Baxi 600 Combi

Welcome to the fault-codes section of this site. The following table or page contains the information required to help repair and diagnose the fault codes being shown on the boiler display. You may be guided through the fault finding sequence or steps, for rectifying your boiler with this fault code. Suggested repair solutions may be provided by a link to a repair page. NB Some fault codes are only applicable to a specific range of boilers only.


Error code Possible faultInstaller action
E09Gas valve connection cableCheck the cable PCB/gas valve and gas valve plug.
E10External probe faultCheck the sensor.
E12Differential water flow switch fault (still open)Check the water flow switch.
E13Differential water flow switch fault (still closed)Check the water flow switch.
E15Gas valve command faultCheck the cable PCB/gas valve, replace PCB if necessary.
E20Central heating NTC faultCheck the sensor.
E28Flue NTC faultCheck the sensor.
E40Central heating return NTC faultCheck the sensor.
E50DHW NTC sensor fault (tank boiler) (s.c.) OR DHW NTC sensor fault (tank boiler) (o.c.)Check the sensor.
E83/E84/E85/E86/E87No communicationCheck cable between room unit and PCB or RF link.
E109Pre-circulation faultCheck the correct circulation of the water and the pump.
E118Primary system water pressure too low (< 0.5 bar)Check the water pressure.
E125Circulation fault (primary)Check the correct circulation of the water and the pump
E128Frequent flame failure (12 times)Check the sensing electrode and the cable, flue recirculation, enable the automatic calibration function before replacing components.
E129Safety error for frequently loss of flame with max correction during the ignition during Calibration FunctionCheck the sensing electrode and the cable, flue recirculation, enable the automatic calibration function before replacing components.
E130Flue thermostat sensor tripped (lockout)Check the thermostat, the correct circulation of the water and the pump.
E133Interuption of gas supply or flame failureCheck the power supply, sensing electrode, spark electrode and cable. Check flue recirculation, enable the automatic calibration function before replacing components.
E134Elapsed time gas valve open without gas (short request in a short period)Check the gas pressure, sensing electrode, spark electrode and cable, replace the PCB if necessary.
E135Interuption of gas supply (internal error)Replace PCB.
E154Flow/return sensor temperature test Check the correct circulation of the water and the pump,check the correct position of the sensors.
E160Fan or fan wiring faultCheck the fan and the cable.
E163Domestic Hot Water NTC sensor fault (s.c.)
OR Domestic Hot Water NTC sensor fault (o.c.)
Check the sensor.
E270Circulation fault (dry fire)Check the sensor and the correct circulation of the water and the pump.
E317Wrong power supply electrical frequency (Hz)Check the frequency (Hz) and the power supply.
E321Hot water NTC faultCheck the sensor.
E384False flameCheck the correct operation of the gas valve.
E385Under voltageCheck the power supply (V~).
E430Water pressure temporary testCheck the correct circulation of the water and the pump.
E430 + Flame 'crossed'Water pressure test failedCheck the correct circulation of the water and the pump

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