets, some gave all."

reride82

Quote from: SPD748 on January 18, 2017, 06:43:57 PM
Quote from: Kellyj on January 18, 2017, 06:40:22 PM
I know a plumbers thing.
We need to understand, you're not using a "pump", you're using a circulator.

A pump, like a well pump, builds pressure.
A "circulator", well, circulates water. The only pressure a circulator will build up is outlet side, whpushing against the "head", (friction in pipe and fittings) until it reaches the suction side of circulator. It's essentially a closed loop.

I think I understand. You're saying that, in an open loop, water that needs to be pumped 'uphill' requires a different calculation than water that needs to be pumped 'uphill' then back within a closed loop.

-lee

You are correct Lee. When you have to pump one way up a hill, you need to overcome the vertical head, and 4' vertical head is minimal. But, in a closed loop such as this, it works more like a syphon and you need to overcome the restrictions within the system I.E. sharp turns, undersized piping, long distances, valves, etc.

Levi
'Do it once, do it right'

'First we shape our buildings, then our buildings shape us'
Living life on the Continental Divide in Montana

Kellyj

First, I'm doing this on my phone, some spelling errors.

You're not pumping, you're circulating.
There is no "uphill" calculation.

Sizing the "head" requirements are based on pipe size, length, fittings, and equipment you are circulating through. Then we need to know your BTU load, 1 gallon @ 3-4 fps will flow 10,000 BTUH.

Lastly, though you can put OWB lower than your heating appliance, you will have less problems if it is equal to or higher. Unless of course, you are making a pressurized boiler.
Many projects started, few finished.

thecfarm

 I had Taco 14 on mine OWB. I had it installed by someone that knows,but they was too big for what I needed. The guy gave it some thought and his thinking was the water was still going fast when it came back around and was making the propeller spin too fast. Dropped down to 007 and my pumps started to last more than a month or 2. He was real nice. Returned my money of 2 Taco 14 and I went and bought 2 007. Was quite a price difference too.
I have about a 25 foot run into the house and it drops down about 4 feet. Into the garage it raises about 7 feet.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

SPD748

Quote from: Kellyj on January 18, 2017, 06:55:38 PM
First, I'm doing this on my phone, some spelling errors.

You're not pumping, you're circulating.
There is no "uphill" calculation.

Sizing the "head" requirements are based on pipe size, length, fittings, and equipment you are circulating through. Then we need to know your BTU load, 1 gallon @ 3-4 fps will flow 10,000 BTUH.

Lastly, though you can put OWB lower than your heating appliance, you will have less problems if it is equal to or higher. Unless of course, you are making a pressurized boiler.

Thanks. I'll keep that in mind when building the OWB frame. I may be able to lift the unit high enough to make it level with the heat exchanger/water heater.



Quote from: Gearbox on January 18, 2017, 06:25:57 PM
Keep the questions coming Better to pick brains now befor the welding starts .

I totally agree. I'd rather make mistakes in the abstract than in fabrication. Abstract is free, fabrication... not so much  ;)

-lee
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Kellyj

QuoteI had Taco 14 on mine OWB. I had it installed by someone that knows,but they was too big for what I needed. The guy gave it some thought and his thinking was the water was still going fast when it came back around and was making the propeller spin too fast.

How can a circulator, in a closed loop make itself spin too fast?

The Taco 0014 is a different animal than a 007, for sure
Many projects started, few finished.

gspren

  Lee, on your last drawing your smoke shelf/tubes are close to what I describe except on my P&M they are side by side both in the water chamber. Smoke enters in left rear and travels forward to a 180 then exits right rear straight out the back into a T, if you take the cap off the T and open the front clean out door you can see straight through. I am not saying that's better, only describing what I have, you seem to know what your doing and I'll bet it works fine when your done.
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thecfarm

Kellyj,I can give you his number and you can ask him. ;D  All I know is I went to the 007 and all the problems went away. I went through 2 pumps. Now the pumps last for years,instead of a month.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

Gearbox

Kellyj I will disagree When you start a system you will need to push the water up to the heat exchanger fill it expel the air back inside the boiler then after that you have a closed loop . Now if you are in - 20 below zero and you have a 007 that will not expel the air back to the boiler and you are bleeding it out and trying to beat the frozen pipes . now do you see why I recommend a pump big enough to expel the air . Yes it is not needed till it is .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

Kellyj

 
QuoteAll I know is I went to the 007 and all the problems went away. I went through 2 pumps. Now the pumps last for years,instead of a month.

I can believe your problems went away, just cant see a circulator that is chasing a circle through a piping system, how it can make itself spin faster ::)
Many projects started, few finished.

Kellyj

QuoteKellyj I will disagree When you start a system you will need to push the water up to the heat exchanger fill it expel the air back inside the boiler then after that you have a closed loop . Now if you are in - 20 below zero and you have a 007 that will not expel the air back to the boiler and you are bleeding it out and trying to beat the frozen pipes . now do you see why I recommend a pump big enough to expel the air . Yes it is not needed till it is .

First, i'm not trying to start a arguement with anybody.

Here is 1 problem, that is not what a "circulator" is designed to do.   Yes, I know many people up here that do the same thing, and have the same complaints and problems.

Why are you not starting it till it is -20, like i said in a previous post, that boiler circulator needs to run 100% of the time that the boiler is heating, not on a call for heat.

QuoteLastly, though you can put OWB lower than your heating appliance, you will have less problems if it is equal to or higher. Unless of course, you are making a pressurized boiler.

I repost my previous post, if you want to eliminate 90% of your problems with OWBs, put them equal to or higher than your heating appliance.

100% of the OWBs that i hooked up that are either equal to or higher than the heating appliance have 0 air issues. I also use a plate exchanger if hooking an open boiler to a pressurized boiler, again 0 air problems.
Many projects started, few finished.

SPD748

No arguments, just great dialog and information. Thanks for the ideas and opinions guys! Keep them coming...

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

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"Some police officers give tickets, some gave all."

Gearbox

Pump goes out Draft solenoid sticks and boils over and anyone that has run one can add many more reasons . There boilers and there outside and you will have shut downs unplanned in in cold weather . Some where I live may happen at - 30 to 40 below zero . Any problem I can save someone problems for an extra $75 its cheap to freezing fingers in the cold .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

Kellyj

QuotePump goes out Draft solenoid sticks and boils over and anyone that has run one can add many more reasons . There boilers and there outside and you will have shut downs unplanned in in cold weather . Some where I live may happen at - 30 to 40 below zero . Any problem I can save someone problems for an extra $75 its cheap to freezing fingers in the cold .

you never mentioned unscheduled breakdowns. that is a different discussion. I'm talking, you fire the boiler up in the fall, the circulator runs until you stop feeding wood to it.

Again, i say, that is why you put OWB equal to or above the heating appliance. Nothing worse than it is -20 your circulator dies, you lose your prime as we'll call it, you change circulator, and now (because a circulator won't push air) you have to fight to get that perfect equation of air out or your lines with a device that isn't designed to pump water only move it.

I'm not criticizing you, But over the last 15 years, i've seen all kinds of [I have typed a profane word that is automatically changed by the forum censored words program I should know better] installs with these OWBs, that work if everything is just perfect, where the non licensed installer said, "paper work says it will work"

Again, not trying to argue, just giving facts as i dealt with them.
Many projects started, few finished.

Gearbox

Kellyj your right  sometimes in houses like mine short of filling the ground up 4 feet my boiler is lower than the shop heat exchanger and having a earth bermed walkout on a slab with a water to water plate in the attic is even with  the boiler . We sort of got off track . Like all build projects there will be trade offs . All we can do is try to help with pitfalls .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

SPD748

Here's what I've learned so far:

- Level is better than the OWB being lower than the heating appliance (prime/air issues)
- It isn't a "pump", it's a "circulator" due to the closed loop arrangement thus the sizing calculations are unique
- No damper is required if the draft control seals tight
- The design needs to extract the maximum amount of heat from the burning gasses without cooling them to the point of creosote formation

That last point is where I think I am in this project. I need to iron out a plan for the firebox vent then move on to the next stage.

