Thermostat U1 Wire

Hi community. My house is a month away from finishing and I would like to put in two Wyze Thermostats. I spoke with NEST, showed them my wire configs (as attached below) and they verified it would work. When I did the Wyze Thermostat compatibility checker, it did not show a selection or port for my U1 wire that I currently have in my dumb thermostat that comes with the house.
*all of the other wires I know are standard and look ok.

Anyone have any idea what I would connect the U1 wire with?

U1 typically controls either a ventilation or humidifier/dehumidifier but you should trace it to your control board to be sure. On a few occasions I have seen them wired to a heat/cool stage on a heat pump system.

Or check with an HVAC person.

Welcome to the Wyze community @daverosen5!
When you do the compatibility test, select the “I don’t see all of my terminals” then choose”other”.

Where does it show more info on “The thermostat can control 1 humidifier.”?
Looking at the install config video, I do not see a spot for U1 with the Wyze Thermostat.

The thermostat may not be compatible with your system. I’ll tag the expert,@Chuan to see if he can help you.

Thanks Brlepage. Looking forward to it @Chuan.
One thing to note, the upstairs AC does not have a U1 wire, only the downstairs.

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Do you have a humidifier or other external piece of HVAC equipment? Where does the wire go?

U1 wire should be placed in our * terminal, it is a not very common terminal so we did not have it in our checker, but we consider to add it if there are more cases appearing.


I’d recommend putting this information in the comparability checker and/or the the setup guide.

Wonderful, will install when I receive it in December and will put the U1 brown wire in the * terminal.

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So mine has a brown and orange wire going into U1. I know I can put one of them into * section but what about the other one?

I have the same thing going on over in Texas. Two U1 terminals. One goes in * but What about the other @Chuan can you help us out? Thanks in advance!

Might need a pigtail to wire them both to the same * connector if they are running 2 separate devices. This is the problem with lever style thermostat hookups, if you need to connect 2 devices to one terminal, you have to use a pigtail and wirenut, and hope that the relay in the thermostat can drive 2 devices.

Did this connecting two U1 wires on old thermostat into one * terminal work?

Hello, anybody can help me on where to connect the two cables connected to two U1 terminals of my Honeywell to the new Nest?

I have the same problem and don’t have idea where to connect them.