If you look on the inside cover of the furnace, there should be a wiring diagram, maybe even two wiring diagrams. The simplier of the two will show the wiring connections for the control wires. It will show the R, W and G connections. Also look for a line with the C label. It will show where it runs to, quite possibly to a screw on the chassis. A few replies earlier in the thread I have a picture of the wiring diagram from my goodman furance. it is about 14 years old.
Welcome to the Wyze community @turner.dougp!
I have a similar setup. Look for a wiring diagram as @ndelviii suggested. I’d also suggest looking for the wire that comes in from your thermostat, it might be identified by the cable.
Look behind your current thermostat for a blue wire. It is currently attached to C in your furnace. It may have been pushed into the wall. You will not need the C adapter if you can find this wire and plug it into C. Make sure to tell the wyze that your “current” thermostat has a C wire when you do this.
I saw this and wanted to share this info about 2-wire systems because it explains really well how they work! Hope it eventually helps someone:
The most basic of systems (such as an older ‘heat only’ forced air / gas furnace with a standing pilot light) only need two wires for control. They connect to a two-wire thermostat (generally a mechanical thermostat with a mercury filled ball connected to a coiled bi-metal strip).
A basic two-wire thermostat can be compared to a simple single-pole switch that you will find throughout your home, only instead of you turning the switch on and off as required, a mechanical or electronic temperature controlled mechanism is the operator of the switch.
The terminals are usually marked ‘R’ and ‘W’. They usually operate at 24V ac power, and the source of this control power comes from a control transformer mounted either just outside, or inside the furnace body. The line voltage feeding the furnace (to operate the fan blower motor) is transformed down to a safer level of 24 volts (the gas control valve needs 24 volts to open), and after making a series loop through at least one safety device (the most basic and mandatory one is an over-temperature shut down), the power goes up to the thermostat, and when the room temperature falls below the set-point, the contacts close completing the circuit to the gas valve allowing it to open, the main burner to ignite, and begin the heating cycle.
In this the most basic of heating systems, as the temperature of the heat exchanger rises, another contact is closed on the line voltage side of the equation, and the fan blower motor starts moving air through the heat exchanger and out through the ducting in the home. If the fan fails to run for any reason, the heat exchanger will get too hot and the hi-limit temperature device will open the circuit to the gas valve, closing the valve and stopping the heat cycle.
I find this very informative so I hope someone else does too!
Thanks
DB
Well, there is indeed a blue wire tucked into the wall! Going to give this a go and update the group. Thank you for the quick … and good advice.
Well, finally had a chance to take a shot at this and no luck. Although I was able to locate a loos blue wire and then wire the Wyze accordingly … there was no power to the thermostat when complete so I removed the Wyze and placed the old thermostat. Still stuck.
Hmm. The blue wire might be broken or not spliced somewhere between the furnace and the thermostat then.
You could use the C-adapter, wire as follows:
Make sure to tell the wyze that your “old thermostat” has the following wires during setup:
Rc, G, Y1, W1
This will ensure that it turns on and walks you through setting up the C-adapter functionality.
Note that the green thermostat wire connects to G on the adapter and C on the thermostat in C-adapter mode.