I have just bought a house with an oil fired, hot water boiler. It has 3 zones, controlled by zone valves, one of them being for the Phase 3 hot water tank. When any zone valve opens, the signal from the aquastat to the Taco circulator is intermittent....sometimes there is power to the circulator briefly, sometimes not at all. If there is power to the circulator, I will hear a click in the aquastat after a short period and power stops to the circulator. Not being sure if there was a resistance issue within the circulator, I disconnected the wires to it. But the problem still occurs. I thought it was possible there was some type of "safety" within the aquastat which would kick in in case of excess amperage draw from the Taco. It has a Honeywell, but there are no #s on it. It appears to be an L8124....but I'm not sure if it's an A, B, C, or M. To top it off, the plumbing shop asked me if I knew the 4 digit suffix also. Does anyone out there know which is the correct Honeywell replacement unit I shoud ask for?

Thank you for any help,
Dave