Emerson
Emerson Smart Thermostats Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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E1
Thermostat displays E1 and will not control heating or cooling
Indoor Temperature Sensor Open Circuit
E10
Thermostat displays E10 and system does not respond to temperature changes
Relay Output Failure / Load Control Fault
E11
Thermostat displays E11 and indicates high internal temperature or shuts down display
Thermostat Overtemperature Protection
E12
Thermostat displays E12 and may show incorrect date/time or lose schedules
Real-Time Clock / Backup Power Fault
E13
Thermostat displays E13 and indicates sensor calibration error
Temperature Calibration Out of Range
E2
Thermostat displays E2 and shows incorrect or no room temperature reading
Indoor Temperature Sensor Short Circuit
E20
Thermostat displays E20 and indicates C-wire or power adapter problem
Common Wire / Power Adapter Detection Fault
E21
Thermostat displays E21 and indicates fan control fault
G Terminal / Fan Relay Control Error
E22
Thermostat displays E22 and indicates heat call output fault
W/W1 Heating Output Error
E23
Thermostat displays E23 and indicates cooling output fault
Y/Y1 Cooling Output Error
E24
Thermostat displays E24 and indicates heat pump reversing valve fault
O/B Reversing Valve Control Error
E3
Thermostat displays E3 and may not control the system correctly
Outdoor Temperature Sensor Fault (if equipped)
E4
Thermostat displays E4 and may shut down heating or cooling
Internal Humidity Sensor Fault (models with humidity control)
E5
Thermostat displays E5 and system will not run or runs erratically
Power Supply / Low-Voltage Input Fault
E6
Thermostat displays E6 and cannot communicate with HVAC equipment interface or Wi‑Fi module
Communication Bus Error
E7
Thermostat displays E7 and may lock out heating or cooling
System Configuration / Equipment Type Mismatch
E8
Thermostat displays E8 and will not connect to Wi‑Fi or Emerson cloud services
Wi‑Fi Module / Network Communication Fault
E9
Thermostat displays E9 and may reboot or freeze intermittently
Internal Memory / Firmware Error
Symptom
Indoor fan runs continuously even when thermostat is set to Auto
Continuous Fan Operation
Symptom
Thermostat backlight or touchscreen does not respond to touch
Touchscreen / User Interface Failure
Symptom
Thermostat calls for heat but furnace short cycles or shuts off quickly
Short Cycling Due to Control or Sensor Issues
Symptom
Thermostat cycles equipment rapidly on and off (short run times) in cooling mode
Cooling Short Cycling Due to Control Settings
Symptom
Thermostat display is completely blank and system does not run
No Power to Thermostat
Symptom
Thermostat does not detect or control whole-home humidifier/dehumidifier
Accessory Control / HUM/DEHUM Output Issue
Symptom
Thermostat does not follow programmed schedule or changes temperature on its own
Scheduling / Smart Feature Misconfiguration
Symptom
Thermostat does not power up after installation on new system
Incorrect Initial Wiring / No Common
Symptom
Thermostat emits a burning smell or feels unusually hot to the touch
Overheating or Electrical Component Failure
Symptom
Thermostat frequently disconnects from Wi‑Fi or Emerson app
Intermittent Wi‑Fi Connectivity
Symptom
Thermostat frequently displays "Waiting" or delay before starting equipment
Compressor/Equipment Short-Cycle Protection Delay
Symptom
Thermostat is on but does not call for cooling when room is warm
No Cooling Call from Thermostat
Symptom
Thermostat is on but does not call for heat when room is cold
No Heat Call from Thermostat
Symptom
Thermostat loses date/time and Wi‑Fi settings after every power outage
Loss of Non-Volatile Settings
Symptom
Thermostat reboots randomly or freezes and becomes unresponsive
Intermittent Thermostat Power or Firmware Lockup
Symptom
Thermostat shows "Aux Heat" or emergency heat running too often on a heat pump system
Excessive Auxiliary Heat Usage
Symptom
Thermostat shows "Heat On" or "Cool On" but equipment does not start
Thermostat Calling but Equipment Not Responding
Symptom
Thermostat shows room temperature that is clearly too high or too low
Inaccurate Room Temperature Sensing
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E1 |
Thermostat displays E1 and will not control heating or cooling
|
Indoor Temperature Sensor Open Circuit | View Details |
| E10 |
Thermostat displays E10 and system does not respond to temperature changes
|
Relay Output Failure / Load Control Fault | View Details |
| E11 |
