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How To Solve The Low Pressure Failure During The Chiller Operation?

Jul 20, 2020

How to solve the low pressure failure during the chiller operation?


What will happen to the low pressure failure of the chiller?


   1. Increased energy consumption


  As the compressor runs at low pressure and no-load, the motor load will be reduced. Under the same cooling conditions, a chiller with a low pressure failure will waste electrical energy.


   2. The cooling capacity becomes smaller


   Because the suction pressure of the chiller becomes lower, but the return air volume is small, the cooling capacity will not reach the target cooling, which affects normal use.


  What are the reasons for the low pressure of the chiller? How to solve it?


   No. 1 refrigerant is insufficient or leaking


Insufficient refrigerant will cause the pressure in the system to be abnormal, resulting in a decrease in suction pressure, low-pressure alarm of the chiller, and equipment shutdown. The leakage of refrigerant can be from the compressor, condenser, filter, expansion valve and evaporator, etc. Diagnose the connection of the fittings and pipes. After troubleshooting, fill the appropriate amount of refrigerant to solve the problem. If you don't understand the operation during this process, please contact the chiller manufacturer.


  No.2 The outside temperature is low


   The outside air temperature is low, and the cooling water is turned on at low temperature; or the refrigerating oil temperature is too low, the refrigerator cannot be completely separated, and low pressure failure will occur. If the cooling water temperature is too low, the cooling tower can be closed or the cooling water can be throttled to increase the cooling water temperature. If the temperature of the refrigerating oil is too low, the preheating time of the chiller can be extended, and the refrigerating oil temperature can be solved by returning to normal.


  No.3 system pipe is blocked


   When the chiller is assembled, it is inevitable that impurities will seep into the system. After long use, various impurities will enter the system. At this time, the filter is blocked, the refrigerant throughput is reduced, the return air volume is reduced, and a low pressure failure occurs.


  The solution is to clean the filter, condenser, and evaporator to ensure that the system is free from clogging, and the low pressure failure caused by the clogging of the system pipeline can be eliminated.


   No.4 expansion valve opening is too small or damaged


   Expansion valve is the throttling device of the refrigeration system. If it is too small, it will produce a smaller refrigeration capacity, and if the refrigeration vapor is too little through throttling, it will cause the compressor intake pressure to decrease and cause low pressure failure.


  The solution is to appropriately increase the opening of the expansion valve or replace the damaged expansion valve.


   No.5 relay failure, false alarm of the electrical system


   Relay plays the role of indirect protection equipment. Generally, the normal suction pressure of the compressor is 0.4~0.6MPa. When the suction pressure is lower than 0.2MPa, it will cause the low-voltage protection relay to act, cut off the system circuit and stop the equipment. Sometimes the low-voltage relay will malfunction due to humidity, open circuit, etc., and the system will report low voltage.


  Solution, check the low voltage relay, repair or replace, non-technical personnel can contact the manufacturer for assistance.


   Normally used chillers report a low-voltage failure. Generally, there are several reasons mentioned above. According to the system failure phenomenon, step-by-step investigation will help to quickly find the cause of the failure and resume normal production as soon as possible. When there is a low-pressure failure of the chiller, you can contact the chiller manufacturer for assistance.