Wyze thermostat black/power off all of a sudden

I’ve written up a nice article about how to get my wyze up and 10 months later it just crapped out. I tested the common wire and it has power. I power cycled my hvac just in case but nothing. It’s not on wifi and the screen is blank. Any suggestions? Here is my article I wrote: Installation of Wyze Thermostat on Multizone HVAC System (Ultrazone) | by Tom Nats | Medium

Did you see the Wyze screen when you power-cycled the thermostat?
Try holding down the thermostat knob to reset it.
If that doesn’t work, I would suggest contacting support ASAP.
By phone: (206) 339-9646
Or online: Wyze.com/support
Wyze Support has extended their live support hours for a better support experience. ( Excluding Holidays & Emergencies )
Monday - Friday 4 AM – 8 PM PT

Saturday 8 AM – 4 PM PT

Your “bad picture of your control board” is especially bad for troubleshooting, as it does not show the model number of the board. I’m assuming you have an ST2E?
Did you follow the instructions in your zone control manual for a tripped fuse?


Thanks for the replies. My board is here: http://www.ewccontrols.com/acrobat/090375a0115.pdf
what I don’t understand is I tested the C wire and it has power so I’m confused on why the Wyze thermostat doesn’t start up.

Ok, it appears I wasn’t testing the voltage correctly. I think something happened with my C wire for some reason as it’s not putting out any voltage all of a sudden. After 3 hours of this I guess it’s time to call in a professional…

When a polyfuse trips, it goes high resistance. Unlike an actual fuse, you may still see voltage between R and C when the polyfuse is tripped. The polyfuse will limit the current that can flow, however, preventing the thermostat from starting up. You should unplug the transformer connection like your manual tells you to do for at least 30 seconds and then try plugging it back in again.

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It turns out my board went bad. Having it replaced as we speak. @speadie thank you so much for your help and knowledge. There was nothing wrong with my Wyze thermostat. Again, thanks for taking the time to help.