Analysis Of 10 Common Faults In Refrigeration Maintenance (I)

- Jul 29, 2019-

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1.Refrigeration system exhaust temperature is too low:


The low exhaust pressure is mainly caused by the small or even stop flow of the refrigerant in the refrigeration system. The exhaust pressure is too low, although the phenomenon is manifested at the high pressure end, but the cause is mostly caused by the low pressure end.


Exhaust pressure is too low Cause:

1). The expansion valve hole is blocked, the liquid supply volume is reduced or even stopped, and the suction and exhaust pressures are reduced at this time.

2), the expansion valve ice block or dirty blockage and filter blockage, etc., will inevitably reduce the suction and exhaust pressure;


2 . Refrigeration system back to liquid:


1). For a small refrigeration system using a capillary: the liquid addition is too large to cause liquid return. When the evaporator is severely frosted or the fan fails, the heat transfer deteriorates, and the unvaporized liquid causes the liquid to return. Frequent fluctuations in temperature can also cause the expansion valve to fail to react and cause backflow.


2). For refrigeration systems using expansion valves: liquid return is closely related to the selection and use of expansion valves. If the expansion valve is too large, the superheat setting is too small, the installation method of the temperature sensor package is incorrect, or the insulation package is damaged, and the expansion valve fails, the liquid return may occur.


For refrigeration systems that are difficult to avoid with liquid return, the installation of gas-liquid separator control can effectively prevent or reduce the hazard of liquid return. 


3 .Refrigeration system high intake temperature:


1). Other causes cause the inspiratory temperature to be too high. If the return air pipe is not well insulated or the pipe is too long, the intake air temperature may be too high. Under normal circumstances, the cylinder head of the compressor should be half cold and half hot.


2). The refrigerant charge in the system is insufficient. Or the expansion valve opening degree is too small, resulting in insufficient circulation of the refrigerant of the system, the refrigerant amount of the evaporator is small, the degree of superheat is large, and the intake temperature is high.


3). The expansion valve port is clogged. The amount of liquid supply in the evaporator is insufficient, the amount of refrigerant liquid is reduced, and a part of the evaporator is occupied by superheated steam, so the intake air temperature is increased.