Excessive pressure drop at the inlet and outlet of the air dryer

Failure situation: There is a pressure difference between the inlet pressure and the outlet pressure of the refrigerated air dryer.
Cause one: The evaporator's evaporation temperature is too low, causing ice inside the evaporator;
Cause two: The diameter of the compressed air pipeline is smaller than the diameter of the air inlet and outlet of the dryer;
Cause three: There are too many corners in the compressed air pipeline;
Cause four: The precision filter element is blocked;
Cause five: The inlet and outlet valves are not all open;
Cause six: The compressed air configuration pipeline is too long.