110 High

Main 110 Fault Code

The Main 110 fault code means: your boiler has switched itself off because it has gotten too hot, likely due to trapped air or a blockage stopping water from circulating properly.. It appears on 5 Main 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: Overheated – try bleeding your radiators
Typical repair cost £100-280 (including labour)

DIY fix possible

Turn off the boiler and allow it to cool down completely.Use a radiator key to bleed all radiators and remove trapped air.Check the boiler pressure gauge and top it up to 1.5 bar if it has dropped.Press the 'Reset' button on the boiler control panel.

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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.

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 7 July 2026