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Humidifier help!

t_metze Member Posts: 1
I am in need of humidifier assistance. I have the Aprilaire 500 model whole house humidifier. I installed and wired the humidifier but when I turn it on nothing happens. Attached is how I wired it-which I’m assuming is the issue? Any and all help is very much appreciated. Thank you.


    EBEBRATT-Ed Member Posts: 15,622
    What do the 2 yellow wire go to? Humidistat? Air switch" Current switch?
    HVACNUT Member Posts: 5,864
    If I'm looking at it right, it seems correct.
    The humidifier terminal on the board powers 120v to the transformer.
    Common on the transformer goes to a yellow on the humidifier solenoid.
    24v on the transformer goes through the humidistat to the other yellow on the solenoid.

    Can you check for 24v at the solenoid or see if the transformer is getting power from the humidifier terminal on the board?

    You are aware the humidifier terminal is only powered during the heat cycle when the fan is energized.
  • Mike
    Mike Member Posts: 94
    Are you sure the hum terminal on the board is 120 volts?