How much does it cost to fix Heatline error code F08?

Typical repair cost for the Heatline F08 fault is £90-160 including labour.

F08 High

Heatline F08 Fault Code

Q: What does the Heatline F08 fault code mean?

Your boiler's internal thermometer has stopped working correctly, meaning the system can no longer accurately monitor the temperature of the water being sent to your radiators.

The Heatline F08 fault code means: your boiler's internal thermometer has stopped working correctly, meaning the system can no longer accurately monitor the temperature of the water being sent to your radiators.. It appears on 2 Heatline models in our database.

Technical description: Central heating flow thermistor (NTC) sensor fault

Typical repair cost £90-160 (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 F08 fault code

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

Source

Heatline F08 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