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boiler service, boiler repair, emergency repair
Worcester Greenstar 28 CDi Compact LPG ErP Boiler Fault Codes
Locking Error
The boiler display will flash a warning triangle and fault code. At the same time a (static) cause code will also be displayed. Manual intervention is required following clearance of the fault: ▶ Press the reset button on the boiler fascia.
Blocking Error
The boiler will stop operating with no fault data displayed. The cause code, in the info menu, is accessed by pressing the spanner/return button. The condition will clear automatically when the associated fault clears e.g. waiting for an area to cool. In some cases a blocking error has a defined time duration prior to changing to a locking condition.
| Locking Errors | ||||
| Fault Code | Cause Codes | Description | Reset Type | Possible Cause |
| 9U | 233 | HCM (Heat Control Module) | Reset button | Problem with the code plug |
| b7 | 257 | Internal error | Replace control board. | |
| C6 |
215 216 |
Fan problem Fan problem |
Reset button Reset button |
Fan running too fast Fan running too slow |
| C7 |
214 217 |
Fan problem No airflow after a defined period of time |
Reset button Reset button |
Fan not running Fan not running or airflow blocked |
| D1 |
240 241 286 |
Return sensor error Return sensor error Return temperature too high |
Reset button Reset button Reset button |
Sensor wet or damaged (the boiler will block for 300 secs before this condition). Sensor disconnected or damaged (the boiler will block for 300 secs before this condition). Boiler overheat |
| E2 |
222 223 |
Flow sensor short circuit Flow sensor open circuit |
Reset button Reset button |
Flow sensor shorted or damaged. Flow sensor disconnected or damaged. |
| E5 |
218 332 |
Flow temperature too high Primary flow sensor has exceeded 110°C |
Reset button Reset button |
Primary flow sensor overheated Primary flow sensor overheated |
| E9 |
219 220 221 224 |
Safety sensor temperature too high Safety sensor short circuit Safety sensor open circuit Max temperature thermostat activated |
Reset button Reset button Reset button Reset button |
The main heat exchanger has overheated. Maximum temperature 105C° Maximum temperature sensor on the main heat exchanger has failed. Maximum temperature sensor on the main heat exchanger has not been recognised. Flue gas thermostat overheat |
| EA |
227 229 234 261 |
No flame detected after ignition Loss of flame signal during operation Gas valve error Ignition timing error |
Reset button Reset button Reset button Reset button |
Failure of four ignition attempts. The boiler waits 30 seconds before another attempt is made An established flame has been extinguished. This could be caused by: • moisture in the sump, due to a blocked sump/condensate trap. • a strong wind into the flue. Gas valve coil disconnected Flame not established during the first 4 seconds ignition period. |
| F0 |
237-239 242-256 258 259 262 263 267 272 279 290 |
Internal error | Call Worcester, Bosch Group Technical helpline 0330 123 3366 | |
| 278 | Sensor test failed | Reset button | On power up all safety sensors are checked. Check has failed. | |
| 280 | Recycle time error | Reset button | After the burner has stopped, the recycle mode purges gas from the heat exchanger before attempting to burn again. The software has 3.1 seconds to intervene before the boiler goes into this fault condition. | |
| 338 | Too many short burner starts without confirmation | Reset button | There is an error where the pump is not detecting water. | |
| F7 | 228 | Flame error | Reset button | False flame. Flame detected before burner start. |
| 328 | Internal error | Replace control board | ||
| FA | 306 | False flame error | Reset button | Flame detected after burner stop |
| FD | 231 | Mains power error | Reset button | Electrical power interruption. |
| FA | 364 | Gas valve EV2 leak test failed | Reset button | Gas valve leak. |
| Fb | 365 | Gas valve EV1 leak test failed | Reset button | Gas valve leak. |
| Fault Code | Cause Code | Description | Possible Cause |
| A1 | 281 | Pump stuck or running in air | Little or no water in the system. |
| C1 | 264 | Airflow stopped during operation | Fan has stopped. |
| C4 | 273 | Airflow present during last 24 hours | Fan has been running continuously during the past 24 hours. |
| D1 |
240 241 |
Return sensor short circuit Return sensor disconnected |
Wet sensor. Blocking for 300 secs before going to Locking error. Blocking for 300 secs before going to Locking error. |
| D4 | 271 | Temperature difference between flow and safety sensors exceeds limit | The temperature of the primary flow and the safety sensor on the WB7 should be within 15°C of each other. |
| E9 |
224 276 277 285 |
MAX thermostat activated Flow temperature exceeds 95°C Safety temperature exceeds 95°C Return temperature exceeds 95°C |
Flue gas thermostat overheat. Primary overheat - boiler waits for temperature to reduce; if not it becomes a Locking error. Main heat exchanger safety sensor overheat - boiler will wait for the temperature to reduce; if not it becomes a Locking error 219. The boiler will stop the burn and wait to see if it cools down. If after 2 seconds there is an increase in temperature the boiler will go to Locking error 286. |
| EA | 227 | No ionisation detected after ignition | No flame is detected. The boiler will block during 4 attempts before going to Locking fault. |
| EF | 349 | Central heating, boil detect. Large delta T despite minimum burner. | The boiler is operating at minimum burner load and there is a greater than 18°C Flow & Return temperature difference. |
| No code |
212 213 260 380 |
Safety or flow temperature rises too fast Temperature difference between supply and return exceeding limit No temperature rise after burner starts Inlet DHW temperature higher than the DHW outlet temperature. |
Air lock or reduced water content. Air lock or reduced water content. Sensor disconnected or no water content. The output is blocked until the inlet temperature drops below the output temperature. |