Thermostat displays E11 and indicates high internal temperature or shuts down display
|
Thermostat Overtemperature Protection | View Details |
| E12 |
Thermostat displays E12 and may show incorrect date/time or lose schedules
|
Real-Time Clock / Backup Power Fault | View Details |
| E13 |
Thermostat displays E13 and indicates sensor calibration error
|
Temperature Calibration Out of Range | View Details |
| E2 |
Thermostat displays E2 and shows incorrect or no room temperature reading
|
Indoor Temperature Sensor Short Circuit | View Details |
| E20 |
Thermostat displays E20 and indicates C-wire or power adapter problem
|
Common Wire / Power Adapter Detection Fault | View Details |
| E21 |
Thermostat displays E21 and indicates fan control fault
|
G Terminal / Fan Relay Control Error | View Details |
| E22 |
Thermostat displays E22 and indicates heat call output fault
|
W/W1 Heating Output Error | View Details |
| E23 |
Thermostat displays E23 and indicates cooling output fault
|
Y/Y1 Cooling Output Error | View Details |
| E24 |
Thermostat displays E24 and indicates heat pump reversing valve fault
|
O/B Reversing Valve Control Error | View Details |
| E3 |
Thermostat displays E3 and may not control the system correctly
|
Outdoor Temperature Sensor Fault (if equipped) | View Details |
| E4 |
Thermostat displays E4 and may shut down heating or cooling
|
Internal Humidity Sensor Fault (models with humidity control) | View Details |
| E5 |
Thermostat displays E5 and system will not run or runs erratically
|
Power Supply / Low-Voltage Input Fault | View Details |
| E6 |
Thermostat displays E6 and cannot communicate with HVAC equipment interface or Wi‑Fi module
|
Communication Bus Error | View Details |
| E7 |
Thermostat displays E7 and may lock out heating or cooling
|
System Configuration / Equipment Type Mismatch | View Details |
| E8 |
Thermostat displays E8 and will not connect to Wi‑Fi or Emerson cloud services
|
Wi‑Fi Module / Network Communication Fault | View Details |
| E9 |
Thermostat displays E9 and may reboot or freeze intermittently
|
Internal Memory / Firmware Error | View Details |
| – |
Indoor fan runs continuously even when thermostat is set to Auto
|
Continuous Fan Operation | View Details |
| – |
Thermostat backlight or touchscreen does not respond to touch
|
Touchscreen / User Interface Failure | View Details |
| – |
Thermostat calls for heat but furnace short cycles or shuts off quickly
|
Short Cycling Due to Control or Sensor Issues | View Details |
| – |
Thermostat cycles equipment rapidly on and off (short run times) in cooling mode
|
Cooling Short Cycling Due to Control Settings | View Details |
| – |
Thermostat display is completely blank and system does not run
|
No Power to Thermostat | View Details |
| – |
Thermostat does not detect or control whole-home humidifier/dehumidifier
|
Accessory Control / HUM/DEHUM Output Issue | View Details |
| – |
Thermostat does not follow programmed schedule or changes temperature on its own
|
Scheduling / Smart Feature Misconfiguration | View Details |
| – |
Thermostat does not power up after installation on new system
|
Incorrect Initial Wiring / No Common | View Details |
| – |
Thermostat emits a burning smell or feels unusually hot to the touch
|
Overheating or Electrical Component Failure | View Details |
| – |
Thermostat frequently disconnects from Wi‑Fi or Emerson app
|
Intermittent Wi‑Fi Connectivity | View Details |
| – |
Thermostat frequently displays "Waiting" or delay before starting equipment
|
Compressor/Equipment Short-Cycle Protection Delay | View Details |
| – |
Thermostat is on but does not call for cooling when room is warm
|
No Cooling Call from Thermostat | View Details |
| – |
Thermostat is on but does not call for heat when room is cold
|
No Heat Call from Thermostat | View Details |
| – |
Thermostat loses date/time and Wi‑Fi settings after every power outage
|
Loss of Non-Volatile Settings | View Details |
| – |
Thermostat reboots randomly or freezes and becomes unresponsive
|
Intermittent Thermostat Power or Firmware Lockup | View Details |
| – |
Thermostat shows "Aux Heat" or emergency heat running too often on a heat pump system
|
Excessive Auxiliary Heat Usage | View Details |
| – |
Thermostat shows "Heat On" or "Cool On" but equipment does not start
|
Thermostat Calling but Equipment Not Responding | View Details |
| – |
Thermostat shows room temperature that is clearly too high or too low
|
Inaccurate Room Temperature Sensing | View Details |
No matching codes found
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