Reply To: How many boiler zone valves to one thermostat

[Harold KestenholzParticipant]

If you run the power required to operate two zone valves through one thermostat you are on the margin of burning the anticipator or thermostat circuit.

With some tricky rewiring, you can run the second ‘slave’ zone valve motor off the end switch of another zone valve as is done with some of the 5-wire White-Rodgers zone valves. You would use the ‘end switch of the zone valve operated by the thermostat’ as a thermostat (which is a fancy switch) to the ‘slave’ zone valve motor. As it is a tricky wiring, you have to get it right the first time.