Worcester Bosch is one of the most widely installed boiler brands in the UK. This page collects our guides and the common Worcester Bosch combi boiler fault codes, with what each one means and what you can safely check yourself.
Worcester Bosch combi boiler error codes
- 1017 W Water pressure too low
- 224 V Safety temperature limiter tripped
- 227 V No flame signal after ignition
- 9U 233 Heat control module (HCM) code plug faulty or disconnected
- A1 281 Pump stuck or running in air (little or no water in the system)
- B7 257 Internal error on the control board
- C1 264 Airflow stopped — the fan has stopped during operation
- C6 214 Fan not running
- C6 215 Fan running too fast
- C6 216 Fan running too slow
- CE 207 Low water pressure
- D1 240 Return temperature sensor wet or damaged
- D1 241 Return temperature sensor disconnected or damaged
- E2 222 Flow temperature sensor short circuit
- E2 223 Flow temperature sensor disconnected or damaged
- E5 218 Primary flow temperature too high
- E9 219 Heat exchanger overheated (safety limit reached)
- E9 224 Flue gas overheat — maximum thermostat activated
- EA 227 No flame detected after ignition
- EA 229 Flame lost during operation
- EA 234 Gas valve coil disconnected
- EA 261 Flame not established within the first seconds of ignition
- EA 338 Too many short burner starts — pump not detecting water
- EF 349 Flow and return temperature difference too large at minimum burner output
- F7 228 False flame — flame detected before the burner started
- FA 306 Flame detected after the burner stopped
- FD 231 Mains power interruption
- H11 Hot water outlet sensor defect
- H13 Annual service reminder
Should you repair or replace?
As a rough rule, if your boiler is more than 10–12 years old and the repair is over a few hundred pounds, it's worth getting a replacement price before you commit. Parts for older models also get harder to find.
Get a fixed quote
One local Gas Safe installer, chosen for your postcode. Free and no obligation.