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Nest thermostat compatible with whole house humidifier and two stage gas furnace?

Brwilliams4
Community Member

Hello, in researching I have found that the humidifier uses the O/B* connection,  but I was told the furnace W2 wire needed to connect there. It appears that I have no where to connect the whole house humidifier now. The other wires are G, W1, R, and C. This is not the Learning thermostat. The thermostat is working fine to control temperature.  Am I correct in assuming that I cannot now connect the humidifier?

1 REPLY 1

Markjosephp
Community Specialist
Community Specialist

Hello Brwilliams4,

It sounds like you're facing a wiring challenge with your humidifier and furnace. Let's sort this out!

Typically, the O/B wire is associated with the reversing valve in a heat pump system, and the W2 wire is used for the second stage of heating in a multi-stage heating system. If your furnace does not have a W2 terminal available, you might need to explore alternative options for connecting your whole house humidifier.

It's best to consult with a qualified HVAC technician if you're planning a wiring configuration change between your W2 and humidifier (* terminal). Keep in mind that the specifics can vary based on your HVAC system and the humidifier model, so it's crucial to refer to the manuals and seek guidance from a professional to ensure a proper and safe installation.

Let us know if you have more questions.

Regards,
Mark