How much does it cost to fix Worcester Bosch error code 338 F0?

Typical repair cost for the Worcester Bosch 338 F0 fault is £150-300 including labour.

338 F0 High

Worcester Bosch 338 F0 Fault Code

Q: What does the Worcester Bosch 338 F0 fault code mean?

Your boiler is repeatedly trying to start up its flame but failing to detect that water is circulating through the system, causing it to lock itself to prevent damage.

Also written as 338F0 — same fault.

The Worcester Bosch 338 F0 fault code means: your boiler is repeatedly trying to start up its flame but failing to detect that water is circulating through the system, causing it to lock itself to prevent damage.. It appears on 2 Worcester Bosch models in our database.

Technical description: Too many short burner starts without confirmation of water flow

Typical repair cost £150-300 (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 338 F0 fault code

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

Source

Worcester Bosch 338 F0 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