Anyone have any experience with the DEB designed DIY OWB plans?

[rotaxman]

This has been very enlightening to say the least, while I don't want to reinvent the wheel sometimes its good to go back a revisit an idea just incase there was something there that might have been over looked. Let me see if I got this right we've put a jacket of water around a fire to heat it up but the water prevents the fire from getting hot enough to burn efficiently. So to try to get the fire hot enough to burn efficient we then insulate the fire from the water useing fire brick which in turn defeats the purpose of wraping the firebox with water.
With that said the money spent will go towards my education. I have what I have and I guess I'll just have to make the best of it until this thing rots or I can move up. I whished I'd found this site prior to my venture. So I guess I've got probably 3 or 4 years tinkering, cutting a lot of wood and reading this forum before I make a decision on where to go from here. Thanks guys

A bit more info for you.
I started to get a little worried myself, after reading a few of the comments. A farmer down the road has built two of his own so I gave him a ring. He took a 4x8 sheet of 1/4" plate and had it rolled, he welded it up and that's the fire box and then did the same thing again around the firebox and that was the water jacket, 200 gallons. His brother in-law, an HVAC professional and engineer said it would never work. This is the eleventh winter and would actually like it would fail so that he could build another, with a few improvements. He heats the farm house and a large shop. The flue is at the bottom rear and goes through the water jacket and then 15' high. One of his challenges is keeping the water from boiling so he has it circulating non stop into the shop floor once it reaches 185*. I'm going to pay him a visit and get a few ideas, I'm at the water jacket stage in my project. I'd like to hear more about how your project is going and what mods you're thinking about.
btw, he used rust inhibitor for the first 2 years and then stopped when he heard that it can do more harm than good if you're not testing the water regularily. He keeps the water topped up and has it filled to the top during the summer months.
I hope that helps you a little.

 

[brad068]

Rotaxman, I myself built a boiler. It is based on the garn design. It is starting its third year with no problems other than a few broken firebricks. If you have the room these boilers are one of the best options in my opinion. Maybe I can suck in another to our garn cult. %-P https://www.hearth.com/econtent/index.php/forums/viewthread/11262/

 

[sdrobertson]

The flue is at the bottom rear and goes through the water jacket and then 15' high.

The placement of the flue has everything to do with how long the boiler will last...fine line between any efficency gain vs boiler rot out.

 

[benjamin]

Dude, why don't you just build your gasification boiler INSIDE that beast?


Seriously, get some firebrick, build a reasonable sized firebox to actually burn the wood, and you'll have plenty of heat exchange if you can get your combustion temp to where it should be as opposed to the typical smoldering mess inside a barrel of water.

It only gets complicated if you want to be able to idle it.

Obstructing that flue would be the last thing I would do.

2cents from another (rank) amateur

 

[carpenter383]

I know this post is a couple months old, but this is the same boiler design I'm using.
I bought mine used, it had 1 season on it.
I added a baffle at the back of the firebox, some firebrick on the bottom, and I put a s/s insulated pipe with a cap on it.
I added a manual flue damper, but I'm still experimenting with it.
I put a magnesium anode rod in it.
I had issues with it boiling at first because of the strap on t-stat like shaver uses, but I'm using a ranco aquastat and it does good now.
I am happy with it, it heats about 2600 sq ft and keeps up fine with single digit temps. A full load of hardwood will go 12 hrs at around 10* outside and 72* inside. I don't heat my water with it though.
I haven't noticed any water dripping from the stovepipe at the smoke chamber (maybe because of the insulated pipe?), and I can't see where it has done any damage either, it's on it's second season now.
If I burn wet wood it will smoke somewhat, but if I arrange the wood to where the fan blows directly on the coals and use dry wood it doesn't smoke at all, you can just see heat coming out the stack, no smoke.
I use an average of aprox. 1/3 cord a week.
I like the idea of adding baffling to the smoke chamber, I might have to try that and see how it works.
My total investment including the boiler, pex, hx's, fittings, etc. is about 3 grand. If it only lasts a few yrs. it will still pay for itself, and I will still have the pex in place for the next unit.

