3 flashes Medium

Worcester Bosch 3 flashes Fault Code

Also written as 3FLASHES — same fault.

The Worcester Bosch 3 flashes fault code means: your boiler is having trouble measuring the temperature of your hot water, which usually means your taps will only provide cold or lukewarm water.. It appears on 3 Worcester Bosch models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Hot water NTC sensor defective.
Typical repair cost £90-160 (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 3 flashes fault code

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

Source

Worcester Bosch 3 flashes 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