1. Check the main circuit first. Such as whether there is electricity in the power supply, whether the voltage is normal, whether the fuse has been burned due to starting overload, whether the air switch trips, whether the switch contacts are good, whether the power supply is out of phase. When starting, observe the voltmeter and ammeter. When the water cooler is not equipped with ammeter and voltmeter, the multimeter or pen can be used to check the situation of the power supply. When the voltage of the power supply is too low, the compressor can not start.
2. For piston refrigeration compressor, does the connecting rod big head bearing bush and crankshaft hold the shaft? These can be caused by excessive exhaust temperature or coking of lubricating oil, which causes the cylinder to bond with piston and prevents the compressor from starting.
3. Check differential relays and high and low voltage relays. When the oil pressure of the compressor is abnormal, the compressor can be stopped running. At the same time, when the exhaust pressure and suction pressure of the compressor are abnormal, the compressor can not start or will stop running soon after starting.
4. Check whether the amount of frozen water, cooling water and water temperature are normal. If the water volume is small and the water temperature is high, the condensation pressure will rise sharply and the evaporation temperature will drop rapidly. Owing to the action of the unit protection facilities, the unit will often shut down quickly.
5. Check whether the relevant solenoid valves and control valves are malfunctioning and whether they are opened or closed as required.
6. Check whether there is any leakage of working substance in the induction temperature package of the temperature relay, or the wrong adjustment.