Heatit
Heatit 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
Display shows CF and thermostat cannot save settings
Configuration Memory Error
Con
Display shows "Con" and thermostat indicates connection mode
Network Inclusion / Connection Mode Active
E1
Display shows E1 and thermostat stops heating the floor or room
Floor Sensor Open Circuit
E2
Display shows E2 and thermostat stops heating or switches to backup control mode
Floor Sensor Short Circuit
E3
Display shows E3 and thermostat cannot regulate temperature correctly
Internal Room Sensor Fault
E4
Display shows E4 and thermostat stops heating, often after long operation at high load
Internal Overheat Protection Triggered
E5
Display shows E5 and thermostat does not respond to temperature changes
Calibration or Sensor Range Error
E6
Display shows E6 and thermostat cannot control external sensor
External Sensor Fault (e.g. Room or Limit Sensor)
E7
Display shows E7 and thermostat refuses to switch heating on
Load Output Overcurrent or Short Circuit
E8
Display shows E8 and thermostat intermittently reboots or freezes
Low Supply Voltage or Power Quality Error
E9
Display shows E9 and thermostat cannot complete startup
Internal Firmware or Memory Error
Er1
Display shows Er1 and thermostat cannot read floor temperature
Floor Sensor Not Detected or Wrong Type
Er2
Display shows Er2 and thermostat shows unrealistic floor temperatures
Floor Sensor Out of Range
Er3
Display shows Er3 and thermostat cannot read internal temperature
Internal Room Sensor Out of Range
Er4
Display shows Er4 and thermostat output is locked off
Overtemperature Limit Sensor Triggered
Er5
Display shows Er5 and thermostat cannot control external room sensor
External Room Sensor Out of Range
Er6
Display shows Er6 and thermostat cannot switch heating on even though demand is present
Internal Relay/Triac Failure
Er7
Display shows Er7 and thermostat cannot communicate with external module or gateway
Communication Module Error
Hi
Display shows "Hi" instead of temperature and thermostat locks out heating
Measured Temperature Above Sensor Range
Lo
Display shows "Lo" instead of temperature and heating does not start
Measured Temperature Below Sensor Range
LOC
Display shows LOC and buttons do not respond
Keypad Lock / Child Lock Activated
noP
Display shows "noP" and thermostat does not detect any load
No Load Detected on Output
Symptom
Floor is hot in some areas and cold in others despite thermostat calling for heat
Uneven Floor Heating
Symptom
Room temperature overshoots setpoint by several degrees before heating turns off
Poor Temperature Regulation / Overshoot
Symptom
Thermostat cannot be added to Z-Wave or Zigbee network
Pairing / Inclusion Failure
Symptom
Thermostat display is completely dead, no lights or response
No Power to Thermostat
Symptom
Thermostat display is on but buttons do not respond (no LOC code shown)
Keypad Failure or Front Panel Fault
Symptom
Thermostat display is very dim or backlight flickers
Display Backlight or Power Regulation Issue
Symptom
Thermostat frequently cycles on and off, causing relay clicking and uneven temperature
Short Cycling / Incorrect Hysteresis
Symptom
Thermostat frequently drops connection from smart home gateway
Unstable Wireless Communication
Symptom
Thermostat heats continuously and does not turn off even when setpoint is reached
Stuck Relay/Triac or Sensor Misreading
Symptom
Thermostat loses time, schedules, or settings after power outage
Non-Volatile Memory or Backup Power Issue
Symptom
Thermostat makes audible clicking or buzzing noises during operation
Relay Operation Noise or Electrical Buzz
Symptom
Thermostat or wall box feels unusually warm to the touch during operation
Overheating of Thermostat Housing
Symptom
Thermostat plastic housing is discolored or slightly melted near terminals
Thermal Damage from Overheating Terminals
Symptom
Thermostat powers on but does not heat even when setpoint is higher than room temperature
No Heat Output / Output Stage Not Switching
Symptom
Thermostat randomly resets or reboots during operation
Intermittent Power or Internal Fault
Symptom
Thermostat schedules do not follow programmed times
Scheduling / Timer Misconfiguration
Symptom
Thermostat shows correct temperature but floor feels cold
Underheating / Insufficient Output
Symptom
Thermostat shows much higher room temperature than actual
Room Sensor Overreading
Symptom
Thermostat shows much lower room temperature than actual
Room Sensor Underreading
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| CF |
Display shows CF and thermostat cannot save settings
|
Configuration Memory Error | View Details |
| Con |
Display shows "Con" and thermostat indicates connection mode
|
Network Inclusion / Connection Mode Active | View Details |
| E1 |
Display shows E1 and thermostat stops heating the floor or room
|
Floor Sensor Open Circuit | View Details |
| E2 |
