motorized valve always open even thermostat is off?

Old 11-24-05, 02:20 PM
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motorized valve always open even thermostat is off?

Hi there, i have a mg water heater boiler.

I just noticed last night that one of my thermostat doesnt seem to be able to control the motorized valve. And the valve is alway open and so the boiler is alway on until operate temperatur are reach then it turn off again and so on.

I have four thermostat in total, other three are fine. But only this one in the living room that i cant turn off/on, kinda like its set at its own operating temperatur already.

Is this a problem with the thermostat or a motorized valve?

Old 11-24-05, 03:00 PM
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Zone valve

On the valve that is giving you trouble, mark each wire with tape & identify it as to the terminal to which it connects. Remove the wires & see if the valve closes. If this is a Taco valve, it will take at least a couple of minutes. If the valve fails to close, the valve is at fault. If it closes, re-attach the wires & repeat the process at the thermostat. If the valve closes this time, the thermostat is at fault. If it does not close you have a short in the wiring somewhere.

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