Product review (1 stars): Poor quality Chinese part
Same issue as many others.  After only a few months, the unit quit working.  The switch will click, but the circuit will not close so the water valve will not open up.  I took the unit apart and tested it with my ohm meter. I can manually move/squeeze it and get the circuit to close but it is not consistent and will not stay closed.  This was my 2nd unit to fail in the same manner.  Since this is attached to the duct work, if I switch brands, I would have to modify the opening so, for the sake of simplicity, I will replace this with another 4655 one last time and see how long it lasts.