downdraft wood gasifier questions

[ginvt]

Hello All. I will start out saying my goal is to get 8 hours of burn. Sleep is precious. I am trying to figure out if I just scored big or if it is the next craigslist blooper!
This afternoon I pick up a 4 year old cleanwoodburn big bear 90k btu. outdoor or inside. Never heard of it? No small wonder. They were a small maine shop that as far as I can tell made about 50 units and the news a few times then closed. I am at the point of wanting to search down the builders to ask them questions!
I read on the web that the bb are ceramic lined. It has huge molded burn brick walls at the bottom sides and rear but the sides of the chamber just look like steel and warped at that. Is the described ceramic just the lower section? Remember it is a downdraft. I plan to build a guard to protect the rear lining since there is no way to buy them. I also read it came with a either 10 or 20 year guarantee. Not much good now.
The big kicker is this is to replace my 80's hs tarm wood oil combo. We installed it this fall and it is not working out for me having to feed it every 3-4 hours. Sorry tarm folks. It is mostly the burn chamber size. The bb has a huge door and burn chamber. The guy said they filled it twice a day. I guess my biggest question is can I just stick this in place of the tarm?
The bear has no gauge and I started wondering if it could be run in a pressurized system or if it has to be a open type?
The layout is a small modine in the shop and underground lines to a big hot air plenum mounted exchanger. The shop calls for it's circulator and the house is full time. I supplement with the house oil furnace helping to heat the water. I know I will need a gauge. I do not even know yet if there is a built in blow off valve or not. Sorry for the long confused post

 

[flyingcow]

The builders weren't out of Millinocket, would they? Or do you know what town?

Sounds like something that i would not put in any kind of a structure, other than an unattached shed. Far away.

 

[Singed Eyebrows]

Hello All. I will start out saying my goal is to get 8 hours of burn. Sleep is precious. I am trying to figure out if I just scored big or if it is the next craigslist blooper!
This afternoon I pick up a 4 year old cleanwoodburn big bear 90k btu. outdoor or inside. Never heard of it? No small wonder. They were a small maine shop that as far as I can tell made about 50 units and the news a few times then closed. I am at the point of wanting to search down the builders to ask them questions!
I read on the web that the bb are ceramic lined. It has huge molded burn brick walls at the bottom sides and rear but the sides of the chamber just look like steel and warped at that. Is the described ceramic just the lower section? Remember it is a downdraft. I plan to build a guard to protect the rear lining since there is no way to buy them. I also read it came with a either 10 or 20 year guarantee. Not much good now.
The big kicker is this is to replace my 80's hs tarm wood oil combo. We installed it this fall and it is not working out for me having to feed it every 3-4 hours. Sorry tarm folks. It is mostly the burn chamber size. The bb has a huge door and burn chamber. The guy said they filled it twice a day. I guess my biggest question is can I just stick this in place of the tarm?
The bear has no gauge and I started wondering if it could be run in a pressurized system or if it has to be a open type?
The layout is a small modine in the shop and underground lines to a big hot air plenum mounted exchanger. The shop calls for it's circulator and the house is full time. I supplement with the house oil furnace helping to heat the water. I know I will need a gauge. I do not even know yet if there is a built in blow off valve or not. Sorry for the long confused post

Hi, Welcome to Hearth. Could we get some pictures? Do you only have 2 tappings on the boiler, inlet & outlet? Even if unpressurized I think it still needs a safety valve if there is a mishap, you might want to look again for it. Are you sure this is a gasification boiler? Randy

 

[tom in maine]

Sounds like you are referring to the Black Bear Boiler?

 

[ginvt]

Yes it is a black bear. I am interested in any info I can get to help get safely rolling. I would not hook it up without a safety blowoff. Is that what is behind the separate shed far away comes from?
Millnocket sounds right. A old wood mill town? Did these boilers blow up or what??

 

[ginvt]

I will post what will be the only black bear pics on the web tomorrow in the daylight. It is still on the trailer at this point. "in captivity" I like to call it. It is very big to be considered 90k btu. I am hoping I can make it work with storage?

 

[tom in maine]

They were in Millinocket.
I know they had some "buckling" issues. I am not sure what the specifics were.
They folded rather quickly. I seem to recall that some financing did not come through. I know there are others here who had more
contact with the principals and maybe they can help.
One of the owners is still up there.

Oddly enough, we share the same patent attorney. Their patent was denied.
And they were really heavy. If you don't know that, you will when you move it.

