Wyze Thermostat not Working with heat

Hey everyone! Not new to Wyze but I am new to the community!

Looks like this should be my first shot at fixing my issue.

Let me start by saying I am 99.9% sure I do not have a heat pump. I have an exterior AC unit and a natural gas powered furnace in my attic. I’ve attached images of my previous thermostat wire configuration and of my furnace’s prior wire configuration. I’ve also attached a pic of the furnace wiring after using the C-adapter.

My issue is this: it’s not turning the heat on. Here are some funky things to help you possibly diagnose: first, the outdoor unit is not supposed to run when the heat is on, but it does with the Wyze thermostat hooked up. The outside unit also turns on when I have the “HVAC” setting to “off” in the thermostat but the fan set to “on.” The only time the outdoor unit is off is when I set the hvac to off and the fan to auto.

As for wiring here’s some more info (Which you can see in the photos). In my furnace, the Y and W terminals have dual wiring (I transferred both wires from each to the c-adapter because I wasn’t told to do otherwise). Also, although there was no C wire in my original thermostat, there were two C wires hooked up to my Furnace control board. When I added the C wire from the C-adapter, I just added to the preexisting 2 (totaling 3 c wires in the c terminal of my furnace control panel).

Other than that, I’ve triple checked that all my wiring was good and still I have no luck. AC is running whether it’s on heat or not.

Any ideas?

When wiring the C wire adapter you only move the wires that are going to the thermostat. You need to leave the additional wires on the control board.



Thanks Ken! So, just to clarify, I would leave the extra wire in Y and W and leave both original wires in C, correct? So the final configuration would have two wires in Y, two wires in W, and 3 wires in C on the furnace control panel? And only one wire in each terminal on the c-adapter?

Also, any good way to determine which wire going to my thermostat? Cancel that, I’m dumb, I figured it out by the colors of the wires. Only outstanding question based on your advice is to confirm that the C wires that were already in the control panel should stay there with the new one from the c-adapter?

yes, leave those wires on C, you’ll be adding one from the adapter. the other wire on Y is going to your outside AC condenser, not sure where the other W wire would be going, but leave it there. You only want 1 wire per terminal on the adapter.

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That did it! I left those extra wires on the control panel and hooked up just one of each to my c-adapter and I’m getting heat no problem! Thanks man!

Good to hear!

Well… bad news. My furnace control board fuse blew. When I checked all my wiring, added a new fuse, and turned the system back on, it blew again. It did that 3 times. The thermostat worked for about 15 hours before the system tripped.

I looked at the c adapter and noticed that the c wire appears a bit grey, almost like it got too hot for a while. Not sure if there’s a way to figure out why this is happening or if there’s a solution. If not I’ll have to return the thermostat, which I don’t want to do. Any ideas?

I’m not using the C-adapter so I have it in my lap and can tell you that the C-wire coming out of the adapter is grey, so that is as designed. It does sound like there is a short somewhere, as if the C-wire is touching one of the other wires somewhere. From what I understand, you disconnected the wires that should have remained on the control board. Is it possible that when you moved them back the copper part sticks out and creates a short somewhere?

Damn, that sux. If it’s not a wiring/short issue it’s possible it could be the adapter. Do you have your original thermostat to verify the system is working without blowing the fuse?

Yes, actually it works fine with the old thermostat. I’m not the best with electric work, so I had to have a heating guy come out ot diagnose the fuse issue initially. $75 out the window haha. But, he was cool and helped me rewire the old thermostat, test the system, and then rewire wyze and test it and the fuse would blow every time. We confirmed all wiring was correct and no wires were touching.

I’m thinking bad c-adapter, as well. I’m going to have to call wyze and see if they want to help. At this point, my $49.99 thermostat has cost me $125 + a box of fuses and a few very cold hours haha.

any possibility of running a new cable to eliminate the adapter?

Unfortunately, that’s a bit of a job. Not a straight shot to the furnace from the thermostat.

So we thinking maybe a bad c adapter? I don’t want to give up on it but it’s getting annoying haha.

Chances are that there is something going on in that C-adapter yes. I’m pretty sure that when you call, Wyze will be happy to replace it.

Show a picture of your current wiring on the furnace with C adapter. Preferably a wide enough shot to see what that other component on W is doing.

The other component on W is going to a “dampener” I was told by the heat guy who came to service the furnace. As for the wiring, I don’t have a great pic of the wiring hooked up to the c-adapter, unfortuantley. And it’s not hooked up now. However, after taking it in and out 4 times, two of which were with a professional heating guy, I feel confident that I wired it correctly. It did work for over 12 hours, after all. One wire into each terminal of the c-adapter, and each wire coming out of the adapter was adding to the appropriate terminal on the control board.

At this point, if you’re confident in your wiring and want to troubleshoot whether the adapter is bad or the thermostat, I would reinstall the thermostat right at the furnace with a short piece of wire without the adapter and see if the fuse blows. If all good, delete the thermostat, start over with the adapter. If it starts blowing the fuse, then you know it’s a bad adapter. Contact support for a replacement.

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