My old thermostat only has 4 wires (No C). I completed the install using the C-wire adapter. The Wyze thermostat does not come on. The wiring at the HVAC control board seems ‘standard’. The wiring at the thermostat also seems standard. The one catch is that my furnace has a sump pump with a flo…

Using the C-Wire Adapter, G needs to move to C on the Wyze backplate. The G wire becomes C. Give that a try.

Yeah, what he said. :slight_smile:

My wiring is the exact same set up. Mine runs the condensing unit and heat at the same time.

So you got it to work without changing how the condensate pump is wired in?

Yes the pump is wired to from R on the c connector trough the pump switch and back to the stat wire .

What do you do if your furnace doesn’t have a C label for the circuit board? I have G,O,B, W1,W2,W3, R,BK, T,Y,YLO. I don’t know where to connect the c wire to

Welcome to the community @dimashah ! Could you take a picture of your control board?

Thank you so much it worked!! You are guys are such a life saver!!

@Brlepage Hi, Let me know if this is the right thing. Thanks

Wyze Thermostat - Wiring Question

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dimashah December 26, 2020, 6:52pm 15

Will it work with my thermostat? It Honeywell TH9421C1004
There is no letters, just numbers 1, 2, 3

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Wyze Thermostat - Wiring Question

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