Conditions for Putting-into Use:

1. The negative pressure of boiler hearth reaches the normal range of working condition. 

2. The boiler is operating stably. 

3. The DCS system is operating stably. 

4.When the above conditions are reached, the hearth negative pressure control device for controlling the boiler hearth can be automatically put into use. (note that if the opening of the induced draft fan baffle is greater than 90%, the baffle shall be manually operated). 

Methods for Putting-into Use:

Switch the hearth negative pressure control to automatic control.  

From automatic operation to manual operation: 

Switch the hearth negative pressure control to manual control.  

Handling of abnormal situation: 

1. During automatic operation process, if the transmitter is in failure (the measurement of boiler hearth seriously deviates), it shall be immediately switched back to "manual operated". 

2. If the boiler load change is too big, the negative pressure of  boiler hearth automatic controlled will vibrate, at this moment, it shall be immediately switched back to "manual operated" . 

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

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

5. If the electric actuator is in failure, at this moment, the system shall be switched to "manually-operated". 

6. If the negative pressure of boiler hearth is too high or too low, at this moment, it shall be switched to "manually"operating. 

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