I have an ST-2C master/slave control system with an oil-fired forced air furnace and A/C system.
I wanted to upgrade the zone 1 thermostat to a seven-day programmable thermostat that also had a programmable fan.
After talking to EWC (who are great, BTW), I settled on a White Rogers 1F95-1277
to replace a six-wire Honeywell.
This unit appears perfect: it has all the terminals, it's battery operated and it had the features I wanted.
But when it's installed, zone 2 operates even when the White Rogers is set to off.
The ST-2C bulletin explicitly says that when zone 1 is set to off, the entire system is disabled. And that's the way it works with the old Honeywell six-wire thermostat when it's on zone 1.
I thought I might have a short, so I insulated the wires with electrical tape before putting them into the subbase on the White Rogers. It still allows zone 2 to operate independently.
I've called White Rogers, who tells me they "aren't familiar with EWC and can't help." Plus, they think the system is a heat pump system because it requires O and B terminals.
EWC (again, they were great on the phone) suggested the short idea and had me confirm all the wires are correct on the control panel (they are) but also wanted me to get a voltmeter on the thermostat. (I wouldn't know what to look for.)
I am posting here hoping someone has gotten a White Rogers thermostat to work and might give me another clue to getting it to work on zone 1, which means in this case, being able to shut the whole system down when it's off no matter what zone 2 is calling for.