Mysa
Mysa 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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E01
Thermostat display shows E01 and will not connect to Wi‑Fi or the Mysa app.
Wi‑Fi Radio Initialization Failure
E02
Thermostat shows E02 and will not complete initial setup or pairing with the Mysa app.
Provisioning / Pairing Failure
E03
Thermostat displays E03 and will not turn the heater on or off correctly.
Line Voltage Detection Error
E04
Thermostat shows E04 and the room temperature reading is clearly wrong (e.g., shows 5°C when room is warm).
Internal Temperature Sensor Failure
E05
Thermostat displays E05 and will not control the heater; may show a warning about load or relay.
Load Relay / Triac Failure or Overload
E06
Thermostat shows E06 and becomes unresponsive or reboots when calling for heat.
Internal Overtemperature Protection Trip
E07
Thermostat displays E07 and cannot detect or control the connected heater load.
Load Detection / Zero-Cross Circuit Failure
E08
Thermostat shows E08 and cannot complete firmware update or behaves erratically after an update attempt.
Firmware Update / Memory Write Failure
E09
Thermostat displays E09 and cannot connect to cloud services or voice assistants despite being on Wi‑Fi.
Cloud Service Communication Error
E10
Thermostat shows E10 and the screen is dim, flickering, or randomly turning off.
Display Power / Backlight Driver Fault
E11
Thermostat displays E11 and cannot detect an external floor sensor (for in-floor heating models).
External Floor Sensor Open Circuit
E12
Thermostat shows E12 and reports a floor sensor short or extremely high temperature reading.
External Floor Sensor Short Circuit
E13
Thermostat displays E13 and cannot control a 2-wire in-floor heating system correctly.
Load Type / Compatibility Error
E14
Thermostat shows E14 and the time/schedule will not stay accurate or sync with the app.
Real-Time Clock / Time Sync Error
E15
Thermostat displays E15 and the touch buttons or touch screen do not respond reliably.
Capacitive Touch Interface Failure
E16
Thermostat shows E16 and frequently disconnects from Wi‑Fi, especially when heating turns on.
Power Supply Brownout / Wi‑Fi Drop Under Load
E17
Thermostat displays E17 and cannot join a smart home platform (e.g., HomeKit, Alexa) even though Wi‑Fi works.
Smart Home Integration Handshake Error
E18
Thermostat shows E18 and reports an internal hardware fault; device may reboot repeatedly.
General Hardware Self-Test Failure
Symptom
Heater runs continuously and overheats the room even when the thermostat is set low or turned off.
Stuck Output Triac / Relay Welded Closed
Symptom
Room temperature overshoots setpoint by several degrees before heater turns off.
Poor Temperature Regulation / Overshoot
Symptom
Thermostat backlight or display is very dim and hard to read, but device otherwise works.
Backlight Degradation / Display Aging
Symptom
Thermostat display is on but screen is blank or frozen; no response to touch or buttons.
User Interface Lockup / MCU Hang
Symptom
Thermostat does not follow geofencing or occupancy-based control from the app.
Geolocation / Presence Automation Failure
Symptom
Thermostat does not respond to commands from the Mysa app, but local control works.
Cloud Control / API Communication Issue
Symptom
Thermostat emits a faint electrical smell or shows discoloration around terminals.
Localized Overheating / Terminal Damage
Symptom
Thermostat fails to detect or control an external floor sensor; floor temperature never changes from a default value.
Floor Sensor Input Not Recognized
Symptom
Thermostat frequently disconnects from Wi‑Fi and appears offline in the Mysa app.
Intermittent Wi‑Fi Connectivity
Symptom
Thermostat makes clicking or buzzing noises when turning the heater on or off.
Noisy Relay / Electrical Buzz
Symptom
Thermostat or wall plate feels unusually hot to the touch during normal operation.
Excessive Internal Heating / Overload
Symptom
Thermostat powers on but does not heat the room; heater never turns on even when setpoint is higher than room temperature.
Output Stage Not Switching Load
Symptom
Thermostat randomly resets or reboots, especially when the heater turns on.
Power Supply Instability / Brownout
Symptom
Thermostat schedules do not run as programmed; heating turns on/off at wrong times.
Scheduling / Timekeeping Fault
Symptom
Thermostat shows significantly incorrect room temperature (e.g., always 3–5°C off) but no error code is displayed.
Temperature Calibration Drift
Symptom
Thermostat will not power on at all (no display, no lights) after installation.
