522 Low

Worcester Bosch 522 Fault Code

The Worcester Bosch 522 fault code means: your boiler is currently performing a routine self-check of its temperature sensors to ensure it is operating safely and accurately.. It appears on 3 Worcester Bosch models 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: NTC Drift Test is running

What causes the Worcester Bosch 522 fault?

Sensor calibration test

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 522 fault code

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

Source

Worcester Bosch 522 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