P3 High

Worcester Bosch P3 Fault Code

The Worcester Bosch P3 fault code means: your boiler's internal electrical circuit has lost power because a small safety fuse has blown, preventing the system from starting up.. It appears on 11 Worcester Bosch models 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: Please wait, initialisation in progress. 24 V fuse blown. Replace fuse.

What causes the Worcester Bosch P3 fault?

This fault occurs when an electrical surge or a short circuit within the boiler's internal components causes a small safety fuse to blow. The most common reason is a failing internal component, such as a sensor or the main pump, drawing too much power and triggering the fuse to protect the expensive control board. It acts like a household trip switch, cutting power instantly to prevent further electrical damage.

Typical repair cost £90-180 (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 P3 fault code

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

Source

Worcester Bosch P3 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