How much does it cost to fix Worcester Bosch error code CH light On?

Typical repair cost for the Worcester Bosch CH light On fault is £120-250 including labour.

CH light On High

Worcester Bosch CH light On Fault Code

Q: What does the Worcester Bosch CH light On fault code mean?

Your boiler has automatically turned itself off because the water inside it is getting too hot, likely due to a circulation problem.

Also written as CHLIGHTON — same fault.

The Worcester Bosch CH light On fault code means: your boiler has automatically turned itself off because the water inside it is getting too hot, likely due to a circulation problem.. It appears on 2 Worcester Bosch models in our database.

Technical description: Over temperature shut-down if flow temperature 5°C above set value

Typical repair cost £120-250 (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 CH light On fault code

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

Source

Worcester Bosch CH light On 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