Thermostat wiring issue - simple two wire system

Hi I just received two Wyze Thermostats, and when I tried to set it up, the app keeps saying my system is not compatible. Very simple two wire (red and white) heat only furnace, to which I have several Nest Thermostats working fine. Regardless of whether I choose R or Rh or Rc with W1/W2, I get the message that my system is not compatible.


If you have an extra wire for C that is powered, then it will work. I am not sure if the C wire adaptor works with a 2 wire system.

The wyze is not compatible with 2 wire systems. You need at least 3 wires.

Wyze long time customer time to get to work shorten your holidays this thermostat is bad like bad bad you need more help engineering wise because damn

I have a white red yellow and blue and it says not compatible please help. Or do I need to return ?

Why do you have 2 wires going to the red terminal? If you felt comfortable opening up your furnace, it would be helpful to see your furnace board. It might be possible to connect the wyze to your setup, it depends on how the wires are connected in your furnace

Just two wires. White and red. I have multiple zones all wired the same way

Also watching this. I have a 2-wire system that was connected to an old Honeywell circular dial mercury thermostat. I can’t believe Wyze didn’t include any instructions with how to convert, if it’s possible. Big Wyze fan, but they dropped the ball on this one.

Wyze thermostat does not support 2 wires. you need at least 3. (power, common, and switched)

Thanks for the reply. Correct me if I’m wrong here:

Nest, at least, and other smart thermostats support 2 wire setups (based on what I see on youtube).

I would need to pull a three-wire in order to use my thermostat.

Are both of those correct?

Yes. the nest has an internal battery that it recharges when the furnace is not on, from what I understand.
The wyze does not have this feature.

Got it! Thanks again. I’m familiar with electrical and many trades, but low voltage I’m not as familiar with.

My t-stat is only controlling a hydronic boiler. AC is on a completely difference system and will stay that way.

Is my only option to pull a C-wire to my boiler, or can I somehow use the Wyze adaptor or repurpose one of my two wires?

Unfortunately, you would need to have a third wire, so feeding a new wire would be your only real option to use the wyze.

Not a problem. Pulling wires is no big deal for me, so hopefully a relatively easy fix. Planning on just using the old ones as my wire-puller for the new one. Thanks!

I also have this configuration on a Lux programmable thermostat. Can’t we just mirror the same thing on the Wyze? White wire to W, then Red wire to RH on Wyze…, Then the same jumper wire that is shown here connecting the RC and RH? Seems like this should work on this one too. I don’t know. Came here hoping to see that others have already done or not.

The wyze does not use a battery, it only gets power from the wires connected to it, so if there are only 2 wires, when the wyze connects them together for a call for heat, it would shut off due to not having power anymore. Therefore, the wyze requires a minimum of 3 wires, 2 to power itself, and 1 to do something useful

Thanks Speadie for the information. That helps me (and likely hundreds of others) understand the difference between this and my existing programmable thermostat. And more importantly why this new product won’t work on my simple two-wire heating system.

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Totally. Thanks from me too. Got my problem resolved and pulled that third wire way quicker due to your helpful info for understanding. Cheers.