A2 High

Worcester Bosch A2 Fault Code

The Worcester Bosch A2 fault code means: your boiler is struggling to accurately measure the temperature of the water it is heating, so it has stopped providing hot water to be on the safe side.. It appears on 1 Worcester Bosch model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Hot water NTC sensor defective. Check hot water NTC sensor and connecting lead for circuit breaks/short circuits.
Typical repair cost £120-200 (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 A2 fault code

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

Source

Worcester Bosch A2 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 7 July 2026