Display shows E2 and thermostat stops heating or switches to backup control mode
|
Floor Sensor Short Circuit | View Details |
| E3 |
Display shows E3 and thermostat cannot regulate temperature correctly
|
Internal Room Sensor Fault | View Details |
| E4 |
Display shows E4 and thermostat stops heating, often after long operation at high load
|
Internal Overheat Protection Triggered | View Details |
| E5 |
Display shows E5 and thermostat does not respond to temperature changes
|
Calibration or Sensor Range Error | View Details |
| E6 |
Display shows E6 and thermostat cannot control external sensor
|
External Sensor Fault (e.g. Room or Limit Sensor) | View Details |
| E7 |
Display shows E7 and thermostat refuses to switch heating on
|
Load Output Overcurrent or Short Circuit | View Details |
| E8 |
Display shows E8 and thermostat intermittently reboots or freezes
|
Low Supply Voltage or Power Quality Error | View Details |
| E9 |
Display shows E9 and thermostat cannot complete startup
|
Internal Firmware or Memory Error | View Details |
| Er1 |
Display shows Er1 and thermostat cannot read floor temperature
|
Floor Sensor Not Detected or Wrong Type | View Details |
| Er2 |
Display shows Er2 and thermostat shows unrealistic floor temperatures
|
Floor Sensor Out of Range | View Details |
| Er3 |
Display shows Er3 and thermostat cannot read internal temperature
|
Internal Room Sensor Out of Range | View Details |
| Er4 |
Display shows Er4 and thermostat output is locked off
|
Overtemperature Limit Sensor Triggered | View Details |
| Er5 |
Display shows Er5 and thermostat cannot control external room sensor
|
External Room Sensor Out of Range | View Details |
| Er6 |
Display shows Er6 and thermostat cannot switch heating on even though demand is present
|
Internal Relay/Triac Failure | View Details |
| Er7 |
Display shows Er7 and thermostat cannot communicate with external module or gateway
|
Communication Module Error | View Details |
| Hi |
Display shows "Hi" instead of temperature and thermostat locks out heating
|
Measured Temperature Above Sensor Range | View Details |
| Lo |
Display shows "Lo" instead of temperature and heating does not start
|
Measured Temperature Below Sensor Range | View Details |
| LOC |
Display shows LOC and buttons do not respond
|
Keypad Lock / Child Lock Activated | View Details |
| noP |
Display shows "noP" and thermostat does not detect any load
|
No Load Detected on Output | View Details |
| – |
Floor is hot in some areas and cold in others despite thermostat calling for heat
|
Uneven Floor Heating | View Details |
| – |
Room temperature overshoots setpoint by several degrees before heating turns off
|
Poor Temperature Regulation / Overshoot | View Details |
| – |
Thermostat cannot be added to Z-Wave or Zigbee network
|
Pairing / Inclusion Failure | View Details |
| – |
Thermostat display is completely dead, no lights or response
|
No Power to Thermostat | View Details |
| – |
Thermostat display is on but buttons do not respond (no LOC code shown)
|
Keypad Failure or Front Panel Fault | View Details |
| – |
Thermostat display is very dim or backlight flickers
|
Display Backlight or Power Regulation Issue | View Details |
| – |
Thermostat frequently cycles on and off, causing relay clicking and uneven temperature
|
Short Cycling / Incorrect Hysteresis | View Details |
| – |
Thermostat frequently drops connection from smart home gateway
|
Unstable Wireless Communication | View Details |
| – |
Thermostat heats continuously and does not turn off even when setpoint is reached
|
Stuck Relay/Triac or Sensor Misreading | View Details |
| – |
Thermostat loses time, schedules, or settings after power outage
|
Non-Volatile Memory or Backup Power Issue | View Details |
| – |
Thermostat makes audible clicking or buzzing noises during operation
|
Relay Operation Noise or Electrical Buzz | View Details |
| – |
Thermostat or wall box feels unusually warm to the touch during operation
|
Overheating of Thermostat Housing | View Details |
| – |
Thermostat plastic housing is discolored or slightly melted near terminals
|
Thermal Damage from Overheating Terminals | View Details |
| – |
Thermostat powers on but does not heat even when setpoint is higher than room temperature
|
No Heat Output / Output Stage Not Switching | View Details |
| – |
Thermostat randomly resets or reboots during operation
|
Intermittent Power or Internal Fault | View Details |
| – |
Thermostat schedules do not follow programmed times
|
Scheduling / Timer Misconfiguration | View Details |
| – |
Thermostat shows correct temperature but floor feels cold
|
Underheating / Insufficient Output | View Details |
| – |
Thermostat shows much higher room temperature than actual
|
Room Sensor Overreading | View Details |
| – |
Thermostat shows much lower room temperature than actual
|
Room Sensor Underreading | View Details |
No matching codes found
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