Eurotronic
Eurotronic 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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CF
Thermostat shows 'CF' or 'CAL' and does not control heating until calibration completes or fails.
Calibration Mode / Calibration Failure
E1
Thermostat display shows E1 and heating does not start even when room temperature is below setpoint.
Room Temperature Sensor Fault
E2
Thermostat shows E2 and radiator valve does not regulate temperature correctly.
External / Floor / Remote Sensor Fault
E3
Thermostat displays E3 and the device becomes unresponsive or reboots frequently.
Internal Temperature Sensor Fault / Overtemperature Detection
E4
Thermostat shows E4 and cannot control the heating valve or boiler relay.
Output Relay / Valve Drive Fault
E5
Thermostat displays E5 and cannot complete calibration of the motorized radiator valve (Eurotronic smart TRV).
Valve Stroke Calibration Error
E6
Thermostat shows E6 and cannot communicate with the motorized valve or remote module.
Actuator Communication Error
E7
Thermostat displays E7 and cannot connect to the home gateway or app (Eurotronic smart thermostat with gateway).
Gateway / Cloud Communication Fault
E8
Thermostat shows E8 and frequently restarts or freezes.
Power Supply / Voltage Fault
E9
Thermostat displays E9 and cannot complete firmware update or behaves erratically after update attempt.
Firmware / Memory Corruption
Er1
Display shows 'Er1' and thermostat cannot read internal sensor values.
Internal Sensor Communication Error
Er2
Display shows 'Er2' and thermostat cannot drive the motorized valve correctly.
Motor Drive Error
Er3
Display shows 'Er3' and thermostat cannot store new schedules or settings.
Non-Volatile Memory Error
Er4
Display shows 'Er4' and thermostat time/date resets frequently.
Real-Time Clock / Backup Power Fault
Er5
Display shows 'Er5' and thermostat cannot detect or control external relay module.
Bus Communication Error with External Module
Err
Display shows 'Err' without a numeric code and thermostat does not respond to inputs.
General System Error
Hi
Display shows 'Hi' and thermostat stops heating control or shows unrealistic high temperature.
Overtemperature or Sensor Overrange
Lo
Display shows 'Lo' or battery icon flashes and thermostat or TRV becomes unresponsive.
Low Battery Condition
noC
Display shows 'noC' or 'no Conn' and thermostat cannot be controlled from the app or gateway.
No Connection to Central Controller
rF
Display shows 'rF' or radio symbol with error and thermostat cannot reach remote sensors or TRVs.
Radio Frequency Communication Fault
Symptom
Eurotronic smart TRV does not close fully; radiator remains warm even when set to low temperature.
TRV Not Closing / Constant Flow
Symptom
Radiator or floor heating stays hot even when thermostat is set to OFF or a low temperature.
Heating Stuck On
Symptom
Radiator with Eurotronic smart TRV does not heat up at all, while other radiators work normally.
Single Radiator Not Heating
Symptom
Room stays cold even though thermostat is calling for heat; boiler or valve does not activate.
No Heat Output Despite Heat Demand
Symptom
Smart thermostat cannot be discovered or added in the Eurotronic app during setup.
Pairing / Commissioning Failure
Symptom
Thermostat backlight or display flickers or is very dim, but device otherwise works.
Display / Backlight Fault
Symptom
Thermostat display is completely blank and device does not respond.
No Power / Dead Display
Symptom
Thermostat display is on but buttons or rotary knob do not respond or respond intermittently.
Unresponsive User Interface
Symptom
Thermostat does not follow programmed schedule; heating turns on/off at wrong times.
Scheduling / Timer Malfunction
Symptom
Thermostat emits a burning smell or visible smoke.
Severe Electrical Failure / Overheating
Symptom
Thermostat frequently drops connection to the app or gateway, then reconnects later.
Intermittent Network Connection
Symptom
Thermostat frequently loses time schedules or reverts to default settings after power interruptions.
Settings Not Saved / Memory Loss
Symptom
Thermostat or TRV becomes very warm to the touch during normal operation.
Overheating of Device Housing
Symptom
Thermostat or TRV frequently shows child lock or locked symbol and cannot be adjusted locally.
Child Lock / Local Lockout Issues
Symptom
Thermostat or TRV makes loud clicking, buzzing, or grinding noises during operation.
Abnormal Mechanical Noise
Symptom
Thermostat or TRV plastic housing is cracked or broken, exposing internal components.
Mechanical Housing Damage
Symptom
Thermostat or TRV shows condensation inside the display or housing, and operation is erratic.
Moisture Ingress / Condensation
Symptom
Thermostat shows a temperature that is clearly wrong (e.g., 5°C or 35°C in a normal room).
Incorrect Temperature Reading
Symptom
Thermostat shows large temperature swings; room is alternately too hot and too cold.
