How much does it cost to fix Worcester Bosch error code 4-A5?

Typical repair cost for the Worcester Bosch 4-A5 fault is £80-120 including labour.

4-A5 Low

Worcester Bosch 4-A5 Fault Code

Q: What does the Worcester Bosch 4-A5 fault code mean?

Your boiler is simply letting you know that it has reached its scheduled running time and is now due for a routine service.

Also written as 4A5 — same fault.

The Worcester Bosch 4-A5 fault code means: your boiler is simply letting you know that it has reached its scheduled running time and is now due for a routine service.. It appears on 1 Worcester Bosch model in our database.

Technical description: Inspection interval according to hours run: 10 ...60 x 100 hours.

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-A5 fault code

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

Greenstar 2000 Repair: £80-120

Source

Worcester Bosch 4-A5 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