1.When the boiler lacks water severely and the water level is not shown when the “Water-feeding to the Boiler”method is used.

2.When the boiler is full of water severely and the water is not shown when the “Water-feeding to the Boiler ”method is used.

3.When the boiler pipe breaks and the normal water level of boiler drum cannot be maintained。

4.When the fuel burns secondarily inside the back chimney flue，so that the exhaust gas temperature rises abnormally。

5.When all the water level gauges are damaged.

6.When the boiler steam-water pipe breaks and the personal and equipment safety are threatened.

7.When the boiler is over-pressurized, the safe valve refuses to act and the exhaust valve cannot be opened.

8.When the fluidized bed cokes severely and normal combustion cannot be maintained.

9.When the slag discharging pipe breaks and the differential pressure of the bed of materials cannot be maintained. 

10.When fire goes out due to various reasons.

11.When the cyclone separator or cyclone drum are severely worn, so that the guard plate or cross beam are burned red.

12.When the induced draft fan and forced draft fan are damaged severely and the fan motor fires.

13.DCS system is abnormal and cannot be monitored.