said by alphapointe:
I think I have this figured out, as the guy who takes care of the boilers for us tells me that the circulation pump only runs when the boiler fires, and that its' wiring is accessible. He says "drop a 120v relay across it, and you got your closure"
If it has zone valves they proably have contacts that turn on the pump. Some have aux contacts. You could use those or monitor the 24V signal to them. Would also give you info on what zone was calling for heat.
I would probably monitor the outputs of the thermostats through an opto..--
Embedded Systems Consultant,
SHDesigns home - DIY Welder