O2 control is released when all of the following conditions are met:

• The burner fires.

• The delay time for control release Delay time - control release after burner is firing, after a fuel change and after additional fuel activation or deactivation has expired.

• The burner capacity is within the allowable activation and shut-down limits.

• The maximum load change does not exceed the value from parameter Deactivation at load difference.

• O₂ correction was switched on in the operation mode using parameters O2 correction in operation mode: Used.

• The O₂ setpoint curve was entered completely in the active operation mode.

• The setup mode is not active.

• The O₂ alarms for purging, ignition, MIN1, MIN2 and probe are not pending.

• Flue gas recirculation has been released when a channel with flue gas recirculation is active in the operation mode.