How much does it cost to fix Heatline error code F04?

Typical repair cost for the Heatline F04 fault is £120-350 including labour.

F04 High

Heatline F04 Fault Code

Q: What does the Heatline F04 fault code mean?

Your boiler has become too hot and has shut itself down for safety, likely because water is not moving through the system correctly.

The Heatline F04 fault code means: your boiler has become too hot and has shut itself down for safety, likely because water is not moving through the system correctly.. It appears on 2 Heatline models in our database.

Technical description: High temperature safety limit (Overheat)

Typical repair cost £120-350 (including labour)

DIY fix possible

Check that all radiator valves are fully openEnsure the boiler pressure is between 1.0 and 1.5 barTry to reset the boiler by turning the control knob to the 'Reset' position for 5 seconds

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Heatline models that show the F04 fault code

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

Source

Heatline F04 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