I’m seeing a bunch of posts about multiple systems and multiple zones, hopefully this will help clear it up a bit. I have over 5 years in the HVAC industry for Residential New Construction and Service/Maintenance.
***NOTE: This does not take into account your current system wiring.
Furnace ONLY - 4 Wires - Typically (R,B,W,G)
Furnace with A/C - 5 Wires - Typically (R,B,G,Y,W)
Air Handler with Heat Pump - 6 Wires - Typically (R,B,G,Y,W,O - Reversing Valve)
There is no industry standard for thermostat wire coloring!
Below is a good example, keep in mind some may have up to 8 wires for additional stages of heat/ac and indoor/outdoor temp sensors.
Red = 24 VAC Power (Required to power the stat)
Blue = 24 VAC Common (Required to power the stat)
Green = Fan
Yellow = A/C
- Stage 1 Heat
- Auxillary Heat
- Emergency Heat
Orange = Reversing Valve (some manufacturers energize in cooling, some in heating)
Multiple Systems (More than 1 indoor/outdoor unit):
You will need 1 thermostat per system. You can mix/match thermostats between the systems as they do not connect to one another. Example: 3 systems (3 separate units indoors/outdoors). Install a Wyze on the first and second systems, install a generic on the third.
1 System w/ Multiple (1, 2, or 3) Zones:
You will need 1 thermostat per zone.
If you have 1 indoor/outdoor unit, with 1 thermostat per floor, you will need 1 Wyze stat per floor.
***You can mix/match thermostats as they are wired independently to the Zone Board.
Multiple Systems w/ Multiple Zones:
Same as the previous example, 1 thermostat per zone per system.
As with anything, all HVAC installations can very. If you have a setup other than what I’ve described, feel free to reply and I will do my best to help.