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Backing plate heating up

larryED
Community Member

Have a gen 3 Nest, working fine for years, Decided to connect a whole house humidifier to the Start terminal, after doing so the backing plate on nest starts to heat up, The Wire from the Nest goes to the humidifier then to com on the HVAC

1 ACCEPTED SOLUTION

larryED
Community Member

Found the issue, It was because the old 2001 Aprilaire 700 humidifier that the Nest was connected to was an older fan model, the fan relay circuit board 110v on the humidifier was back feeding into the nest causing the back plate to heat up, Replace the humidifier with an newer model 2021 Aprilaire 700M Whole Home Humidifier, Manual Fan Powered Furnace Humidifier, resolved issue! Works great customer very happy

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2 REPLIES 2

Jake
Community Specialist
Community Specialist

Hey larryED,

 

Sorry for the late reply. I wanted to follow up and ensure you are good to go. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further. 

Best regards,
Jake

larryED
Community Member

Found the issue, It was because the old 2001 Aprilaire 700 humidifier that the Nest was connected to was an older fan model, the fan relay circuit board 110v on the humidifier was back feeding into the nest causing the back plate to heat up, Replace the humidifier with an newer model 2021 Aprilaire 700M Whole Home Humidifier, Manual Fan Powered Furnace Humidifier, resolved issue! Works great customer very happy