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Humidifier runs when set to on, off or auto

pete1989pete1989 Buffalo, NYMember


I installed my Ecobee last night and while testing I found the humidifier runs no matter if I set it to on, off or auto.

I have a Lennox forced air single stage gas furnace and Lennox single stage Air Conditioner as well as an Aprilaire 550 evaporative humidifier.

Previously, the himidifier’s solenoid was connected on one side to the C terminal on the furnace control board and the other side went from the Y terminal to the humidistat to the solenoid.

A “before” picture of the control board is: https://m.imgur.com/a/0GrXh

When I installed the Ecobee, I left the solenoid connected to the C terminal on the furnace control board and the other end goes into the Acc+ on the Ecobee.

Some pictures of the “after” on the control board, behind the Ecobee and the config screens are:


Thank you for any help or insight you can provide. I thought I did everything correctly.


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