Error
number
Description
What’s going on?
E42
E51
Your Nest may have
tripped an internal fuse
and Nest needs to be
replaced.
Your Nest either has wires that aren't fully inserted into the
connectors or has tripped an internal fuse.
N1
N21
Power wire Rc detected.
Not connected to
equipment.
Your Nest isn’t electrically detecting your Rc wire, but one is
connected to the Nest base.
N2
N22
Power wire Rh detected.
Not connected to
equipment.
Your Nest isn’t electrically detecting your Rh wire, but one is
connected to the Nest base.
N3
N23
No power to W1wire
detected.
Your Nest isn’t electrically detecting your W1wire, but one is
connected to the Nest base.
N4
N24
No power to Y1wire
detected.
Your Nest isn’t electrically detecting your Y1wire, but one is
connected to the Nest base.
N5
N25
No power to AUX/W2 wire
detected.
Your Nest isn’t electrically detecting your AUX/W2 wire, but one is
connected to the Nest base.
N6
N26
No power to G wire
detected.
Your Nest isn’t electrically detecting your G wire, but one is
connected to the Nest base.
N7
N27
No power to O/B wire
detected.
Your Nest isn’t electrically detecting your O/B wire, but one is
connected to the Nest base.
N28
No power to Y2 wire
detected.
Your Nest isn’t electrically detecting your Y2 wire, but one is
connected to the Nest base.
N29
No power to * wire
detected.
Your Nest isn’t electrically detecting your * wire, but one is
connected to the Nest base.
W1
Nest can’t continue to
connect to your Wi-Fi
network.
Your Wi-Fi access point may now fully support a Wi-Fi standard
known as power saving mode.
Nest Learning Thermostat installation & configuration guide
Page 26
