Heat Pump Wiring

[Ken_P25]

Hello.  I recently moved into a condo with GE Zoneline PTAC with heat pump units (model AZ65H07DAD) installed that are connected to Nest Learning Thermostats (Gen 3).  The wiring inside the PTAC units includes wires connected to terminals R, GL, GH, B, Y, W, and C.  I am unsure whether the original condo owner had the correct wire connections to the thermostat because Nest was reading a dual fuel system.  There is only a single fuel source - electricity.  What is the correct thermostat wiring for my configuration?

[zoeuvre]

Hi Ken_P25, 

Thanks for posting here in the Community forum and for showing interest in our Nest Thermostats. I highly recommend you contact a local HVAC professional for assistance since your PTAC units include wires connected to terminals GL and GH, which are terminals for the heating and cooling system's fans with multiple speeds. A GL and GH wire may control either the second or third speed of your system’s fan. Your pro can tell which speed this wire controls. Learn more about multi-speed fans here.

Let us know if that helps.

Best,

Zoe