How much does it cost to fix Heatline error code F77?

Typical repair cost for the Heatline F77 fault is £250-400 including labour.

F77 High

Heatline F77 Fault Code

Q: What does the Heatline F77 fault code mean?

Your boiler has detected an issue with the valve that controls the supply of gas to the burner, meaning it has safely shut itself down and will not provide heating or hot water.

The Heatline F77 fault code means: your boiler has detected an issue with the valve that controls the supply of gas to the burner, meaning it has safely shut itself down and will not provide heating or hot water.. It appears on 8 Heatline models in our database.

Technical description: Fault in gas valve motor. (Defective gas valve / Defective condensate pump (option))

Typical repair cost £250-400 (including labour)

Engineer required

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

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Heatline models that show the F77 fault code

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

Source

Heatline F77 fault code information on this page is sourced and cross-checked against the official Heatline service / installation manuals for each affected model.

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