During more than ten years of refrigerator maintenance in Linyi Communications Refrigeration Engineering Co., Ltd., the refrigerator maintenance master has accumulated rich experience in refrigerator maintenance. Among the common refrigerator maintenance faults, high-voltage faults occur frequently. Below, we will introduce the reasons for high-voltage faults.The compressor exhaust pressure of cold storage equipment is too high, which leads to the action of high voltage protection relay. The compressor discharge pressure reflects the condensation pressure, the normal value should be 1.4~1. 6MPa, and the protection value should be set at 2.0MPa. If the pressure is too high for a long time, it will lead to the excessive running current of the compressor, which will easily burn the motor and damage the valve plate of the compressor outlet.The reasons for the high-voltage fault found in the maintenance experience of refrigerator are as follows:(1) Refrigerator maintenance experience 1:The cooling water temperature is too high, and the condensation effect is not good. The rated working condition of cooling water required by water chillers is 30~35℃. The high water temperature and poor heat dissipation will inevitably lead to high condensation pressure, which often occurs in high temperature seasons. The causes of high water temperature may be: cooling tower failure, such as the fan is not turned on or even reversed, and the water distributor does not turn, which shows that the cooling water temperature is very high and rises rapidly; The outside temperature is high, the waterway is short, and the amount of water that can be circulated is small. In this case, the cooling water temperature is generally maintained at a high level, which can be solved by increasing the water storage tank.(2) Refrigerator maintenance experience II:The cooling water flow rate is insufficient, and the rated water flow rate cannot be reached. The main performance is that the pressure difference between the inlet and outlet of the unit becomes smaller (compared with the pressure difference at the beginning of the system operation) and the temperature difference becomes larger. The reason of insufficient water flow is that the system lacks water or has air. The solution is to install an exhaust valve at the height of the pipeline for exhaust. The pipeline filter is blocked or too fine, and the water permeability is limited. Appropriate filters should be selected and the filter screen should be cleaned regularly; The selection of water pump is small, which is not compatible with the system.(3) Refrigerator maintenance experience 3:Scaling or plugging of condenser. The condensate water is usually tap water, which is easy to scale when it is above 30℃. Moreover, because the cooling tower is open and directly exposed to the air, dust and foreign matter can easily enter the cooling water system, resulting in dirty blockage of the condenser, small heat exchange area and low efficiency, and also affecting the water flow. Its performance is that the pressure difference between the inlet and outlet water of the unit and the temperature difference become larger, the temperature of the condenser is very high when touched by hand, and the copper tube of the condenser is hot. The unit shall be backwashed regularly, and chemical cleaning and descaling shall be carried out when necessary.(4) Refrigerator maintenance experience 4:Too much refrigerant charge. This situation generally occurs after maintenance, which is characterized by high suction and discharge pressure, high equilibrium pressure and high compressor operating current. Under rated working conditions, air shall be discharged according to the suction and discharge pressure, balance pressure and operating current until it is normal.(5) Refrigerator maintenance experience 5:The refrigerant is mixed with non-condensable gases such as air and nitrogen. This kind of situation usually happens after maintenance, and the vacuum pumping is not complete. It can only be drained, re-vacuumed and refilled with refrigerant.(6) Refrigerator maintenance experience 6False alarm caused by electrical fault. Due to damp, poor contact or damage of the high-voltage protection relay, the electronic board of the unit is damp or damaged, and the communication fault causes false alarm. This kind of false fault is often that the HP fault indicator light on the electronic board is not lit or slightly lit, the manual reset of the high-voltage protection relay is invalid, the computer displays "HP RESET", or it disappears automatically, and the running current of the compressor is normal, and the suction and exhaust pressures are also normal.