* terminal and RH for Humidifier

[Stevelom]

I am adding a humidifier to be controlled by my nest. Presently there is not a wire on RH or the * terminals. I noticed a separate transformer is powering the solenoid in the humidifier.  My meter is showing 28 or 29 volts. 

Do I run the transformer power through RH and then a 2nd wire off the *terminal back to the solenoid? So the * terminal acts like a relay switch? One-off to complete a power circuit.

Last night after watching a video telling me to  connected 1 wire from the transformer to the

* terminal only.  He explained RH was power from the furnace control board. I do not have a wire on RH.

[Stevelom]

I have an AprilAire Model 700M Humidifier and a Model 60 Humidistat I am replacing.

[GabrielaG]

Hi Stevelom,

Thanks for reaching out to the community. I am sorry to hear that the thermostat does not have a wire on RH or the star terminals and separate the transformer powering the solenoid in the humidifier. I will do my best to assist you right now.

To get a better understanding of the situation, please help me out by answering the following questions:

• What type of Nest Thermostat do you have?
• Have you done some troubleshooting steps? If so, can you list them?
• Can you please send me a picture of your current thermostat wiring?

Any additional details you can provide will be helpful.

Regards,

Gabriela