 

[leaddog]

If you keep burning it hot that will help. The idleing is where you will get condensation dripping down the inside of the pipe and where that drips it gets with the creasote and causes a problem. When you shut it down for the season be sure and clean out the upper chamber and I would oil under the stack. It will burn off then the next fall but will help keep down any corrosion durring the summer. The baffle I had in mine was a water baffle and that tended to cool down the fire also which was bad.
leaddog

 

[carpenter383]

If you keep burning it hot that will help. The idleing is where you will get condensation dripping down the inside of the pipe and where that drips it gets with the creasote and causes a problem. When you shut it down for the season be sure and clean out the upper chamber and I would oil under the stack. It will burn off then the next fall but will help keep down any corrosion durring the summer. The baffle I had in mine was a water baffle and that tended to cool down the fire also which was bad.
leaddog

My blower is in the door and the baffle I added wasn't quite the same as the one added in the diagram. If I knew how to draw on a pic like was done in earlier posts I could explain more clearly. Basically instead of adding vertical plate off the back of the smoke chamber I added a 3/8" thick x 14" wide x firebox width plate that is horizontal and 2-1/2" to 3" below the bottom of the smoke chamber. My thought was that since the blower pushes the flame to the back of the firebox it would be most benificial to use a baffle to keep the flame from going staight up, it has to go around the baffle then up now. The creasote build-up in the firebox under the baffle is more flakey and brown than the rest of the firebox's creasote, so it definately runs hotter in that area.
I will oil the area under the flue pipe in the off season, this leads me to another question: Is it better to drain the system in the off season or leave it full of water yr round even when not in use? TIA

 

[hokiefan]

Any one out there with a deb design boiler that has no fan on it for draft. I am building one and used the central boiler designed draft way. Is it good to use water treatment in them as well?

 

[Gooserider]

Any one out there with a deb design boiler that has no fan on it for draft. I am building one and used the central boiler designed draft way. Is it good to use water treatment in them as well?

It is good to get the water tested, and decide on boiler treatment based on the results... The answer will vary depending on just what the water you are putting in is like, just what metals you use in the system, and so on. Probably doesn't hurt to treat most water, but exactly what treatment is appropriate will depend on the individual situation....

As to the earlier question about keeping the boiler full during the off season vs. draining - What I've seen suggests that if you have properly treated water, you are best off not draining. Might make some sense to float a layer of light oil on the water surface to keep down evaporation and minimize 02 absorption, but not certain.

Gooserider

 

[carpenter383]

Thanks gooserider for the reply to my question
I have treatment in my water and I like the oil idea. What affect would oil have on my hx/lines/pump if it found it's way into them?

 

[Gooserider]

Thanks gooserider for the reply to my question
I have treatment in my water and I like the oil idea. What affect would oil have on my hx/lines/pump if it found it's way into them?

It shouldn't have any effect on the pump or HX, but it might cause problems with the PEX depending on the sort of oil.

I may have spoken to soon on the oil idea, as I hadn't really thought about PEX contact. - I know several of the PEX data sheets caution against contact with petroleum products, so I'm not certain what the right kind of oil to use would be. I was getting the idea of using oil from the folks doing non-pressured storage tanks, which don't circulate and were using copper HX coils, so there wouldn't have been any way for the oil to come in contact with PEX in the system... This is one idea that should probably be put on hold unless we can get a more definitive answer about what is safe for PEX contact...

Gooserider

 

[carpenter383]

Ok thanks, I'll scratch that for now

 

[sdrobertson]

[quote author="carpenter383" date="1265019415] Is it better to drain the system in the off season or leave it full of water yr round even when not in use? TIA[/quote]

When you have shut it down for the summer, at some point the water level in the boiler will level off as there will not be much temp change. At this point I would add water till you have the entire boiler filled up to the vent. This will allow all the boiler treatment to cover all the internal surfaces and protect them. In the fall when you fire it back up, it will just vent the extra water out but you will have the protection over the summer when its not burning.

 

[carpenter383]

[quote author="carpenter383" date="1265019415] Is it better to drain the system in the off season or leave it full of water yr round even when not in use? TIA

When you have shut it down for the summer, at some point the water level in the boiler will level off as there will not be much temp change. At this point I would add water till you have the entire boiler filled up to the vent. This will allow all the boiler treatment to cover all the internal surfaces and protect them. In the fall when you fire it back up, it will just vent the extra water out but you will have the protection over the summer when its not burning.[/quote]

Ok thanks for the input, that's what I'll do