Worcester Bosch Error Codes

These Worcester Bosch boiler fault codes help diagnose common issues such as ignition problems, low water pressure, sensor faults, and overheating, providing a quick reference for troubleshooting and maintenance.

EA
Meaning: No flame detected
Possible Cause / Fix: Gas supply issue, blocked flue, or faulty ignition – try resetting the boiler.

E9
Meaning: Overheat
Possible Cause / Fix: Blocked heat exchanger or faulty temperature sensor – call a heating engineer.

E5
Meaning: Fan or Air Pressure Fault
Possible Cause / Fix: Fan not running or issue with air pressure switch – engineer needed.

D1
Meaning: Sensor fault
Possible Cause / Fix: Flow temperature sensor error – check sensor or wiring.

C6
Meaning: Fan running slowly
Possible Cause / Fix: Fan fault or motor issue – technician needed.

A1
Meaning: Low water pressure
Possible Cause / Fix: Check pressure gauge (should be 1–1.5 bar) – repressurise if needed.

A7
Meaning: DHW sensor fault
Possible Cause / Fix: Domestic hot water sensor problem – replace sensor.

CE 207
Meaning: Heat Control Module fault
Possible Cause / Fix: PCB issue or communication error – may need parts replaced.