hi i just replaced the two thermostats on my hot water system.not looking at where the wires were on the old one .one red one white wire.now the real problem when the upstairs zone is calling for heat it comes on and the lower
zone is off.bout when the lower zone comes on calling for heat both zone valves
are open and both get heat even though the thermostat on the upstairs
shows heat off.i have two honeywell model rth5100b thermostats and two
taco model #571 zone valves running off one taco model 008-f2 circulator.