4-A6 Low

Worcester Bosch 4-A6 Fault Code

Also written as 4A6 — same fault.

The Worcester Bosch 4-A6 fault code means: your boiler is simply reminding you that its scheduled service is due based on the time interval set by your engineer.. It appears on 1 Worcester Bosch model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Inspection interval according to elapsed time: 1... 72 months.
Typical repair cost £80-120 (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 4-A6 fault code

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

Source

Worcester Bosch 4-A6 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