Many of my friends will encounter such a problem,Starting from the return port of the compressor, frosting toward the evaporator for cold room storage.

Frost begins to form at the air return, which is mainly analyzed from the following two aspects:

1）. Refrigerant

The reason is that too much refrigerant enters the air cooled evaporator, resulting in incomplete evaporation, so the return pipe is still evaporating, absorbing the heat of the suction pipe, so the return pipe is frosted first.

The reasons are:

a. Too much refrigerant;

b. The expansion valve opening is too large;

2）. The evaporator

The air cooler for cold room can not absorb heat normally, or the cold generated by the air cooled evaporator can not be taken away, which will cause incomplete evaporation, and the refrigerant will continue to evaporate and absorb heat in the return air pipe, resulting in frosting of the return air pipe.

The appearance is that the return liquid temperature and pressure are normal or slightly lower, and the frosting starts from the compressor air return port to the evaporator. After a long period of time, it freezes from the compressor air return port to the evaporator and the throttle valve to the evaporator section. , And finally there is low pressure.

The reasons are:

a. Check if the air filter is clean;

b. Check whether the fan speed is normal;

c. Whether the evaporator for cold room storage is clean;

d. Whether the air supply system is blocked;