How much does it cost to fix Main error code 110?

Typical repair cost for the Main 110 fault is £150-300 including labour.

110 High

Main 110 Fault Code

Q: What does the Main 110 fault code mean?

Your boiler has detected that the water inside the heating system has become too hot and has automatically shut down to prevent damage.

The Main 110 fault code means: your boiler has detected that the water inside the heating system has become too hot and has automatically shut down to prevent damage.. It appears on 1 Main model in our database.

Technical description: Overheat of the primary system water

Typical repair cost £150-300 (including labour)

Engineer required

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

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Main models that show the 110 fault code

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

Insul 7 Repair: £150-300

Source

Main 110 fault code information on this page is sourced and cross-checked against the official Main service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026