We are forbidden to attempt to assist with DIY attempts by homeowners. If you used a professional then call them back, if you've actually attempted this yourself, then call NEST. Sorry

 

I don't think the Nest can control a humidifier. It's one of many things those crappy thermostats can't do for the money they charge to buy them.

 

Nest cannot control your humidifier. It can hardly control itself.

 

I guess I should rephrase my question. Even with the old thermostat, there was no H, HUM wire etc., that seemed to be a connection for a humidifier. In that case, how did the humidifier know when to operate? Are most set to operate automatically when the furnace runs and turn off otherwise?

 

No, the humidifier needs to operate based on indoor humidity. Not just whenever the furnace runs.

 

Most have a humidistat mounted on the furnace duct system some place.

 

Most stats DON'T have humidifier terminals.

 

Gotcha. That's what I was wondering. Thanks!

 

This is off their website:

The 3rd generation Nest Learning Thermostat can control:
Heating: up to three stages
Cooling: up to two stages
Heat pumps with auxiliary and emergency heat
Fans
Humidifiers
Dehumidifiers

 

:D: :D: :D:

 

I have gen 2 controlling my humidifier. It is not the greatest control as you cannot set an actual humidity. As noted call nest and it is likely not a diy setup as adding a relay and control wiring is almost always necessary

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Ok good to know. I'll get ahold of an hvac professional and have them look into it. I appreciate your help