No Line Voltage / Internal Power Supply Failure
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E01 |
Thermostat display shows E01 and will not connect to Wi‑Fi or the Mysa app.
|
Wi‑Fi Radio Initialization Failure | View Details |
| E02 |
Thermostat shows E02 and will not complete initial setup or pairing with the Mysa app.
|
Provisioning / Pairing Failure | View Details |
| E03 |
Thermostat displays E03 and will not turn the heater on or off correctly.
|
Line Voltage Detection Error | View Details |
| E04 |
Thermostat shows E04 and the room temperature reading is clearly wrong (e.g., shows 5°C when room is warm).
|
Internal Temperature Sensor Failure | View Details |
| E05 |
Thermostat displays E05 and will not control the heater; may show a warning about load or relay.
|
Load Relay / Triac Failure or Overload | View Details |
| E06 |
Thermostat shows E06 and becomes unresponsive or reboots when calling for heat.
|
Internal Overtemperature Protection Trip | View Details |
| E07 |
Thermostat displays E07 and cannot detect or control the connected heater load.
|
Load Detection / Zero-Cross Circuit Failure | View Details |
| E08 |
Thermostat shows E08 and cannot complete firmware update or behaves erratically after an update attempt.
|
Firmware Update / Memory Write Failure | View Details |
| E09 |
Thermostat displays E09 and cannot connect to cloud services or voice assistants despite being on Wi‑Fi.
|
Cloud Service Communication Error | View Details |
| E10 |
Thermostat shows E10 and the screen is dim, flickering, or randomly turning off.
|
Display Power / Backlight Driver Fault | View Details |
| E11 |
Thermostat displays E11 and cannot detect an external floor sensor (for in-floor heating models).
|
External Floor Sensor Open Circuit | View Details |
| E12 |
Thermostat shows E12 and reports a floor sensor short or extremely high temperature reading.
|
External Floor Sensor Short Circuit | View Details |
| E13 |
Thermostat displays E13 and cannot control a 2-wire in-floor heating system correctly.
|
Load Type / Compatibility Error | View Details |
| E14 |
Thermostat shows E14 and the time/schedule will not stay accurate or sync with the app.
|
Real-Time Clock / Time Sync Error | View Details |
| E15 |
Thermostat displays E15 and the touch buttons or touch screen do not respond reliably.
|
Capacitive Touch Interface Failure | View Details |
| E16 |
Thermostat shows E16 and frequently disconnects from Wi‑Fi, especially when heating turns on.
|
Power Supply Brownout / Wi‑Fi Drop Under Load | View Details |
| E17 |
Thermostat displays E17 and cannot join a smart home platform (e.g., HomeKit, Alexa) even though Wi‑Fi works.
|
Smart Home Integration Handshake Error | View Details |
| E18 |
Thermostat shows E18 and reports an internal hardware fault; device may reboot repeatedly.
|
General Hardware Self-Test Failure | View Details |
| – |
Heater runs continuously and overheats the room even when the thermostat is set low or turned off.
|
Stuck Output Triac / Relay Welded Closed | View Details |
| – |
Room temperature overshoots setpoint by several degrees before heater turns off.
|
Poor Temperature Regulation / Overshoot | View Details |
| – |
Thermostat backlight or display is very dim and hard to read, but device otherwise works.
|
Backlight Degradation / Display Aging | View Details |
| – |
Thermostat display is on but screen is blank or frozen; no response to touch or buttons.
|
User Interface Lockup / MCU Hang | View Details |
| – |
Thermostat does not follow geofencing or occupancy-based control from the app.
|
Geolocation / Presence Automation Failure | View Details |
| – |
Thermostat does not respond to commands from the Mysa app, but local control works.
|
Cloud Control / API Communication Issue | View Details |
| – |
Thermostat emits a faint electrical smell or shows discoloration around terminals.
|
Localized Overheating / Terminal Damage | View Details |
| – |
Thermostat fails to detect or control an external floor sensor; floor temperature never changes from a default value.
|
Floor Sensor Input Not Recognized | View Details |
| – |
Thermostat frequently disconnects from Wi‑Fi and appears offline in the Mysa app.
|
Intermittent Wi‑Fi Connectivity | View Details |
| – |
Thermostat makes clicking or buzzing noises when turning the heater on or off.
|
Noisy Relay / Electrical Buzz | View Details |
| – |
Thermostat or wall plate feels unusually hot to the touch during normal operation.
|
Excessive Internal Heating / Overload | View Details |
| – |
Thermostat powers on but does not heat the room; heater never turns on even when setpoint is higher than room temperature.
|
Output Stage Not Switching Load | View Details |
| – |
Thermostat randomly resets or reboots, especially when the heater turns on.
|
Power Supply Instability / Brownout | View Details |
| – |
Thermostat schedules do not run as programmed; heating turns on/off at wrong times.
|
Scheduling / Timekeeping Fault | View Details |
| – |
Thermostat shows significantly incorrect room temperature (e.g., always 3–5°C off) but no error code is displayed.
|
Temperature Calibration Drift | View Details |
| – |
Thermostat will not power on at all (no display, no lights) after installation.
|
No Line Voltage / Internal Power Supply Failure | View Details |
No matching codes found
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