-lee

Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

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Kellyj

I guess we've all learned something then.
Many projects started, few finished.

thecfarm

Quote from: SPD748 on January 19, 2017, 06:39:08 AM
- No damper is required if the draft control seals tight
-lee

And that if is very important too.
There is a small well before the flappers of the blowers.The back one is the one that when I throw wood is sometimes a piece of small black wood will get thrown into the opening. Or maybe a bunch of small pieces will cause problems.This has caused the flapper not to close all the way. Don't take much air to make the fire go. As I said,if things are tight,just a little bit of smoke comes out of the stake at idle and when I open the feed door it should look black or looks like the fire is out.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

Holmes

 I believe you plan on the water part of the boiler being an open vessel ? It does need to be open to the atmosphere , if not then it needs safety relief valves.  It can become an explosion hazard.  It does not have to be fully open, but at least a few uncapped 2" pipes may be all right. A runaway fire is very dangerous when heating water.  Like welding on a tire rim with the tire on it, deadly.
   Make your feed and return tappings 11/4" and valve them off at the boiler. It's easier to go in pipe size than up in pipe size.  Put a drain or 2 on the bottom of the boiler . Good luck.  I find this interesting.
Think like a farmer.

SPD748

Holmes,

My boiler will be open to the atmosphere. I plan on having a fill tube welded into the top of the tank. 2 1/2" diameter or so. I'd much rather have a boil over than an explosion. I like your idea of making the pipe connections large. I agree that it's easier to reduce size. I can weld in 1 1/4" bungs. I think the normal arrangement is to pull water from the lower section of the tank and introduce water from the heating appliances into the top section of the tank. I was going to install a 2" drain at the rear of the tank.

-lee
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Kellyj

A 2" drain? Are you building a 150hp boiler?
1" would be plenty, 3/4" is normal.

No explosions if you install a relief valve and some kind of an autofeeder on a closed/pressurized boiler.  It also eliminates alot of air problems and less worries if location is lower than your heating appliance.

Most of the preinsulated tubing is 1" or 1 1/4", so 1 1/4" bungs or thread-o-lets are good decision.
Many projects started, few finished.

SPD748

Quote from: Kellyj on January 20, 2017, 07:04:26 AM
A 2" drain? Are you building a 150hp boiler?
1" would be plenty, 3/4" is normal.

:D  1" it is then.

-lee
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Hilltop366

I have been following along with interest.

Ideas:

It is nice to be able to hook a garden hose up to the drain on an indoor boiler, I suspect it would be nice to be able to on a outdoor one as well so you can drain the water away from your work area when working on the boiler.

Keep all inside pieces wet including baffles or smoke shelves so they won't warp and burnout.

Another baffle option, the baffle on my indoor boiler (1970's HS Tarm MB 55) is at the back and is vertical with a second air inlet at the bottom of the baffle, there is a cleanout at the top near the rear, a quick scrape once in a while and everything falls down to the ash bin. Link to picture, https://woodboilers.com/media/wysiwyg/Downloads/Product_Brochures/MB_Solo_Series_Brochure.pdf



No need to make the boiler bottom flat just make the cleanout shovel rounded to match the profile.



Gearbox

You are right on the pump mounted low . I would take water low on one side and put it back in high on the other side to set up a cross flow . Helps with hot spots .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

trapper

Try to find a way to keep the wood from touching the water walls I find if I put a small piece of wood vertical against the firebox walls of my classic I get a much better burn but I have a natural draft not a blower.
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DDW_OR

Quote from: trapper on January 20, 2017, 11:20:57 PM
Try to find a way to keep the wood from touching the water walls..........

my CB-750 has steel rods hung on the sides

in photo below, Left and Right steel bars, removable plates over heat exchanger in back. small bypass door at top for smoke when re-fueling.


  

in photo below, door latch and blower switch
how it works, opening the door releases the electric switch that turns on a fan.


