1. Exhaust pressure is too high
cause of issue:
There are non-condensable gases such as air in the system;
Insufficient or too hot cooling water;
The Cold room condensers is dirty and affects heat exchange;
Too much refrigerant in the system;
The exhaust valve is not fully opened or the exhaust pipe is not smooth.

Processing method:
Release air and other non-condensable gases;
Adjust the cooling water volume and reduce the water temperature;
Clean the condenser water process;
recovery of excess refrigerant;
Fully open the exhaust valve to clear the exhaust pipe.

Non-condensable gas hazards:

lead to an increase in condensing pressure;
The formation of air resistance reduces the heat transfer efficiency of the condenser. Simultaneous corrosion of pipes and equipment;
lead to a decrease in cooling capacity and an increase in power consumption;
If there is air, accidents are prone to occur when the exhaust temperature is high.

Judgment method of non-condensable gas:
The pointer of the exhaust pressure gauge of the refrigerator oscillates;
Exhaust pressure and exhaust temperature are greater than normal pressure and temperature;
Air is lighter than fluorine gas, so air exists in the upper part of the horizontal condenser. When venting, the air is not cool.

Reasons for non-condensable gas entering the system:
Incomplete vacuuming;
The air is not exhausted during maintenance, for example, the fluorine pipe is not exhausted when adding fluoride;
The pressure of the low-pressure part of the refrigeration system is in negative pressure for a long time;
The refrigerant itself is not pure and contains air or impurities;
At high temperature, oil decomposes into non-condensable gas;

Hazards of excess refrigerant:
Excessive refrigerant will occupy part of the condenser volume, reduce the heat transfer area, and cause the condensation temperature and pressure to be too high;
The evaporating temperature of the air cooler evaporators, the evaporating pressure rises, and the cooling effect decreases;
Inspiratory pressure too high;
Excessive refrigerant, refrigerant liquid enters the compressor, causing wet compression or even liquid hammer;
The starting load is heavier, and the motor is difficult to start.

2. Exhaust pressure is too low
cause of issue:
The cooling water temperature is too low or the water volume is too large;
The compressor of condensing units discharge valve is damaged or the discharge pipeline leaks;
Insufficient amount of refrigerant in the system;
Improper adjustment of the energy adjustment mechanism;
The safety valve is opened prematurely, and the high and low pressure are bypassed;

Method of exclusion:
Adjust the water supply;
Check the exhaust valve and exhaust pipe;
make-up refrigerant;
Adjust the adjustable mechanism to make it normal;
Adjust the opening pressure of the safety valve;