Hey all you downdraft gasifiers!

[boardmaker]

I have a question. I was looking at the woodgun and I am wondering. When the furnace has been in operation and is very hot, if it shuts down because the load has been satisfied, could the smoldering wood create an explosive situation? I'm thinking that even if you shut off the incoming draft and the fan, the firebox will fill with oxygen starved smoke. What happens when comes back on, say hours later? I noticed their website says it can burn chips. That seems like a great idea. I love the idea about downdraft gasification, but I'm concerned that it could get dangerous when shutting off and on or opening. Woodgun states that theirs can go into an idle.

Just curious.

 

[Nofossil]

The mixture in the top chamber is indeed explosive, but the system is designed so that it never has enough oxygen to actually explode. Opening the door when it's in that state is a bad idea, though...

 

[stee6043]

If these bad-boys were truly dangerous I don't think you'd see them becomming more and more popular.

Like nofossil says you don't want to open the door quickly when it's been sitting idle. Open the bypass, give it a second, open door slowly....

 

[ohbie1]

Use storage if you can and there is no idle time. You get to know how long a burn you need to raise your storage to the temp you want, and you also learn how much wood gives how long a burn. It gets pretty easy.

 

[chiefburritt]

The wood gun works as advertised. There is a bypass timer to allow you to fill the chamber or inspect it. After 20 - 30 seconds a light comes on to let you know you can open the door. Its an easy system to operate. I have no issues with mine. It's a top notch gassifier. BTW mine is fitted for steam, one pipe dry return, so I don't have the option of storage.

Oh yeah it will relight after hours of idle time and no access to oxygen...........

 

[Gooserider]

The mixture in the top chamber is indeed explosive, but the system is designed so that it never has enough oxygen to actually explode. Opening the door when it's in that state is a bad idea, though...

Note that many of the boilers come set up in such a way that you HAVE to open the bypass flapper, which is supposed to clear out that explosive mix and send it up the chimney, BEFORE you can open the door... This can cause problems in a few instances, and can be defeated, but mostly is a good idea... Of course, like any mechanical safety, it shouldn't be completely relied upon, and of course, the sole function of "idiot proofing" is the creation of improved idiots, but...

Bottom line - best not to open the top door while burning if possible to avoid it, but if you must, it can be done reasonably safely if one follows the proper precautions, including following manufacturer instructions.

Gooserider

 

[Fred61]

I have a question. I was looking at the woodgun and I am wondering. When the furnace has been in operation and is very hot, if it shuts down because the load has been satisfied, could the smoldering wood create an explosive situation? I'm thinking that even if you shut off the incoming draft and the fan, the firebox will fill with oxygen starved smoke. What happens when comes back on, say hours later? I noticed their website says it can burn chips. That seems like a great idea. I love the idea about downdraft gasification, but I'm concerned that it could get dangerous when shutting off and on or opening. Woodgun states that theirs can go into an idle.

Just curious.

The Wood Gun has a manual switch/timer that is activated by the operator to clear the chamber of gasses before opening the door and is left running while the door is open. I had a hood over the intake pipe on the outside of the boiler room to ease the ugliness of the air intake pipe and found it about 20 feet away from the house in the backyard several times when the boiler short cycled and blew back. I can only assume that after a moderately long idle, the gasses subsided and the coals were not as hot, the explosion wouldn't occur upon activation of the draft fan/damper.

 

[muncybob]

Hate to hi-jack the thread...but I'm about to start my 1st fire tonite in our WG. The manual states start the fire from the bottom of a paper/kindling pile, the video that came with the boiler says to start a top down fire...what have you WG owners found to be the best way?

Our WG has a large sticker that you can't miss on the front near the loading door that says NEVER OPEN DOOR UNTIL GREEN LIGHT IS ON! Wife knows tonight is the first fire and if there is 1 thing she has learned thus far it's wait for the green light!

 

[boardmaker]

So do any of you guys burn chips or any other biomass?

 

[Fred61]

Hate to hi-jack the thread...but I'm about to start my 1st fire tonite in our WG. The manual states start the fire from the bottom of a paper/kindling pile, the video that came with the boiler says to start a top down fire...what have you WG owners found to be the best way?

Our WG has a large sticker that you can't miss on the front near the loading door that says NEVER OPEN DOOR UNTIL GREEN LIGHT IS ON! Wife knows tonight is the first fire and if there is 1 thing she has learned thus far it's wait for the green light!

I always built my fires with the paper on top. If I had the unit today, I would experiment with small splits on the bottom, then kindling and then ignite it with a propane torch.

 

[chiefburritt]

Light it just like they said. However if this is your first fire don't build the fire to big for a while as to let the moisture come out of the bricks gradually.. I gave mine a couple of hours on a small fire that i kept feeding and watching as i was nervous how it would behave. Had no issues though. Once the bricks are seasoned your good to go and build a fire as you like. You should be very happy with the system. BTW post some pics.