Question regarding storage and pump

[Sizzler]

Problem is the main pump connecting the boiler and tank continues to run well after the tank is heated. This would seem to have a reverse effect on the system, since the boiler is now drawing heated water from the storage tank and that heat is lost up the flue and into the garage.

The pump kicks in at 65C and i don't believe it can be set to a higher temp.

Wondering what others have done to remedy this situation.

 

[steam man]

I assume your pump senses the boiler temp through an aquastat (or something similiar). The problem is the aquastat doesn't know what the tank temperature is in relation to the boiler. I use a Tekmar differential controller that is basically a solar controller to sense the differential between the boiler and the tank. I think mine is set so when the boiler is only about 6 deg above the tank the pump will shut off until the differential is much greater. That seemed to me to be the point of diminishing returns for my system. I realize there are a few different logic schemes that can be used. I would be interested in what others are doing.

Mike

 

[WoodNotOil]

Sizzler - What make and model aquastat do you have on it? Where is it positioned? Can you give a couple of details on your piping install etc.?

 

[machinistbcb]

I have been thinking about the same problem for my set-up. What I plan to do is wire in a heavy duty mechanical timer to the power feed to the boiler. I will figure out about how long it takes to burn a full load of wood at set the timer for that, I am guessing somewhere around 4 hours. This will kill the power to the pump and also the draft fan and also keep things simple so you don't have to add any extra controls.