Hi Dpj,
Thanks for reaching out to us and welcome to our community! I'd be happy to decode your wiring setup.
Just for clarification, here's what your photo shows:
- O: This is usually an auxillary heating wire, or a changeover valve that switches between hot and cool.
- R: The R wire is the power wire for your heating and cooling system. If you only have one R wire (no Rh or Rc), you can connect your R wire to either Rc or Rh on the Nest thermostat.
- B: Sometimes this is paired with the O wire, but it can also be a common wire (c-wire), which helps your Nest Thermostat charge. I would consult with a Nest Pro to ensure which wire it is.
- X2/W: This looks like your heating wire, but to the best of my knowledge, the X2 port is uncommon in use with the thermostats.
- Y: This controls your cooling system.
- G: This controls your fan.
It looks like it would support a Nest Thermostat, but needs a professional lookover to make sure its installation doesn't damage your HVAC system.
Hope this helps! Let me know if you have any further questions for us.
Best,
Ai
-From Ai, Community Specialist.