 

[ginvt]

I bet the buckling problem is the upper walls of the burn chamber. These are warped looking. I have my fingers crossed.

 

[ginvt]

Sh:t Another ? I missed. Two tappings. In, out, 8"chimney spot for the draft blower.
THANKS FOR THE REPLYS! PARDON THE PUN BUT I AM GETTING STOKED with this gasification concept!

 

[pybyr]

Welcome fellow VT-er! Where in the NEK are you?

 

[ginvt]

The builders weren't out of Millinocket, would they? Or do you know what town?

Sounds like something that i would not put in any kind of a structure, other than an unattached shed. Far away.

Could you please elaborate. This is some strong stuff.

 

[ginvt]

Been having loading trouble. Finally I got some pics up. I would really like to know if the sides had a ceramic brick layer all the way up?

 

[ginvt]

A couple that would not fit the other post.

 

[sparke]

Can you take a picture of the lower chamber? I am trying to figure out if your boiler is a true downdraft or if it is just a regular refractory mass boiler like mine. We do have a Black Bear user on the forum. He is mentioned in your other post. The refractory looks 20 years old, hard to believe it is only 3 or 4. I am on my 3rd season, my refractory still looks fairly new... I would love to know more about your black bear. Where is the heat exchanger. If it is a downdraft - the bottom chamber should be feeding the Hex down bottom and around the back. If it is a Refractory mass boiler - the heat exchanger is in the top of the firebox... Good Luck Hope the boiler works out for you!

 

[flyingcow]

The builders weren't out of Millinocket, would they? Or do you know what town?

Sounds like something that i would not put in any kind of a structure, other than an unattached shed. Far away.

Could you please elaborate. This is some strong stuff.

Just doesn't sound like anything i would want in a attached structure. I'll check, but i think my neighbor had one and couldn't trust it to run on it's own. And it seemed to eat wood like an OWB. I'll see if i can get time tomorrow. he's not using it, which tells me alot.

 

[steam man]

The builders weren't out of Millinocket, would they? Or do you know what town?

Sounds like something that i would not put in any kind of a structure, other than an unattached shed. Far away.

Could you please elaborate. This is some strong stuff.

Just doesn't sound like anything i would want in a attached structure. I'll check, but i think my neighbor had one and couldn't trust it to run on it's own. And it seemed to eat wood like an OWB. I'll see if i can get time tomorrow. he's not using it, which tells me alot.

I am not sure what not to "trust" and I know the boiler is very frugal on wood if operated correctly.

I know the poster "Maine" very well and he has a Black bear boiler that he uses everday. He has tweaked it pretty much like anyone else one here has tweaked their boilers. Some door sealing issues, etc. It is a true gassifier in all aspects. Nice blue flame. The main difference with this boiler is that it has a water tube heat exchangers as opposed to a jacketed type set up. I understand this boiler was responsible for forcing much of the emission standards for wood boilers in the US. The two guys who made these were invited to sit on the board responsible for developing the rules for new boiler emission standards. I don't think there was a US wood boiler maker manufacturing gassifiers at the time hence the patent try. When this thing got lab tested it virtually made a number of conventional boilers obsolete. A very large boiler manufacturing plant was interested in producing these but went belly up before it could happen. My take is that there is nothing "unsafe" about these, especially being a water tube exchanger. It probably can take far more pressure than a jacketed type. One thing I do see about these is that there is nothing that can't be rebuilt or fixed. The warping of the upper chamber over time to me is just cut out a steel plate and weld a new one in if needed. The casing sealing issues have to be addressed. No fancy controls as in todays gassifiers. I do think they were undercapitalized at the time, hence the rush to market. They did need a little more time to field test but obviously didn't get that far. I am considering getting involved with resurrecting these boilers in the future with upgrades/modifications. Who knows?

 

[tom in maine]

My recollection is that these use a Seton-like hx and the construction of the unit is mostly refractory, built like a downdraft unit.
Although I had seen the patent drawings, I did not recall the fact that the firebox was not water jacketed, which might explain some of the issues with the buckling I heard about.
If it is constructed mostly out of refractory, it could have the potential of buckling the outer skins. Would be nice to hear about the failures that occurred. What I had heard about failures is third hand.

 

[steam man]

I am not sure if it had that much more refractory than a standard gassifier. The buckling seem to be at the steel encased firebox, not the outer stainless skins which are insulated from the firebox, if that's what you meant. I think part of the overheating was sealing issues from the flap and front loading door which allowed some air to enter uncontrolled. I am not sure what thickness metal was used. I don't know of any failures per say besides some warping. The heat exchanger is what you call a seton-style as it has two headers with bent tubes.