 
"let the machines do the work"

r.man

Two things that I can add from experience, creosote control can be largely achieved by burning very dry wood and any tubes used for heat exchange need to be easily accessed for cleaning. I have an Empyre with 18 tubes running the length of the firebox. The cleanout access door has two large nuts that seal it and has to be lifted off each time. Not a good idea, should be hinged with a latch. I think that the ideal for a single pass heat exchanger is to have the smoke go out the back of the firebox and travel to the front to exit into the chimney area.  This would allow a second door above the firedoor to access the tubes which could be cleaned from the front. This arrangement also allows for easy piling of wood at the front of the firebox to maximize smoke and flame travel. I home built my first stove 20 years ago with basically no budget and have been itching to try it again with what I have learned since. Another interesting thing that I have only seen on one make of stove is a large duct like smoke diverter above the firedoor. If you look at many furnaces you will see that most have a heavily blackened area there, if you are in a building you might want to consider that. Unfortunately the front cleanout door and the duct are not compatible together.
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SPD748

After hours of reading and thinking and more reading I think I have settled on this design:



 

It definitely won't be super efficient (or even as efficient as most if not all the commercially manufactured units) however I think it will work. As mentioned, there is a clean out door on the front of the unit to handle creosote duties. R.man is on to something with the hinge and latch arrangement. I really like tool-less maintenance features. I've found that I tend to keep up with maintenance duties better if I don't have to hunt a tool first  :)

I think I'll extend the firebox opening so that I might avoid the blackened area just above the door. That should give the smoke room to rise without staining the front of the unit.

-lee
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Gearbox

You still need a way to get air in to the second burn chamber and then close it off .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

gspren

   It should work as drawn but I wouldn't bring the chimney pipe halfway into the fire box, you may get so close to the hot coals that your getting hotter air, 1/5 to 1/4 is as far down as I'd put it. Is the area just inside the cleanout door big enough for a pan with a roast?
Stihl 041, 044 & 261, Kubota 400 RTV, Kubota BX 2670, Ferris Zero turn

Mt406

Hi

I have been thinking of building my own OWB. My design is similar to yours.
I would think it mite set up a creosote problem buy running the flue pipe though the water jacket horizontal.
You would gain heat in water jacket but would you cool exhaust gas to the point of creosote.
Would running it horizontal in the fire box work better.

Just my two cents
Scott

really good info in this topic thanks for the good input everyone I am not ready to start my build yet you are giving me ideas   
 

gspren

Quote from: Mt406 on January 25, 2017, 01:05:38 PM
Hi

I have been thinking of building my own OWB. My design is similar to yours.
I would think it mite set up a creosote problem buy running the flue pipe though the water jacket horizontal.
You would gain heat in water jacket but would you cool exhaust gas to the point of creosote.
Would running it horizontal in the fire box work better.

Just my two cents
Scott

really good info in this topic thanks for the good input everyone I am not ready to start my build yet you are giving me ideas   


   My Portage & Main OWB runs horizontal through the water jacket and creosote has not been a problem, just need to scrape it a few times a season. A plus to that is that the embers burn out before going up the stack.
Stihl 041, 044 & 261, Kubota 400 RTV, Kubota BX 2670, Ferris Zero turn

NWP

Quote from: Gearbox on January 18, 2017, 07:52:35 PM
Kellyj I will disagree When you start a system you will need to push the water up to the heat exchanger fill it expel the air back inside the boiler then after that you have a closed loop . Now if you are in - 20 below zero and you have a 007 that will not expel the air back to the boiler and you are bleeding it out and trying to beat the frozen pipes . now do you see why I recommend a pump big enough to expel the air . Yes it is not needed till it is .

I have a hose bib on the outlet side of the circulator.  When I start the unit up in the fall, I hook a garden hose up from the house and turn the valve off between the circulator and hose bib. This forces the pressurized water throughout the system and back through the return line.  It only takes about 30 seconds and all the air is expelled and is ready to go for the season.
1999 Blockbuster 2222, 1997 Duratech HD10, 2021 Kubota SVL97-2, 2011 Case SV250, 2000 Case 1845C, 2004 Case 621D, John Deere 540A, 2011 Freightliner with Prentice 120C, 2012 Chevrolet, 1997 GMC bucket truck, several trailers, and Stihl saws.

thecfarm

My heatmor is like gsprens. Never had a problem with cresote. And I have burned green wood as an experment. Cut it down,cut it to lenght,split it and burn it. Both softwood and hardwood. Never had a cresote problem. As he stated,just scrape it a couple times a season.
There is no pipe that hangs down on my heatmor. Just a round opening that the smoke goes into. Not trying to say anything,but maybe there is a reason the smoke enters the 4x8 inch tubing by the feed door on a heatmor.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

hedgerow


[/quote]

I have a hose bib on the outlet side of the circulator.  When I start the unit up in the fall, I hook a garden hose up from the house and turn the valve off between the circulator and hose bib. This forces the pressurized water throughout the system and back through the return line.  It only takes about 30 seconds and all the air is expelled and is ready to go for the season.

