Worcester Bosch Error Code Leave a Comment / Boiler Fault Codes / By Emergency Plumbers / May 3, 2015 May 3, 2020 / Worcester Bosch Error Code Worcester Bosch Error Code Fault Code Possible Cause A1 Little or no water in the system – check pressure gauge and repressurise to 1 bar. C1 Fan has stopped EA No flame is detected. The boiler will block during 4 attempts before going to Locking fault EF The boiler is operating at minimum burner load and there is a greater than 18°C Flow & Return temperature difference No Code Air lock or reduced water content – check pressure gauge and re-pressurise to 1 bar 260 Sensor disconnected or no water content – check pressure gauge and re-pressurise to 1 bar