What are the reasons for the refrigeration compressor failing to start or stopping soon after starting?

1) First, inspect the main circuit. Check if the power supply is live, if the voltage is normal, if the fuse has been blown due to overload during startup, if the air switch has tripped, if the switch contacts are in good condition, and if the power supply is phase-deficient. During startup, observe the voltmeter and ammeter. If small refrigeration and air conditioning equipment do not have an ammeter or wattmeter installed, a multimeter or test pen can be used to check the power supply condition. If the power supply voltage is too low, the compressor may not start.

2) Check the differential pressure relay and the high and low pressure relays. When the compressor oil pressure is abnormal (exceeding a certain value or falling below a certain value), it can stop the compressor from running. At the same time, when the compressor's discharge pressure (high pressure) and suction pressure (low pressure) are abnormal, the compressor cannot be started or will quickly stop running after being started.

3) Check whether the amount of chilled water, cooling water, and water temperature are normal. If the water amount is small and the water temperature is high, it will cause a sharp increase in condensing pressure and a rapid decrease in evaporation temperature. Due to the action of the unit's protective facilities, it often shuts down quickly.

4) The working medium inside the temperature sensing bulb of the temperature relay has leaked, or the adjustment is incorrect.

5) For piston refrigeration compressors, it is important to check whether the connecting rod big end bearing shell and the crank sleeve are seized together. These issues may arise during previous operation due to high exhaust temperature, or they may be caused by the coking of lubricating oil, which leads to the sticking of the cylinder and piston, making the compressor unable to start.

6) Check whether the relevant solenoid valves and regulating valves are malfunctioning, and whether they are opened or closed as required.

        The above reasons often cause the refrigeration compressor to fail to start, or to quickly shut down after just a few minutes or ten minutes of starting. Careful investigation of the causes is necessary, and the equipment should not be forcibly restarted until the cause has been identified, to avoid damage to the equipment.