High Lockout
F7 on Viessmann Vitodens 100-W / 200-W

Your boiler has stopped working because it cannot correctly detect the water pressure, causing the system to shut down for safety.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Burner in fault position. Water pressure sensor fault. Check the sensor and the cable.

What causes this 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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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