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I am currently using Honeywell thermostats that are 35 years old. The round ones with the mercury bulb in them. they have three terminals R W Y. The R and W go to the R and W on the Caleffi ZVR 104 Relay zone valve control. The W was never used.
I am wanting or thinking about going to the Honeywell RTH111 Series non-Programmable thermostat. That thermostat takes two AAA batteries. Or it can be wired for 24 Volts. I would like to wire it for 24 volts, but no where in the directions that came with a RTH111 thermostat that I bought 3 years for my air conditioner says how to wire in 24 volts.
I am guessing that if I connect my R and W to the R and W in the RTH111 and put batteries in the thermostat everything would be operational.
I have wired in a separate 24 volt transformer for another use. I am wondering if I can take the 24 volts from that transformer and power up the RTH111 thermostats, if so, how do I do that? If I can do that would the 24 volts damage the Caleffi ZVR104 Relay?