How does a Wood Gun snuff out the fire?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

willworkforwood

Feeling the Heat
Jan 20, 2009
465
Central Ma
Here's a question for the Wood Gun guys, but it would also be interesting to hear from folks with other boiler makes (those having storage will probably not know anything about this :p). The WG is apparently able to stifle combustion in the firebox very effectively, by cutting off air flow. Don't know if it's 100%, but not, it must be fairly close. I have a friend who's owned a WG for 25+ years. He frequently burns poorly seasoned wood, and also runs idle-mode continuously throughout the heating season. In all those years, he's had no creosote, chimney, or boiler problems. If I tried to run my EB like he runs his WG, I would be taking out creosote in 5 gallon pails. Based on his many years of successful operation, and what I've read from the WG community here, it's obvious that they have a better mousetrap in the area of keeping combustion to a minimum during idle. Seems that the difference must be that a boiler such as my EB is allowing some air flow thought via the fan P/S openings, and the WG is somehow stopping that from happening. Not saying there is a huge amount of air passing through my boiler, but enough to keep it simmering for a period of time. So, does the WG have some kind of flap or damper which kills the air flow? If not, is there something about the design of the fan, P/S openings, HX, etc. which inhibits free flow of air?. But regardless of how the WG works, it's puzzled me that all of the other makes didn't incorporate that same operational feature into their boilers.
 
On the back of the Wood Gun there is an electrical actuator that opens and closes the air inlet door. The air inlet door has a rubber gasket on it and when closed this stops all air from coming into the burn chamber when the boiler shuts off. When the boiler turns back on, the actuator opens the air inlet door and the fan turns on and blows a good amount of air into the fire box. This air starts the embers up that have been kept hot in the firebox.
 
On the back of the Wood Gun there is an electrical actuator that opens and closes the air inlet door. The air inlet door has a rubber gasket on it and when closed this stops all air from coming into the burn chamber when the boiler shuts off. When the boiler turns back on, the actuator opens the air inlet door and the fan turns on and blows a good amount of air into the fire box. This air starts the embers up that have been kept hot in the firebox.
I hope Gasifier doesn't mind but I'll edit his post a little. All of the openings to any part of the boiler are sealed with a silicone type gasket. They really get all of the air sealed off (providing the gaskets are all in good order). And the air, when the blower is turned on, is being pulled down through the firebox, into the refractory passages. The actuator is a common Honeywell unit, (normally closed) motor/gear driven, spring close.
 
On the back of the Wood Gun there is an electrical actuator that opens and closes the air inlet door. The air inlet door has a rubber gasket on it and when closed this stops all air from coming into the burn chamber when the boiler shuts off. When the boiler turns back on, the actuator opens the air inlet door and the fan turns on and blows a good amount of air into the fire box. This air starts the embers up that have been kept hot in the firebox.
Now I recall reading a thread some time back about repair or replacement of that gasket - now I know what it's for. Don't know how many other boilers have something like this built-in, but it certainly seems to not have a downside, aside from wearing out or motor failing and needing repacement. A small amount of air results in the smouldering combustion that has zero benefit, so why not shut off air completely during idle?. Thinkiing about this further makes me want to run a few experiments with my boiler;. It would be very difficult to retrofit an actuator like the WG uses, but a couple of other possiblilities come to mind. If anything comes out of this, I'll post a follow up.
 
so why not shut off air completely during idle?
With a good air shut off I've gone to just shutting down completely when storage temperature maxes out. Rather than idle, just turn off the air, shut down the fire, and use the resulting pile of charcoal to start the next fire.
Thinking about this further makes me want to run a few experiments with my boiler;. It would be very difficult to retrofit an actuator like the WG uses, but a couple of other possiblilities come to mind.
Here's what I came up with that has been working well for two seasons. Simple, economical, effective, reliable, and easy to retrofit. It's just a damper valve connected to a lever arrangement driven by a Taco 550 series heat motor.

It's part of a closed-loop flue temperature control. For on-off control just need 24VAC to open the valve. Fail-safe closure by gravity.

--ewd

000_0030.jpg000_0035.001.jpg
 
I hope Gasifier doesn't mind but I'll edit his post a little. All of the openings to any part of the boiler are sealed with a silicone type gasket. They really get all of the air sealed off (providing the gaskets are all in good order). And the air, when the blower is turned on, is being pulled down through the firebox, into the refractory passages. The actuator is a common Honeywell unit, (normally closed) motor/gear driven, spring close.

O.P. So, does the WG have some kind of flap or damper which kills the air flow?

Silicone smilicone. Gasket on door. Door closed. Air stopped. Door open. Air goes. Fire. :ZZZ Pulled down through. Whaaaaateeevvvvver. ;lol

Thanks for the clarification 711.
 
...
Here's what I came up with that has been working well for two seasons. Simple, economical, effective, reliable, and easy to retrofit. It's just a damper valve connected to a lever arrangement driven by a Taco 550 series heat motor.

It's part of a closed-loop flue temperature control. For on-off control just need 24VAC to open the valve. Fail-safe closure by gravity.
--ewd
Very slick setup there EWD - you're running way out in front of the pack as usual! Thanks for sharing that, and when I pull the fan a few weeks from now to consider the possibilities, I will definitely keep in mind what you did as another option.
 
Status
Not open for further replies.