 

[sparke]

I hope the heat exchanger is easier to get at and clean then a Seton style Hex...

 

[steam man]

I hope the heat exchanger is easier to get at and clean then a Seton style Hex...

This boiler has the heat exchanger underneath and bends to the stack outlet. I haven't heard much about the tubes getting dirty and what access there is to the tubes. I'll check on it. Keep in mind it is a gassifier as opposes to the seaton unit which was basically a creasote production machine.

 

[Grover59]

Hey it appears that there are a few misunderstandings on the Black Bear Boiler. First it is a true downdraft gassifier, it is no more unsafe as any other boiler like it. Yes it did have some problems, and one was the top chamber could get to hot. Because the boiler was insulated so well, it had now way of dissipating the heat from the top. Now I have been running mine since 2007 and I have not had a problem, however I don't need to run it balls to the walls like others may have, mine is in my basement and works well keeping my 1000 sq ft house heated and also my dmhw.
After the first year I built a 750 gallon water tank with wood and lined it with epdm, I consulted Tom from Maine before doing this he has done the same before. Now my reasons for the tank was to make the Black Bear Boiler run constant and therefore more efficient and it definitely did that. As you can see from my other post I really believe in heat storage, makes life much easier when burning wood. At this time my 750 gallon water tank is heating the house and the hot water and my Black Bear is down, I will start it tonight to bring my tank temp back up.
Back 3 weeks ago I had the inventor should I say of the Black Bear at the house, he happens to be someone I grew up with here in East Millinocket. Anyway he suggested taking all of the insulation out and letting the heat dissipate more easier, so I did and it appears to work fine, looks bad but works. I consider myself the king of mickey mouse, I will mickey mouse something together to make it work, I don't use fancy controls just basic crap, so here is how my boiler works, very simple.
Tonight I will go down stairs, open the top door, level what coals are in there, and open the bypass damper, then close the top door. Then open the bottom door rake out any ash from the previous burn. Then I will go set my manually timer I have screwed to the wall for about two hours, reach down and reset the relay that will start the blower, this relay is not something that comes with the boiler it is my mickey mouse stuff I was talking about. While the blower is running I then gather up some wood, some small pieces and then maybe 8 to 10 large split pieces. I take a look at the stack temp and it if is over 250 I will close the bottom door and open the top, at this time I should see a blue flame coming from the coals in the to chamber. I throw in the wood, close the top door, and then open the bottom still leaving the bypass damper open. I wait until the stack temp gets to about 400 and close the bypass damper, most normally the boiler will be gassifying, I know that is not a word but it should be.
I then close the bottom door and walk away all is good, the manually timer will time out in about two hours, this was to let the stack temp get up to 300 or above even when the timer times out the blower keeps going. As the stack temp goes down to around 250 to 275 I have a aqua-stat control with a probe on the stack it will shut the blower off at about 275, this is great cause it leaves me just enough coals for the next start up. I use to use just the timer but it would sometimes burn the wood and coals clean or shut down premature.
Stack temp is very predictable everyone should have a candy thermometer stuck in there stack, works great.

Steve

 

[steam man]

Hey Steve-you should have told the story with the coin timer you used. That would have sent the lambda control guys into a tailspin. LOL....

God knows I've seen him run that boiler like that and it works.

 

[sdrobertson]

Hey Steve-you should have told the story with the coin timer you used. That would have sent the lambda control guys into a tailspin. LOL....

God knows I've seen him run that boiler like that and it works.

If I remember correctly, that coin timer was in a post sometime in the past. I actually thought about that when I purchased a timer for my system

 

[Grover59]

Yes that timer is now in a campground in the North Maine woods, running a pay phone, Pittston Farms the logging farm back when they used horses to harvest wood to make paper 100 years ago.

It was the only timer I had and it worked, pretty cool that I had to put quarters in it to get my boiler to run.

Steve

 

[ginvt]

Hmm. You forgot to tell me that one Steve!

Thanks for putting your details up in the thread so future new owners will find some info. A lot of thread answers get received in pm's and end up not available to all for reference. Also thanks for all the phone time today. I feel like I have a real handle on this now and will have it in shortly after getting the blower. Until then I am going to open her up and clean the ashes/ soot out and give it a good look over!

What a awesome site this is! A big thanks to all for the instant welcome I got and abundance of helpful folks. Makes the net a very powerful and useful tool to harness my (new to me) cutting edge technology!