Under the condition of manually conrolled combustion, if the linked switch of coal feeding is switched to the coal-feeding interlocking position, the two coal feeders will output the same coal feed, and they are only affected by the coal feed amount of #1 coal feeder. Under the condition of automatically controlled combustion, the coal feeding linked switch is in the opposite operating status.  

Alarming and processing of coal feeding interruption:

After the alarm device is put into use for coal feeding interruption, if the coal feeding amount of coal feeder is less than 1.3 t/h,  alarm is given for interruption of coal feeding. When the manual and automatic switch for combustion control is in automatic status, the alarm for coal -interruption is given. DCS system will automatically set the output of coal feeder that coal feed is interrupted to 0, at the same time, if the other coal feeder is in  automatic state, its control output value will be increased. when it is required to put the coal feeder into use again, the alarm for coal feeding interruption must be released, Switch the combustion control to manual operation. Switch the two coal feeders to operating status, manually set the coal amount of coal feeder to appropriate value. At this moment, if the boiler  operates stably, it can be automatically operated again. 

Conditions for Putting-into Use:

1. The system is operating smoothly: The hearth outlet temperature and bed temperature are normal, the changing tendency is smooth, the main steam pressure is within the normal range, and the oxygen content is normal. 

2. The coal feeding amount of single coal feeder is not less than 1.5t/h. 

3. Only the main steam pressure is normal, can the main steam pressure control be put into use. 

Methods for Putting-into Use:

1. Switch the manual and automatic switch for combustion control to " automatic operation". 

2. The main steam pressure control is switched to "automatic operation". 

3. Check whether the working condition of coal feeding and air for returns are normal or not. 

4. Switch the damper adjusting baffle of the primary fan to "automatically status". 

5. Switch the damper adjusting baffle of the secondary fan to "automatically status". 

6. Switch the coal feeder to "automatic" status, at this moment the combustion control is put into use. 

7. As for the automatic operation to manual operation, the manual/ automatic switch for combustion control can be directly switched to manual operation. 

Handling of abnormal situation: 

1. During automatic operation process, if the transmitter is in failure,  it shall be immediately switch back to "manual operated". 

2. If the primary fan, secondary fan and belt conveyor ore-feeder are in failure at this moment, the system shall be switched to "manually-operated". 

3. If the adjusting damper of the fan is in failure,  at this moment, the system shall be switched to "manually-operated". 

4. If the phenomenon of the failure of electric actuator occurs, at this moment, the system shall be switched to "manually-operated". 

5. If the boiler bed temperature  is too high or too low, at this moment, it shall be switched to "manually-operating”. 

6. If the system is de-energized, at this moment, the system shall be switched to "manually-operated".