Power failure on a gasification boiler, what happens?

[gdk84]

I have been looking at possibly installing a Heatmaster G series boiler next year. I am a wood stove guy, due to the simplicity and the off grid operation. However, my needs have changed and I am in need of heating more than one building as well as domestic hot water.

My question is, what happens when the power goes out, as far as the fire is concerned? I know these things have blowers and electronics to control the fire. I do have a manually hooked up gasoline generator that will run everything but I am not home during the weekdays. For example, there was a random power outage the other day early in the AM. Was offline for about 2.5 hours, I didn't bother firing up the generator because I knew is was an isolated outage and would be back soon. That got me thinking about a wood boiler and electricity as I was laying in bed..

 

[Bad LP]

Powerless dump zone opens into a gravity system located directly above the wood boiler. The zone valve for this zone is a normally open valve that closes when energized from the circuit feeding your boiler

 

[jebatty]

For me, boiler simply shuts down. Draft fan is off, fire quickly dies down. Run a test on your system by cutting power and observe.

 

[maple1]

Different boilers & systems would act differently. I suspect most forced or induced draft boilers would just shut down as just mentioned. They would keep generating some heat though, as the insides would presumably be heat soaked. Maybe with quite a bit of heat. So there might be some desire to have the circ on a UPS or the like - depending.

My boiler is natural draft, so it just keeps on burning wide open until the fuel is all gone when it loses power. I have a UPS I can plug my loading unit into, the loading unit will let convection flow happen to storage when it loses power, and I have a dump zone that can dump heat from the boiler to my upstairs zones. Redundancy is a good thing.

Is this to be an outdoor unit? That would likely hamper doing the dump zone thing, if so.

 

[Hydronics]

Same deal for me as Jebatty, if the power goes out the blower shuts down and the fire pretty much goes out. As stated, if it's indoor a normally open dump zone can transfer excess heat created by draft.
Can't beat the simplicity of a wood stove. Can't beat the controllability of a wood boiler.

 

[SuperSpy]

By CB unit has air control valves that are basically plugs suspended against a spring by a stepper motor over the air inlet. When the power goes out, the motor stops fighting the spring and the valves close.

I'd assume most units with air control would have similar systems that hold the doors open against gravity or a spring when calling for heat, so that an unexpected loss of power (or a control failure) would snap closed instead of open.

 

[salecker]

I have storage with my Econoburn
Power goes out,fan shuts down,fire goes out any heat soak goes to storage.The laws of thermodynamics keep circulating without power.Storage acts as a dump zone for any heat generated after power goes out.
We had the power go out about 1/2 hour after loading one night,no issues at all.

 

[gdk84]

Thanks for the replies everyone. Very helpful, and yes, I am looking at a outdoor unit. The Heatmaster apparently has a spring loaded damper door that will close shut with a loss of power. Doesn't sound like it's a big deal, other than a smoldering fire and some smoke.

 

[SuperSpy]

Better to prematurely kill the fire than to boil over and ruin the boiler.

 

[gdk84]

Better to prematurely kill the fire than to boil over and ruin the boiler.

Yes, exactly. That was what I was most concerned about if I was to be away. It's an expensive investment to have damaged by an overfire..

 

[SuperSpy]

It was about the first thing I tried when the dealer finished installing the unit. I stood outside and had my wife kill the breaker on the boiler while it was firing. First thing I heard was the two control valves snap shut.

 

[Woodfarmer1]

My Garn is an open system so it may boil over, the smoke would probably fill my shop. Powered draft fan with a horizontal chimney exhaust.
I ran it a couple years ago during an ice storm where we lost power for 3 days wth a small Honda generator.

 

[Dutchie84]

would a boil over cause damage to an open boiler like the G2? Or does it mean you just get water on the ground and have to top it up again when it cools down to normal operating temp?

 

[SuperSpy]

It depends on how bad it is. The steel isn't meant to get super hot so if the unit runs dry or it's boiling really hard you can overheat the steel causing it to warp or crack welds. Eventually the unit will get hot enough to start melting insulation off of wires powering sensors and control equipment.

 

[Bob Rohr]

Also be aware when you open the door on an oxygen starved firebox.