Common faults and solutions of screw chillers-Shenzhen Oukelong Technology Industrial Co., Ltd

Common faults and solutions of screw chillers

1. High voltage malfunction
The compressor exhaust pressure is too high, causing the high-pressure maintenance relay to operate. The discharge pressure of the compressor reflects the condensation pressure, and the normal value should be 1. 4~1. 6MPa, maintenance value set to 2. 0MPa. If the pressure is too high for a long time, it will cause excessive operating current of the compressor, which can easily burn the motor and damage the compressor exhaust valve plate. The reasons for high voltage problems are as follows:
(1) The cooling water temperature is too high and the condensation effect is poor. The rated operating condition of the cooling water required by the chiller unit is between 30~35 ℃. High water temperature and poor heat dissipation will inevitably lead to high condensation pressure, which often occurs during high temperature periods. The reason for the high water temperature can be: problems with the cooling tower, such as the fan not turning on or even reversing, the water distributor not turning, manifested as high and rapidly rising cooling water temperature; The external temperature is high, the waterway is short, and the amount of recyclable water is small. In this situation, the cooling water temperature is usually maintained at a high level, and the solution can be to increase the water storage tank.
(2) The cooling water flow rate is insufficient and cannot reach the rated water flow rate. The main manifestation is that the pressure difference between the inlet and outlet of the unit decreases (compared to the pressure difference at the beginning of the system's operation), and the temperature difference increases. The reason for insufficient water flow is the lack of water or air in the system. The solution is to install an exhaust valve at a high point in the pipeline for exhaust; If the pipeline filter is blocked or too fine, and the permeability is limited, a suitable filter should be selected and the filter screen should be cleaned regularly; The water pump selection is relatively small and not compatible with the system.
(3) The condenser is scaled or blocked. Tap water is commonly used for condensate water, which easily forms scale at temperatures above 30 ℃. As the cooling tower is open and directly exposed to the air, dust and foreign objects can easily enter the cooling water system, causing blockages in the condenser, small heat exchange area, low efficiency, and affecting water flow rate. Its manifestation is that the pressure and temperature difference between the inlet and outlet water of the unit increase, and the temperature of the condenser is very high when touched by hand, causing the outlet copper pipe of the condenser to be hot. Regularly backwash the unit and perform chemical cleaning and descaling if necessary.
(4) Excessive refrigerant charging. This situation usually occurs after repair, manifested as high suction and exhaust pressure, balance pressure, and high compressor operating current. The air should be released according to the suction and exhaust pressure, equilibrium pressure, and operating current under rated operating conditions until normal.
(5) The refrigerant contains non condensable gases such as air and nitrogen. This situation usually occurs after repair when the vacuum is not completely evacuated. It can only be drained, vacuumed from the beginning, and filled with refrigerant from the beginning.
(6) False alarms caused by electrical problems. Due to dampness, poor contact or damage of high-voltage maintenance relays, dampness or damage of unit electronic boards, and communication problems, false alarms may occur. This kind of fake problem often causes the HP malfunction indicator light on the electronic board to not light up or light up slightly, the manual reset of the high-voltage maintenance relay to be ineffective, the computer to display "HPRESET" or disappear automatically, and the compressor operating current and suction and exhaust pressure to be normal.

Common faults and solutions of screw chillers

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