Humidifiers and Dehumidifiers - aprilaire solenoid troubleshooting

My Aprilaire 440 stopped delivering water some time ago. I found the saddle valve was not delivering water, replaced it, and confirmed water is now delivered to the solenoid. Still no water to the tray. When activated, the humidistat clicks, but the humidifier solenoid does not click. The furnace current sensing relay delivers 28 VAC to the humdifier. I figure that I need a new solenoid. I have two questions. Do I also need to address the furnace relay which, as I understant, ought to be delivering 24 VAC? Second, did the solenoid go bad because A)the saddle valve stopped delivering water B) the furnace relay delivered too much voltage or C) Who knows.

Did you check to see if you are getting 24 volts to the solenoid valve?

If you are getting power to the valve, have you taken it apart to make sure if clear of lime build up?

if it's clean then may need a new solenoid valve.

I see 28 VAC at the solenoid. I was relying on hearing a click, and not hearing a click, I figured that proved the solenoid was bad. Before I buy one, I'll take your suggestion and check it for lime buildup. But isn't listening for a click and not hearing it the point at which one decides they need a solenoid?

There is a pin in the valve, and if there is lime build up, it won't move. the moving pin makes the click sound.