this installation has a hot water boiler that has a mixing valve controlled by an Aquatrol device. also there are two alternating pumps that are on 24 hrs.

during warm days, its clearly not possible to turn off the conventional cast iron boiler but in light of the mixing valve, it should allow an option to shut off the pumps when mixing valve closes; interested in thoughts on this issue (boiler is controlled by a DX-9100 from Johnson Controls) - the pumps cost about $25 in electricity to operate and real dumb to leave them on when there is no heat demand.

the boiler has a circulating pump that effectively circulates water in a loop before it flows to the mixing valve.