1. When each protective device doesn’t act normally;
2. When the automatic main steam valve, steam control valve and steam extraction check valve are not closed tightly or jammed;
3. When the regulating system cannot maintain the unit to operate with no-load or cannot control the rotating speed of the unit after load rejection;
4. When any oil pump is in failure and the auxiliary equipment cannot operate normally;
5. When the key meters are abnormal( such as tachometer, steam temperature-steam pressure meter, lubrication oil pressure meter and vacuum meter etc.);
6. When the lubrication oil quality is unqualified;
7. The rotating part of the turbonator has obvious metal friction noise.