How much does it cost to fix Heatline error code F09?

Typical repair cost for the Heatline F09 fault is £90-160 including labour.

F09 High

Heatline F09 Fault Code

Q: What does the Heatline F09 fault code mean?

Your boiler's internal computer has lost track of the temperature of the water coming back from your radiators, causing the system to stop working for safety.

The Heatline F09 fault code means: your boiler's internal computer has lost track of the temperature of the water coming back from your radiators, causing the system to stop working for safety.. It appears on 2 Heatline models in our database.

Technical description: Central heating return 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 F09 fault code

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

Capriz Plus Repair: £120-180
Vizo Plus Repair: £90-160

Source

Heatline F09 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