Solenoid valve When the Humidistat is set at 45% and the furnace is on the circulating fan on the humidifier is working but no water is flowing through the solenoid valve.I hear the clicking when I cahge the setting on the humidistat. Could the solenoid valve is gone bad?

SOURCE: Humidifier control .

if humidifier was wired into thermostat circuit for power instead of seperate transformer , this can happen. you need to see if you voltage going to the solenoid valve. if you do , and it isn't opening, the valve is bad . this is assuming that it is using a # 50 relay to come on only when the fan runs . . make sure the water valve is open

SOURCE: water not getting to panel when furnace is on

I had a problem quite similar to this. It was the power connector. This is the 4-pin white connector that engages when the cover is removed/replaced when accessing the water panel.

One of the pins was loose in the connector thereby supplying intermittent 24 volt power for the solenoid that is powered by the fan motor control board transformer in the humidifier cover next to the fan motor (not seen unless fan is dissembled).

If you are technical such as I am this is easy to fix by removing the connector, removing the loose pin, and often each retaining clip on the connector pin can be bent out slightly, then replace the pin, and then it should be fine. Also, it's best to check this out on a bench while running the entire unit. You also might need to replace the entire power connector. Sometimes it's easy to think the problem is a defective solenoid or fan motor/transformer board, etc. It's frustrating, because sometimes the humidifier works perfectly, and then sometimes there is no water flow. Since I did this mine has been 100% OK.

NOTE: IF YOU ARE NOT TECHNICAL DON'T EVEN ATTEMPT TO FIX THIS PROBLEM, CALL IN A PROFESSIONAL TECHNICIAN. LETHAL VOLTAGES ARE PRESENT IF THE FAN CIRCUIT MOTOR CONTROL BOARD IS EXPOSED. ALSO, MUCH OF THIS IS FRAGILE. IT COULD
BECOME COSTLY IF YOU MESS UP.

SOURCE: Fan running but no water flow

the humidistat on this unit just acts as a set of dry contacts. with the humidifier plugged in, you should be able to touch the 2 brown wires by the water solenoid together and get the power fan to run and the water solenoid to enrgize. if you do this and water does not flow, you most likely have a bad water soenoid. it is either electrically bad, or just plugged with water deposits. sometimes you can pull it apart and clean it, sometimes you just have to replace the solenoid.

SOURCE: Solenoid won't open--voltage drops when connected to humidistat

The coil may shorting out the 24vac supply to the solenoid. Recommend replacing soleniod.
Normally you should be able to read the 24vac across the solenoid when energized.
The other option is to get a 120vac to 24vac transformer and test the solenoid. This way you will know if the solenoid is the cause or the 24vac source is the problem.

SOURCE: I have a model #560..turning the humidistat

turn the saddle valve in and back out. sometimes the small pin hole for the water gets plugged with something over the summer when the units aren't running and just turning the valve in and back out clears it out and allows the water to flow. check to see that you have water flow at the solenoid and if you do then it is probably the solenoid that is bad.