My heat will get stuck open or stuck off sometimes. I traced the problem to the zone valve and found that it sticks. I can remove the motor (when power is off) and the switch will close the valve again as soon as motor is popped off. I can replace the motor (with power still off) and the switch will then cycle the motor as expected. However, when I turn the power back on, I can push the switch to open but it stays there and will not cycle back down to AUTO where it should be. (I’ve already replaced the thermostat and also have the new one set to lowest possible.)
I should also add that the heat continued to pump out even when thermostat is disconnected from the circuit completely, hence my focus on the valve and motor operating it.
I took a video of the behaviour but I guess cannot attach here.
