U wire nest thermostat

[Nm86]

I’m trying to change from Honeywell to nest. Where do I put the U wire? It’s not listed in the app. 

[Markjosephp]

Hello Nm86,

Thank you for taking the time to let us know about your inquiry. I'd love to help.

Different thermostat makers may use the * (star) and universal (U, U1, U2) terminals to control the following:

• HVAC accessories (i.e., humidifiers, dehumidifiers, and ventilators);
• High fan speed in a multi-speed fan system;
• Third stage of heating or cooling in a multistage HVAC system.

Do you have a humidifier or dehumidifier? We strongly suggest a professional installation for these systems because incorrect setup, either due to miswiring or wrong software settings, can cause weird heating, ventilation, and air conditioning (HVAC) behavior and even damage the HVAC system.

Please let us know if you have more questions in mind.

Regards,

Mark

[Markjosephp]

Hey there,

I wanted to see if you still needed help. Please let us know if you have any other questions or concerns.

Thanks,

Mark

[Markjosephp]

Hi Nm86,

I'm checking in to make sure that you've seen my response. Please let us know if you have any additional questions or concerns before I lock this thread in 24 hours. 

Thanks,

Mark

[Nm86]

Hi, I’m going to get a pro to install. Thank you! 

[aatienza]

Hey Nm86,

Gotcha — let us know if you have other questions as I'll be locking the thread after 24 hours.

I appreciate the help, Mark.

Thanks,

Archie