On the covered Google Nest thermostat, E12, E32, E82, E162 means the thermostat detects no power to the W1 (heating) wire. First, check the system power switch and breaker. Then: Google's "Troubleshoot power" steps: confirm power, then turn power off, pull the display, check each wire is fully inserted with its button down and about 3/8 inch (6 mm) exposed, and check the W1 wire is connected properly at the system board.
Differential
Likely causes of “Google Nest thermostat code E12, E32, E82, E162”, and how to tell them apart
- 1
The system power switch is off
What separates it No power to the heating wire
How to confirm Check the switch and breaker
- 2
A tripped breaker or blown fuse
What separates it The furnace is dead
How to confirm Reset the breaker once
- 3
A wire loose at the thermostat
What separates it W1 is not seated
How to confirm Reseat the W1 wire
- 4
A wire loose at the system board
What separates it W1 is not connected there
How to confirm Check the board connection
- 5
A failed transformer or control board
What separates it The system has no low voltage
How to confirm Technician diagnosis
Before you touch a setting
Record this first — changing settings destroys the evidence
- The code shown
- Whether the furnace has power
- The breaker state
Try in this order
0 of 8 completedWhat to do first
ReversibleCheck the system power switch and breaker.
Correct only the documented fault domain
ReversibleGoogle's "Troubleshoot power" steps: confirm power, then turn power off, pull the display, check each wire is fully inserted with its button down and about 3/8 inch (6 mm) exposed, and check the W1 wire is connected properly at the system board.
Confirm the system has power
ReversibleSwitch and breaker.
Turn power off
ReversibleBefore opening anything.
Pull the display
ReversibleCheck each wire.
Check the W1 wire
ReversibleSeated, button down, about 3/8 inch bare.
Check W1 at the system board
ReversibleConnected properly.
Restore power
ReversibleAnd test heating.
Model-specific
What is true of this model and not of its siblings
- Four codes, one problem
- E12, E32, E82 and E162 all report no power to the W1 wire, the heating call wire. The thermostat tried to call for heat and found no supply on that wire.
- Google's troubleshoot power steps
- Confirm power, then turn it off, pull the display, check each wire is fully inserted with its button down and about 3/8 inch exposed, and check the W1 wire at the system board.
- If it is the system
- A dead transformer or a tripped safety switch in the furnace removes the low voltage the thermostat needs, so look at the furnace's status light.
- What a technician tests
- The technician measures the voltage between R and W at the thermostat base, then at the system board, to see where the signal is lost. A reading at one end but not the other points to the wire; no reading at either points to the board or transformer.
- Why four codes
- The thermostat gives different numbers for the same symptom depending on what it was doing when it noticed, such as heating a particular stage. Whichever you see, the check is the W1 wire and the system power.
- Heat pumps and extra wires
- Systems with a heat pump or auxiliary heat may use W2 or an O and B wire as well. If the thermostat was set up for one arrangement and the wiring is another, W1 may be correct on the wall but wrong in the settings. Run the setup again and answer the equipment questions with the label on your equipment beside you.
Stop boundary
When this stops being a self-service repair
- !Google's steps start with confirming power
- !If wiring at the board is involved, call an HVAC technician
Evidence ledger
Sources behind this answer
Exact questions
Common questions
What does E12, E32, E82, E162 mean on a Google Nest thermostat?+
The thermostat detects no power to the W1 (heating) wire.
What do these codes mean?+
The thermostat detects no power to the W1 heating wire.
What is W1?+
The heating call wire.
Where do I start?+
Confirm power at the switch and breaker.
Do I open the furnace?+
Only a technician should.