Your boiler is failing to light the flame needed to provide heating and hot water.

No burner ignition. Possible cause: Excessive condensate level, No gas, Ignition/detection electrode fault, or Faulty gas valve. Cure: Empty / clean the trap, Check the regular gas flow to the boiler and that the air has been eliminated from the pipes, Check the wiring of the electrode and that it is correctly positioned and free of any deposits, Check the gas valve