Fault 02 Code 255 — Internal fault, controller cannot control heating system

What does Fault 02 255 mean?

The Worcester Bosch Greenstar CDi Boiler displays Fault 02 with code 255, indicating a critical internal fault where the FW 100 or FR110 controller is no longer able to control the heating system.

• Severe internal malfunction of the controller
• Complete failure of the FW 100 or FR110 unit

Click steps to track your progress.

1. 1

   Turn off the boiler's main power supply and wait for 30 seconds, then restart it.

2. 2

   Observe if the fault clears upon restart. If not, the controller may be permanently faulty.

3. 3

   Contact a qualified heating engineer immediately for diagnosis and replacement of the faulty controller.