[/quote]  When I set my system up I bought the circulator mounting fitting that had the valves and the hose bibs on them. That was the best thing I did it is a great place to add liquid or remove air from the system.

SPD748

Quote from: Gearbox on January 25, 2017, 08:40:02 AM
You still need a way to get air in to the second burn chamber and then close it off .

As I understand the secondary burn theory, there needs to be a tube to allow (atmospheric pressure) air to enter the horizontal pipe which, in my design, runs through the water jacket. What I found looked as simple as 3/4 black iron pipe with a series of small (1/8" ish) holes drilled along it's length and a cap on the end. What I can't find is... does this air tube need to have some kind of automatic shutoff (when the unit is in the idle mode) or is it open to the atmosphere full time?



Quote from: gspren on January 25, 2017, 08:45:17 AM
   It should work as drawn but I wouldn't bring the chimney pipe halfway into the fire box, you may get so close to the hot coals that your getting hotter air, 1/5 to 1/4 is as far down as I'd put it. Is the area just inside the cleanout door big enough for a pan with a roast?

I'll move the chimney pipe up in the firebox. The idea was to create a space above the coals that would trap heat before the gasses have a chance to enter the chimney. The pipe (as drawn) is 6" square x 1/4" wall tubing. I would need to fabricate a 6" square to 6" round collar to which the insulated pipe that will comprise the exterior chimney would attach.



Quote from: NWP on January 25, 2017, 05:00:24 PM
I have a hose bib on the outlet side of the circulator.  When I start the unit up in the fall, I hook a garden hose up from the house and turn the valve off between the circulator and hose bib. This forces the pressurized water throughout the system and back through the return line.  It only takes about 30 seconds and all the air is expelled and is ready to go for the season.

That's an excellent idea! Thanks. I'll definitely install a similar fitting arrangement.

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

Bill Saf

Quote from: SPD748 on January 15, 2017, 10:22:45 AM



Wrap the sides and back of the tank with several layers of fiberglass insulation.



I do have a question about the heat exchanger. My air handler is a condenser on top/down draft style arrangement. The fan draws air down through the condenser then through the floor and into the duct. Could I place the heat exchanger between the condenser and the air handler thus the fan would draw air down through the condenser then through the heat exchanger then into the duct? All the pictures I can find have the heat exchanger on the pressure side of the fan. I can't seem to find an arrangement where the heat exchanger is on the suction side of the fan, exactly like mine.

Thanks guys!

-lee

Lee,

I would use foam insulation it has a higher R value then fiberglass.

When I put my OWB in I built a double plentum for the heat exchanger I have a down forced air furnace and had a concern about a water leak with electric coils and put the heat exchanger under the furnace. The plentum is just a double box with a shelf to hold the heat exchanger the furnace sits on top of the box. Are you going to heat your water with a side arm water to water or just heat? if your going to heat your water to you can put a air bleed a the top to vent trapped air. my side arm is the high point on my system. 
Just my .02 worth

Bill

SPD748

I'm back, sorry. My day job got a little busy.

I'm working on my door design. I won't have an ash grate so I'll have to mount the blower on the firebox door. Looking at other designs, it looks like the blower is simply mounted directly to the door. My concern is that the blower will over heat when it's not running as the interior of the door would be exposed to the heat of the fire box and, with the blower shut off, there wouldn't be any air passing blower motor, blade and housing. Any ideas as to how this arrangement works?

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

DDW_OR

here is how mine does the air flow
the furnace door is above this

 
"let the machines do the work"

SPD748

That set up looks like two natural draft inlets with one forced air inlet. Haven't seen one like that until now. Interesting...

