BoilerFaultCodesViessmann F7 Fault Code
The Viessmann F7 fault code means: your boiler has stopped working because it cannot correctly detect the water pressure, causing the system to shut down for safety.. It appears on 8 Viessmann models in our database.
Technical description: Burner in fault position. Water pressure sensor fault. Check the sensor and the cable.
What causes the Viessmann F7 fault?
This fault occurs when the boiler's internal computer loses communication with the electronic component that monitors system pressure. The most common reason is that the sensor itself has failed internally or the electrical wiring connecting it to the main control board has become loose or damaged. Because the boiler cannot confirm there is enough water to operate safely, it shuts down to prevent the system from overheating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Viessmann models that show the F7 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Viessmann F7 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
- Viessmann Vitodens 100-W manual (PDF)
- Viessmann Vitodens 100-W WB1A manual (PDF)
- Viessmann Vitodens 300-W manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026