Product review (2 stars): It did work ok, but not now
It did work ok for about 18 months, but not now. It quit working and it would show 24 volts to the water valve, but would not operate the valve. If you shorted out the terminals on the humidistat, the water valve worked fine. 24 volts at the water valve, but no current flow through the humidistat. The switch in the humidistat shows a high resistance when closed. Strange!
I can find no way to remove the internal switch for inspection and try to clean the contacts, so it hit the trash can.

I liked the simple construction and operation, but the switch should last almost for ever as there is little electrical load and only switches maybe once a day or less. Usually a micro switch will go at least million cycles or more.

Made in China so you can't expect much I guess. I am looking for a better humidistat.