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Wiring Help Please - Honeywell Wire says "L/A or A", where to attach to Nest Thermostat?

DanInFlorida7
Community Member

Need Thermostat wiring advice. Trying to hook up Nest Learning Thermostat. QUESTION: The bottom wire "A or L/A" on the Honeywell TH8320R1003 thermostat, SHOULD IT BE CONNECTED TO THE "W2 AUX" ON THE NEST?  The Honeywell site describes  it as:  "L/A – A – Input for heat pump fault".  Photo Attached of Honeywell Wiring.

Thanks for any advice.  DanTH8320R1003 thermostatTH8320R1003 thermostat

1 REPLY 1

CoolingWizard
Platinum Product Expert
Platinum Product Expert

@DanInFlorida7 , The L wire is designed for turning on the auxiliary or Emergency heat light on the thermostat. Anytime the heat pump activates the auxiliary heat that light will be turned on by that white wire. The nest thermostat does not need that wire so you can simply wrap it around the brown thermostat insulation and tuck it in the wall.  
Because you happen to have a tan L wire this leads me to believe that what you actually have is a heat pump and your white wire is actually your OB wire. You do not appear to have auxiliary heat in your system, though. 

AC Cooling Wizard

NestPro, Google Pro, Mechanical Engineer and HVAC service company owner.