Boiler shows F10, no burner operation

Safety: Do not overfill the system. Overpressure can cause leaks.

• Check pressure gauge: On the front panel, verify pressure is typically between 1.0 and 1.5 bar when cold.
• Top up system: Use the Viessmann filling loop or integrated filling device to slowly add water until the correct pressure is reached. Close valves securely afterwards.
• Bleed radiators: After filling, bleed air from radiators and recheck pressure.
• Inspect for leaks: Look around radiators, valves, and under the boiler for signs of water loss.
• Pressure sensor check: If pressure is correct but F10 remains, the water pressure sensor may be faulty and should be tested/replaced by a technician.