Worcester Bosch Boiler Fault Codes Explained
Worcester Bosch fault codes tell you which part of the boiler has a problem — but they don't tell you how to fix it safely. Here's what each common Greenstar code means, what you can check yourself, and when to call a Gas Safe engineer.
EA 229 Fault
No flame / flame lost — ionisation signal insufficient. Often frozen condensate or gas supply.
CE 207 Fault
System water pressure too low — boiler can't confirm there's enough water to run safely.
E9 219 Fault
Safety overheat lockout — heat exchanger exceeded 105°C. Usually a pump or circulation fault.
C6 215 Fault
Fan speed out of range — boiler can't confirm flue gases are being safely expelled.
When to call a Gas Safe engineer
Any work inside the boiler casing — replacing the fan, pump, ionisation electrode, gas valve, pressure sensor or PCB — is gas work that must be done by a Gas Safe Registered engineer. The safe checks on each fault-code page are limited to what you can do without opening the boiler.
If you can smell gas, turn off the gas at the meter, open windows, don't use switches, and call the National Gas Emergency Service on 0800 111 999 immediately.