Your boiler has stopped because the flame went out unexpectedly, which usually happens if the gas supply is interrupted or a safety sensor fails to detect the flame.

Flame failed during burner operation 1. Open the main shut-off valve. 2. Open the appliance shut-off valve. 3. Shut down the appliance and check the gas line. 4. Signal evaluation on printed circuit board defective. 5. Replace the ionisation electrode. 6. Establish protective conductor connection (PE) in the control unit. 7. Replace the ignition cable. 8. Replace the connecting lead to the ionisation electrode. 9. Replace the air/gas ratio control valve. 10.Set the burner correctly. 11.Set the burner at minimum rated load. 12.Check the integrity flue system. 13.The interconnected room air supply is too small or the size of the ventilation opening is too small. 14.Clean the heating block on the flue gas side. 15.Replace the control unit/burner control unit.