Poor Temperature Regulation / Overshoot
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| CF |
Thermostat shows 'CF' or 'CAL' and does not control heating until calibration completes or fails.
|
Calibration Mode / Calibration Failure | View Details |
| E1 |
Thermostat display shows E1 and heating does not start even when room temperature is below setpoint.
|
Room Temperature Sensor Fault | View Details |
| E2 |
Thermostat shows E2 and radiator valve does not regulate temperature correctly.
|
External / Floor / Remote Sensor Fault | View Details |
| E3 |
Thermostat displays E3 and the device becomes unresponsive or reboots frequently.
|
Internal Temperature Sensor Fault / Overtemperature Detection | View Details |
| E4 |
Thermostat shows E4 and cannot control the heating valve or boiler relay.
|
Output Relay / Valve Drive Fault | View Details |
| E5 |
Thermostat displays E5 and cannot complete calibration of the motorized radiator valve (Eurotronic smart TRV).
|
Valve Stroke Calibration Error | View Details |
| E6 |
Thermostat shows E6 and cannot communicate with the motorized valve or remote module.
|
Actuator Communication Error | View Details |
| E7 |
Thermostat displays E7 and cannot connect to the home gateway or app (Eurotronic smart thermostat with gateway).
|
Gateway / Cloud Communication Fault | View Details |
| E8 |
Thermostat shows E8 and frequently restarts or freezes.
|
Power Supply / Voltage Fault | View Details |
| E9 |
Thermostat displays E9 and cannot complete firmware update or behaves erratically after update attempt.
|
Firmware / Memory Corruption | View Details |
| Er1 |
Display shows 'Er1' and thermostat cannot read internal sensor values.
|
Internal Sensor Communication Error | View Details |
| Er2 |
Display shows 'Er2' and thermostat cannot drive the motorized valve correctly.
|
Motor Drive Error | View Details |
| Er3 |
Display shows 'Er3' and thermostat cannot store new schedules or settings.
|
Non-Volatile Memory Error | View Details |
| Er4 |
Display shows 'Er4' and thermostat time/date resets frequently.
|
Real-Time Clock / Backup Power Fault | View Details |
| Er5 |
Display shows 'Er5' and thermostat cannot detect or control external relay module.
|
Bus Communication Error with External Module | View Details |
| Err |
Display shows 'Err' without a numeric code and thermostat does not respond to inputs.
|
General System Error | View Details |
| Hi |
Display shows 'Hi' and thermostat stops heating control or shows unrealistic high temperature.
|
Overtemperature or Sensor Overrange | View Details |
| Lo |
Display shows 'Lo' or battery icon flashes and thermostat or TRV becomes unresponsive.
|
Low Battery Condition | View Details |
| noC |
Display shows 'noC' or 'no Conn' and thermostat cannot be controlled from the app or gateway.
|
No Connection to Central Controller | View Details |
| rF |
Display shows 'rF' or radio symbol with error and thermostat cannot reach remote sensors or TRVs.
|
Radio Frequency Communication Fault | View Details |
| – |
Eurotronic smart TRV does not close fully; radiator remains warm even when set to low temperature.
|
TRV Not Closing / Constant Flow | View Details |
| – |
Radiator or floor heating stays hot even when thermostat is set to OFF or a low temperature.
|
Heating Stuck On | View Details |
| – |
Radiator with Eurotronic smart TRV does not heat up at all, while other radiators work normally.
|
Single Radiator Not Heating | View Details |
| – |
Room stays cold even though thermostat is calling for heat; boiler or valve does not activate.
|
No Heat Output Despite Heat Demand | View Details |
| – |
Smart thermostat cannot be discovered or added in the Eurotronic app during setup.
|
Pairing / Commissioning Failure | View Details |
| – |
Thermostat backlight or display flickers or is very dim, but device otherwise works.
|
Display / Backlight Fault | View Details |
| – |
Thermostat display is completely blank and device does not respond.
|
No Power / Dead Display | View Details |
| – |
Thermostat display is on but buttons or rotary knob do not respond or respond intermittently.
|
Unresponsive User Interface | View Details |
| – |
Thermostat does not follow programmed schedule; heating turns on/off at wrong times.
|
Scheduling / Timer Malfunction | View Details |
| – |
Thermostat emits a burning smell or visible smoke.
|
Severe Electrical Failure / Overheating | View Details |
| – |
Thermostat frequently drops connection to the app or gateway, then reconnects later.
|
Intermittent Network Connection | View Details |
| – |
Thermostat frequently loses time schedules or reverts to default settings after power interruptions.
|
Settings Not Saved / Memory Loss | View Details |
| – |
Thermostat or TRV becomes very warm to the touch during normal operation.
|
Overheating of Device Housing | View Details |
| – |
Thermostat or TRV frequently shows child lock or locked symbol and cannot be adjusted locally.
|
Child Lock / Local Lockout Issues | View Details |
| – |
Thermostat or TRV makes loud clicking, buzzing, or grinding noises during operation.
|
Abnormal Mechanical Noise | View Details |
| – |
Thermostat or TRV plastic housing is cracked or broken, exposing internal components.
|
Mechanical Housing Damage | View Details |
| – |
Thermostat or TRV shows condensation inside the display or housing, and operation is erratic.
|
Moisture Ingress / Condensation | View Details |
| – |
Thermostat shows a temperature that is clearly wrong (e.g., 5°C or 35°C in a normal room).
|
Incorrect Temperature Reading | View Details |
| – |
Thermostat shows large temperature swings; room is alternately too hot and too cold.
|
Poor Temperature Regulation / Overshoot | View Details |
No matching codes found
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