3. The suction pressure is too high
cause of issue:
Excessive opening of expansion valve;
There is a problem with the expansion valve or the position of the temperature sensor is incorrect;
The amount of refrigerant in the system is too large;
Excessive heat load;
The suction valve is broken, high and low pressure blow-by gas;
The safety valve is opened prematurely, and the high and low pressure are bypassed;

Method of exclusion :
Correctly adjust the opening of the expansion valve;
Check the expansion valve to adjust the temperature bulb position;
recovery of excess refrigerant;
try to reduce the heat load;
Check the valve plate and the cause of the blow-by gas;
Adjust the opening pressure of the safety valve;

4. The suction pressure is too low
cause of issue:
Expansion valve opening is small or damaged;
The suction line or filter is blocked;
The temperature sensor leaks;
Insufficient amount of system refrigerant;
Too much lubricating oil in the system;
The evaporator is dirty or the frost layer is too thick;

Method of exclusion:
Open the expansion valve to a suitable position, or replace it;
Check the suction pipe and filter;
Replace the temperature sensor;
supplementary refrigerant;
Overhaul the oil separator to recover excess oil;
cleaning, defrosting,The cooler evaporators ;

5. Exhaust temperature of Cold storage condensers is too high
cause of issue:
The superheat of the inhaled gas is too high;
The suction pressure is low and the compression ratio is too large;
Exhaust valve plate leaks or the spring is damaged;
Abnormal wear and tear of the compressor of condensing unit;
Oil temperature is too high;
The safety valve is opened prematurely, and the high and low pressure are bypassed;

Method of exclusion:
Properly adjust the expansion valve to reduce superheat;
Increase the suction pressure and reduce the compression ratio;
Check and replace the exhaust valve plate and spring;
Check the compressor of condensing unit;
Adjust the opening pressure of the safety valve;
lower oil temperature;