1. The circulating  water volume is in shortage: Under the same load, the inlet and outlet temperature difference of the  circulating water of the condenser  increases, the reason may be that the impurities enters the condenser and causes jamming. For a unit with rubber ball for cleaning, it shall be backflushed.For the unit that the condenser outlet pipe is provided with siphon, it shall be checked whether the siphon is destroyed or not,  the phenomenon damage is: The vacuum at the condenser exit is zero, in the same time the condenser inlet pressure increases. In case the above mentioned situation appears, the auxiliary extractor of the circulating water system shall be used to recover the vacuum at the exit.  When necessary, the condenser circulating water shall be increased. The condenser exit temperature difference increases,  this is because that air accumulates at the circulating water outlet pipe or the copper tube scales seriously. At this moment, open the air bleeding valve of the outlet pipe to exhaust the air or put the rubber ball cleaning device for cleaning and, when necessary, during downtime use high pressure water to flush.
2. The condenser water level rises: which is because the vaporization happens at the condenser water pump inlet  or the copper pipe of the condenser cracks and the circulating water leaks etc..Vaporization at the condenser water pump inlet van be judged from the  decreasing of the condensate pump current. When it is confirmed that the condenser water level rises due to this reason, it is required to check the flange packing of the water pump inlet is tight or not and whether air leaks or not. The condenser copper pipe cracking can be judged by inspecting the  hardness of the condensed water.
3. Working water temperature of the water jet air ejector rises: The working temperature rises, so the suction chamber pressure rises, thus the efficiency of the air extractor is reduced. When the water temperature is found to rise, the industrial make-up water shall be opened to reduce water temperature.
4. The vacuum system leaks:  Whether the vacuum system leaks can be checked by the tightness test. In addition, in case the air leaks to vacuum system, it is shown that the condensate super cooling degree increases and the condenser end difference increases.