i am trying to install my nest thermostat but can't figure out my wires

[rgaila]

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Original Poster: Vincent Bul 

i am trying to install my nest thermostat but can't figure out my wires 

i have 4 wires 

Red connected to +12V

Blue connected to GND 

Yellow connected to B

White connected to A on the attic the wire is green 

what wire goes where, on my nest thermostat?

It is al conected to a Nibe F1255-6 R PC system

[rgaila]

Hello Vincent, 

We're so sorry for the delay in our response! I can definitely understand the confusion when it comes to wiring issues as it can be very confusing to figure out sometimes, but I'm happy to look into this for you. 

Based on what I gleaned from your wire identification, you have an A and B wire, which would indicate that your HVAC has a proprietary system that makes it incompatible with other thermostats, including Nest. While installing your device, did you receive any errors/warning messages from the Google Home or Nest app? Usually, there is a step-by-step setup which includes a wiring diagram. 

However, since we're unable to inspect it up close,  you can use the Compatibility Checker to see if your system is compatible. Using this article to help identify the different wires is a great point of reference if you look into contacting a pro to come out to help you with this since A/B wires may indicate an incompatibility. Please let me know if you have any more questions or concerns as I'm happy to help.

-From Garrett DS, Community Specialist.