2948 B High

Worcester 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 4 Worcester Bosch models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

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.

Typical repair cost £120-300 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Worcester Bosch models that show the 2948 B fault code

Click a model for the full fault code list and model-specific repair notes.

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 7 July 2026