Furnace and AC unit both coming on at the same time

Set up the new thermostat and have it set to heat. The furnace is heating, but the AC unit is also going on at the same time.

Welcome to the user-to-user forum, @bkramer1 !

For anyone to help you they would need to see how you wired it. Pull the thermostat from the wall and take a picture of the wiring, making sure the letter codes are visible. Then go into your furnace, and find the same collection of wire codes on your control board. Take a picture of that. Then, hopefully someone can recognize the issue.

Since you are a new user, while you are doing that I will have the Mods upgrade you so you can post pictures. :slight_smile:

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@bkramer1 I have bumped up your forum trust level so you should be able to post a photo now.


This is the current wiring at my furnace.

I removed the wires that were coming from the old thermostat. There was Y, G, R and W B/O. I had the C adapter hooked up with the Y goint to Y, the R going to R, the G going to G, and the W going to C.

I have an AC unit.

This was how my old thermostat was wired, which worked fine. Y, G, RC (with a jumper to RH ) and the white wire going to W B/O.

I guess we’ll see if someone can use those. What they typically do is compare colors with terminal designations, and you have a large blue tint on your furnace side, no colors on your thermostat side (no, the colors are not always the same as the terminal designations), and no picture of your Wyze thermostat wiring. Also your furnace side looks like power only, no control (but I’m no expert). So on the surface, it looks like it will be really hard to draw any conclusions on what is wrong.

We do have one guy who regularly works miracles on thermostat wiring though, I’ll call for him. @speadie :slight_smile:

Here is a pic of my wiring to the C adapter

And here is the wiring at my furnace. I took a white and copper wire off the C terminal that were there before, to turn the AC off.

Here is the wwiring at the thermostat.

The copper colored wire runs your humidifier. the white/black wires on C and Y usually connect the compressor outside to the furnace.

The wire colors on your C adapter are different than the wire colors at your thermostat, this leads me to believe that there is a splice somewhere.

Do you know for sure that you have a heat pump? I think you probably do not have a heat pump.
Try resetting the wyze and telling it you have the following wires on your old thermostat:

Rc (red wire)
W (white wire)
G (green wire)
Y (yellow wire)

It will tell you to hook up the C adapter.
It looks like you’ve hooked up the C adapter properly, please reattach the white and copper wires to the C on your furnace’s terminal strip.
Move the white wire on your thermostat from the O/B terminal to the W1 terminal. Leave all other wires on the thermostat where they are.

Your furnace board is from a single stage ICP gas furnace, so that makes it even less likely that you have a heat pump. If you can find the splice point in the wires, you can extend that blue wire to the furnace board and gain the ability to turn your humidifier on and off with your wyze.

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