275 High

Worcester Bosch 275 Fault Code

The Worcester Bosch 275 fault code means: your boiler has accidentally been left in a restricted diagnostic mode used by engineers during installation, meaning it cannot currently heat your home or water.. It appears on 6 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: Boiler electronics in test mode

What causes the Worcester Bosch 275 fault?

Test mode active

Typical repair cost £80-150 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Worcester Bosch models that show the 275 fault code

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

Source

Worcester Bosch 275 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