Zone valve and thermostat question

Unknown

my old buddy Crispy Chicken with a wiring problem . One Honeywell zone valve , when powered up , would not open . In fact , it stayed closed harder than the normal spring action . When the power was shut off it would open manually with the spring , like normal . Turned out to be a defective cheapo Rite-Temp thermostat , letting power run through it even with the switch in the off position . Took the thermostat off and jumped the wires and the zone valve worked fine .

Anyone ever have that happen ? Have a zone valve stay closed harder because of a defective thermostat ? We both thought it was the zone valve just being stuck , but changing the head and having the same problem proved us wrong .