BoilerFaultCodesWorcester Bosch 2963 B Fault Code
Also written as 2963B — same fault.
The Worcester Bosch 2963 B fault code means: your boiler has detected an unusual temperature reading because a sensor or its wiring is not communicating correctly with the main control unit.. It appears on 13 Worcester Bosch models in our database.
Technical description: Signal from flow and heat exchanger temperature sensor outside the permissible range – the connecting lead needs connecting correctly
What causes the Worcester Bosch 2963 B fault?
This fault occurs when the boiler's central control board receives an impossible temperature reading from the internal sensors. This is usually caused by a loose connection in the internal wiring or a sensor that has physically failed, meaning the boiler can no longer safely monitor the water temperature inside the heat exchanger.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Worcester Bosch models that show the 2963 B fault code
Click a model for the full fault code list and model-specific repair notes.
- 24 RSF Repair: £90-180
- 26 CDi Xtra Repair: £120-£240
- 30i Junior Repair: £90-180
- 35 RSF Repair: £90-180
- Danesmoor Repair: £90-180
- Greenstar 2000 Repair: £220-450
- Greenstar 4000 Repair: £150-250
- Greenstar 8000 Life System Repair: £150-250
- Greenstar 8000 Life/Style Repair: £90-180
- Heatslave Repair: £95-210
- Hideaway Repair: £90-180
- Junior 24i Repair: £90-180
- Junior 28i Repair: £90-180
Source
Worcester Bosch 2963 B fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026