Worcester Bosch Boiler Faults & Common Errors
Has a fault developed on your Worcester Bosch Boiler? If your boiler has an issue then it will enter a safe lock-out mode and provide an error code.
In order to help you determine what this error code could mean we have generated descriptions for each of them below. If you are still unable to fix the issue then please don't hesitate to get in contact with one of our expert boiler engineer partners who can help fix your heating troubles.
General Faults & Errors
This section is an overview of all of the types of errors that can occur on a Worcester Bosch boiler.
| Issue | Description |
|---|---|
| Blocking Errors | If this occurs then there will be no fault data displayed and the boiler will cease operating. You can find the cause of this in the info menu which is accessed by pressing the spanner or return button on your boiler. When the fault clears the condition will clear automatically, such as if you wait for an area to cool. It can be found that in some cases a blocking error has a time duration before it changes to a locking condition. |
| Cause Error | A cause error is a three digit number which is displayed, however during a blocking error it won't appear, although you can still access the information from the menu. |
| Fault Error | This is an alpha numeric code that indicates the fault group. |
| Locking Error | When there is a locking error the boiler flashes with a warning triangle and a fault code at the same time. The cause code will be displayed and in order to clear the fault you will need to manually press the reset button on the boiler fascia. |
| Maintenance Codes | These are codes that are displayed with the letter H which is then followed by a number. The code advises the situation but will not stop your boiler from working. Maintenance code list below. |
Locking Errors
Here is a list of the fault codes that occur for a Worcester Bosch locking error, most of these are fixed by the reset button with the exception of B7.
| Fault Codes | Cause Codes | Description | Potential Cause |
|---|---|---|---|
| 9A | 362 | Heat Control Module (HCM) | HCM fitted incorrectly |
| 9U | 233 | Heat Control Module (HCM) | Faulty or not connected code plug |
| B7 | 257 | Internal error | Replace control board |
| C6 | 215 | Fan issue | The fan is running too fast |
| C6 | 216 | Fan issue | The fan is running too slow |
| C7 | 214 | Fan issue | The fan is not running |
| C7 | 217 | After a defined period of time there is no airflow | The fan is not running or the airflow has been blocked |
| D1 | 240 | Error for return sensor | Sensor wet or damaged (the boiler will block for 300 seconds before this condition) |
| D1 | 241 | Error for return sensor | Sensor disconnected or damaged (the boiler will block for 300 seconds before this condition) |
| D1 | 286 | The temperature of return is too high | Overheating boiler |
| E2 | 222 | Short circuit flow sensor | Damaged or flow sensor disconnected |
| E2 | 223 | Open circuit flow sensor | Disconnected or damaged flow sensor |
| E5 | 218 | Flow temperature too high | Primary flow sensor overheat |
| E5 | 332 | 110C temperature limit has been exceeded on the primary flow sensor | Primary flow sensor overheat |
| E9 | 219 | Temperature too high on safety sensor | There is a maximum temperature of 105C, this means that the heat exchanger has exceeded this. |
| E9 | 220 | Short circuited safety sensor | Maximum temperature sensor on the main heat exchanger has failed |
| E9 | 221 | Open circuit on the safety sensor | Maximum temperature sensor on the main heat exchanger has not been recognised |
| E9 | 224 | The max temperature thermostat has been activated | Overheated flue gas thermostat |
| EA | 227 | After the ignition no flame has been detected | This error occurs after the failure of four ignition attempts. There is a 30 second wait between each attempt. |
| EA | 229 | During operation there has been a loss of flame signal | The established flame has been extinguished which could be caused by moisture in the stump or a strong wind into the flue |
| EA | 234 | Error in the gas valve | Gas valve coil disconnected |
| EA | 261 | Timing error on ignition | During the first 4 seconds of the ignition period a flame was not established |
| EA | 338 | Too many short burner starts without confirmation | The pump is not detecting water, you need to check the pressure gauge and repressurise to 1 bar |
Blocking Errors
If this occurs then there will be no fault data displayed and the boiler will cease operating. You can find a list of the block errors for Worcester Bosch boilers in the table below:
| Fault Codes | Cause Codes | Description | Potential Cause |
|---|---|---|---|
| A1 | 281 | Running in air or the pump could be stuck | Check the pressure gauge and re pressurise to 1 bar as there is little or no water in the system |
| C1 | 264 | During operation the airflow has stopped | The fan has stopped working |
| EA | 227 | After ignition no ionisation has been detected | The boiler blocks at 4 attempts of ignition before going to locking fault. No flame is detected. |
| EF | 349 | Central heating, boil detect. Large delta T despite minimum burner. | There is a greater than 18C Return & Flow temperature difference so the boiler is operating at minimum burner load |
| N/A | 212 | Flow temperature has risen too fast | Check the pressure gauge and re pressurise to 1 bar as there is an air lock or reduced water content |
| N/A | 213 | The difference in temperature between the supply and return exceeds the limit | Check the pressure gauge and re pressurise to 1 bar as there is an air lock or reduced water content |
| N/A | 260 | No temperature rise after burner starts | Check the pressure gauge and re pressurise to 1 bar as the sensor has disconnected or there is no water content |