buderus boiler dump zone

[Metallica21156]

My old wood boiler i never had a issue with since i was always home when it was on. If the boiler got to hot it would turn on my airhandler and use the house as a dump zone. That boiler was controlled by a combustion fan so almost instant shut down. Now this boiler is controlled by a samson valve so no power needed. My issue is im gonna be burning coal and so in the am it might still have some fire left. Ive already thought of to use a magnetic latch for if the power or over heat the chain will drop and kill the air. But my issue is if the power is out then my air handler wont work as a dump zone. So first is what should i use, a car rad or something else? also where does it need to be, above the boiler or same hight? I have 2 tees installed at the top of the boiler i was gonna use, both have 1" outlets. I also have a electronic acturator for power failer it opens.

 

[maple1]

You can use baseboard rads (a few of them), or cast iron rads. Not sure about the car rad thing. They should be directly over the boiler, and the higher the better. Pipe directly up to them from the top of boiler, return directly down to the bottom. Plumb them through a normally open zone valve - that way when the power goes out, the zone valve opens. You could (should) also tie the zone valve to an aquastat (break on rise) so it would also open the valve (and start a pump if the zone valve end switch was tied to one) if things got too hot when the power was on.

Might also consider changing the sampson to a motor actuated damper that would close on power outage. Although I have no experience with a sampson or burning coal. Even when done right most dump zones will have their hands full handling a fire that wasn't dampered down.