Charging tank timer

I use a timer to shut down the boiler and hx from boiler circ pumps when the boiler should have burned out its wood load. The purpose is to stop circulation of water when boiler water temp is less than tank temp. To continue to circulate would mix tank water, reduce stratification, and lose heat in the plumbing runs.

jebatty,

The boiler doesn't shut itself down? I'd think there was some mechanism that shuts the blower and circ pump down when the boiler temp gets to a certain set point.

I recently bought a $17 digital timer from Amazon to do exactly this. The boiler will "think" it's still burning as long as hot water is passing through the internal HX. If you're pumping 160 degree water off the bottom of your storage tanks and the fire is out, the boiler thinks it's still burning and will continue to pump.

Eventually I'll buy a Tekmar setpoint controller but I don't feel like spending $200 to make it work at the moment....

i use temp sensors and a three way zone valve to isolate my tanks from my boiler (when they hit my set temp) and keep the water circulating thru the wood boiler and the underground piping that in turn shuts my draft door but the circ keeps running until the boiler calms down or runs out of wood. if im home i add wood to the boiler a little at a time and watch my return temps so i know when the tanks are happy. that way i dont end up wasting wood. also i have another aquastat that makes my tanks a dump zone if i end up putting to much wood to my boiler.

So when the fuel load burns down, and boiler tank water temperature is higher than boiler water being circulated, you should raise the boiler aquastat circulator control to stop circulation right ?

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Yeah, but alot of the time you will not be around to do that. Like 2 a.m. in the morning or in the afternoon when your at work. Thats why you use a timer to shut it off for you. I use a mechanical timer, the type that is often used for pool heaters or water heaters.