How much does it cost to fix Worcester Bosch error code HW light On (flashing)?

Typical repair cost for the Worcester Bosch HW light On (flashing) fault is £120-250 including labour.

HW light On (flashing) High

Worcester Bosch HW light On (flashing) Fault Code

Q: What does the Worcester Bosch HW light On (flashing) fault code mean?

Your boiler has sensed that the water inside it is getting too hot and has automatically switched itself off to prevent damage.

Also written as HWLIGHTONFLASHING — same fault.

The Worcester Bosch HW light On (flashing) fault code means: your boiler has sensed that the water inside it is getting too hot and has automatically switched itself off to prevent damage.. It appears on 1 Worcester Bosch model in our database.

Technical description: Over temperature shut-down if water temperature 8°C above set value. Ten second wait.

Typical repair cost £120-250 (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 HW light On (flashing) fault code

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

24CDi BF Repair: £120-250

Source

Worcester Bosch HW light On (flashing) 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