Next, we will know what inspections need to be done before the next screw chiller is started? (II)
2： Inspection of compressor and refrigerant pipeline system
1. Check whether the oil level in the compressor is normal. The normal compressor oil level is generally in the middle of the mirror.
2. Check whether the volume regulating solenoid valve coil of the compressor is locked and whether the volume regulating capillary tube is damaged.
3. All refrigerant valves in the refrigeration system (corner valve at the outlet of the condenser, suction and discharge stop valves of the compressor) are open to make the refrigerant system smooth.
4. Check whether the high and low pressure values and the high and low pressure setting values of the pressure relay are normal (the high pressure setting value is 1.8MPa, and the low pressure setting value is 0.2MPa, and the user shall not change them without authorization).
5. Check whether the compressor lubricating oil is preheated for more than 8 hours. Before the test run, the oil heater shall be powered on and heated for at least 8 hours to prevent foaming of the refrigerant oil during startup. If the ambient temperature is low, the oil heating time needs to be relatively longer. When starting at low temperature, due to the high viscosity of lubricating oil, it will be difficult to start and the compressor will not be loaded or unloaded properly. Generally, the minimum lubricating oil temperature shall be above 23 ℃ before operation.
6. Check whether the compressor wiring is correct. Shut down the compressor immediately after startup, observe the change of instantaneous system pressure to ensure that the exhaust pressure rises and the return pressure drops. On the contrary, the compressor is in reverse direction, and the wiring sequence of the compressor needs to be readjusted.
7. Conduct test run when the main circuit is disconnected, and check whether the action sequence is normal. The normal starting sequence is: turn on the power supply, press the unit start key three minutes later, the star AC contactor pulls in, after a short time, the star AC contactor disconnects, the triangle AC contactor pulls in, and the unit starts with the starting load value and gradually loads.