Automate whole-home humidifier with Remotec ZFM-80


I’m trying to control the 24v solenoid on my whole-home humidifier with a z-wave switch. I have a scene written that will check the outdoor temperature and indoor Ecobee sensors when the furnace calls for heat to determine if there is sufficient humidity in the house. If there is, it will not turn the switch on to run the humidifier.

The furnace control board has outputs on it for the humidifier - these outputs go to a 24v transformer. The 24v transformer then runs to the solenoid on the humidifier that turns the water on.

Normally, when the furnace calls for heat, the transformer receives power and the solenoid is triggered. When the furnace is finished heating, the transformer loses power, the solenoid closes and the water stops.

I’m trying to integrate a Remotec ZFM-80 into this scenario.

I assume I need 120v running to “F” (AC input) - I’ve tapped into the house main for that. The switch powers up and turns on and off fine through z-wave. How do I get this switch to control the solenoid?

I still want the furnace to continue to control when the humidifier goes on or off. What I want to do is put the switch between the 24v transformer and the solenoid so that if the furnace does call for the humidifier, I can decide to keep it off if the house is too humid.

That said, I’m a bit confused on how to wire this up to outputs “D” and “E” above (if necessary). Any help would be much appreciated!

Here are the two wiring diagram options they offer in the manual: