||Possible solution / cause
||Heat exchanger sensor needs replacing.
||Temperature too high during central heating demand
||Air could be in system, central heating system needs bleeding. There could be an error with the pump & it could need replacing.
||Temperature too high during domestic hot water (DHW) demand
||The wiring of DHW sensor needs checking, possible breakage.
||Flue gas temperature too high
||Heat exchanger needs checking for contamination.
||No flame during startup
||Gas valve is closed. Condensation drain is blocked and ignition needs checking.
||Flame disappears during operation
||Condensation drain could be blocked, the air supply duct and flue needs checking for possible recirculation or blockage of flue gases.
||Flame simulation error
||Gas valve could need replacing or burner controller could need replacing.
||No or insufficient ionisation flow
||Wiring of ionisation/ignition pin could have a breakage shut down and could need replacing.
||Fan speed incorrect
||Fan cable needs checking, fan or burner controller could need replacing.
||Bunner controller has internal fault
||Burner controller needs replacing.
||Possible issue with heat exchanger sensor, breakage or not connected properly.
||Sensor 5 fault
||Wiring for flue gas sensor needs checking, possible breakage.
||Mounting fault sensor
||Heat exchanger sensor is not mounted correctly and needs to be mounted properly.
||Mounting fault sensor S1
||Central heating flow sensor is not mounted correctly and needs mounting properly.
||Mounting fault S3
||Domestic hot water sensor is not mounted correctly and needs mounting properly.
||Flue and / or air supply duct is blocked
||The flue and/or air supply duct could need cleaning.
||Check the BMM wiring for breakages / BMM wiring could need replacing.
||Short circuit of outdoor sensor
||Outdoor sensor could have a wiring issue, check and replace the outdoor sensor.
||The reset button needs checking for unintentional operation e.g. cleaning of control panel. Burner controller might need replacing.
||Gas valve error
||Gas valve needs checking for leakage / burner controller could need replacing
||Sensor S3 fault
||Check wiring of domestic hot water sensor for breakage or shutdown domestic hot water sensor – it could need replacing.
||Sensor fault S1
||Check wiring of central heating flow sensor for breakage and shutdown. Check that weather central heating flow sensor is connected correctly.