BoilerFaultCodesWorcester Bosch 2948 B Fault Code
Also written as 2948B — same fault.
The Worcester Bosch 2948 B fault code means: your boiler is struggling to keep its flame lit during operation, which is causing it to stop and restart frequently.. It appears on 12 Worcester Bosch models in our database.
Technical description: No flame signal. With low output the burner starts automatically after cleaning. If the fault occurs repeatedly, the setting of the CO2 valves need checking
What causes the Worcester Bosch 2948 B fault?
This fault occurs when the boiler's internal sensors lose track of the flame while it is firing at a low power level. It is usually caused by a dirty or worn flame sensor that can no longer 'see' the fire, or a gas valve that isn't delivering the precise amount of fuel needed to maintain a stable small flame.
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 2948 B fault code
Click a model for the full fault code list and model-specific repair notes.
- 24 RSF Repair: £90-250
- 26 CDi Xtra Repair: £120-350
- 30i Junior Repair: £90-250
- 35 RSF Repair: £120-280
- Danesmoor Repair: £120-350
- Greenstar 2000 Repair: £120-280
- Greenstar 8000 Life System Repair: £180-350
- Greenstar 8000 Life/Style Repair: £120-300
- Heatslave Repair: £120-350
- Hideaway Repair: £90-250
- Junior 24i Repair: £100-280
- Junior 28i Repair: £120-280
Source
Worcester Bosch 2948 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