BoilerFaultCodesHeatline F85 Fault Code
The Heatline F85 fault code means: your boiler's temperature sensors are reporting conflicting information because they are detecting heat from the same spot, causing the system to stop heating for safety.. It appears on 8 Heatline models in our database.
Technical description: Flow and return heating sensors fault: Flow and return heating temperature sensor connected to same tube
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 F85 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Heatline F85 fault code information on this page is sourced and cross-checked against the official Heatline service / installation manuals for each affected model.
- Heatline CaprizPlus 28 manual (PDF)
- Heatline CaprizPlus 24a manual (PDF)
- Heatline Compact 24 manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026