The door's I've found that have a fan mounted on them (Taylor has this arrangement) seem to all be insulated with what is most likely Kaowool. Building a similar one won't be much of an issue however I still can't figure out how the heat from the fire doesn't affect the fan, which has to be mounted with a tube or opening of some sort running through the door thus exposing the fan to the heat of the fire when the fan isn't running. I can't seem to find any close up pictures of a door with a fan mounted on it. Ideas?

-lee


Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

SPD748

Sorry for the extended absence. I took a little time off to sort some things out. Have no fear, all is well. I'm reviving this thread first because it's the most "needed" item on my project list. I settled on a boiler design and have most of the materials on hand to move forward. It's the btu requirement and head calculations that are the bottleneck at this point. I tried the online calculator route and quickly observed a wild range of "answers." Here's what I have so far:

My home is heated with an electric furnace which has a single 10kW heating strip. With the thermostat set on 66 degrees the furnace used 2000 kWH in the last 30 days. This useage is usually the highest I'll see per month in a given year. We had a bit of a "cold" snap here (cold for NC that is). I did a little research on the previous 12 power bills and noticed that during the spring/fall months (heat/air conditioner not running all month) the power usage fell by approximately 2000 kWH which leads me to believe the furnace used that amount last month. That being said, I did a little math and concluded that my furnace element produces approximately 35,000 btu and had a run time of approximately 28% last month. IF these calculations are correct, does this mean I could heat my home with ~ 35k btu input from an OWB? Turn the thermostat up a few degrees and have a longer run time perhaps? It seems this way, in my mind at least however I've been very wrong many times in the past so...

My OWB will be placed ~130 feet from the house for a 260 foot total loop. I plan on installing a 30 plate heat exchanger for domestic hot water first in the loop then an 18" x 18" water to air heat exchanger in the air handler to heat the home. I plan on running 1 1/4" insulated lines (1.07" i.d.) from the OWB to the house.

My problem is that I have several numbers/specs and don't know if they're enough to make the calculations or what to do with them for that matter.

Any advise will be carefully considered and much appreciated!  :)

-lee
Frick 0 Handset - A continuing project dedicated to my Dad.

410 Deere, 240 Massey... I really need a rough terrain forklift :)

Sawing Since 1-19-2013 @ 3:30 pm
Serving Since 2002
"Some police officers give tickets, some gave all."

DDW_OR

Quote from: SPD748 on February 24, 2017, 05:58:26 PM
That set up looks like two natural draft inlets with one forced air inlet. Haven't seen one like that until now...........
there is no natural draft

the area in the photo is covered by an 1/8 inch thick steel door
the fan on the right blows air into the center area
then each of the air channels are opened by solenoid. this allows the air that is blown in by the fan to reach the fire.
"let the machines do the work"

Gearbox

I think the domestic water heater needs to go after the heating coil . You don't need that hot [180] to heat your D W . Some where I think I read you only want to pull 2 or 3 degrees out of your water . Mine is doing about 4 degrees at 30 below zero and with the house and shop both calling the boiler runs steady for 2 hours until the shop warms up .
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

Holmes

The 35000btu may heat the house but your real demand is hot water. how many gallons per minute of hot water do you want/ need? lets say you need 3 gpm  3x8.2pounds per gallon is 24.6 pounds of water per minute heated 80 degrees [50 degrees to 130 degrees] is 1968 Btu's per minute x 60 minutes is 118080 BTU's per hour to heat your hot water. I may be wrong with these calaculations but this gives you a general idea . heating is the easy part.
  This will require a 12 gallon per minute flow rate for the circulator
Think like a farmer.

DDW_OR

Quote from: Holmes on January 20, 2018, 09:50:05 PM
......real demand is hot water......
  This will require a 12 gallon per minute flow rate for the circulator

Here is a photo of my double wall hot water heat exchanger
the OWB water enters at the bottom, then exits the top. then goes to the air heater exchanger, then back to the OWB.

all of this is done with the Taco 007 Pump   1/25 hp

Yes I did insulate all of the tubing after I took the photos


 
"let the machines do the work"

DDW_OR

did some research on the Taco
Maximum Flow Rate    1  cubic_feet_per_minute

using my converter "Conversion Tool for Measurements.exe"
feet3/minute = 448.8312 Gallons/Hour
not to bad for a $100 pump that runs 24/7
UPC    687752187311 , 076335100609
"let the machines do the work"

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