User Guide

My old thermostat has two labels for each
connector
Affected products: 3rd gen Nest Learning Thermostat, 2nd gen Nest Learning Thermostat, 1st
gen Nest Learning Thermostat
Some thermostat wire connectors have two sets of labels: one for conventional systems, one for
systems with a heat pump. You’ll need to know which set of labels to use when you enter your
thermostat’s wires into the Compatibility Checker. Here’s how to tell.
Many thermostats work with both conventional systems (like furnaces, boilers, and AC) and heat
pump systems (condenser units that both heat and cool). These two systems use a slightly
different set of wires, so to accommodate both systems some thermostats have two rows of wire
label or have two labels listed side by side.