Cold room commissioning involves assembling and installing the prefabricated components, connecting the refrigeration units, and integrating temperature control system.
Measure the power supply
Measure the resistance of the compressor and the insulation of the motor
Fill refrigerant
After vacuum, fill refrigerant into the liquid storage tank roughly 70-80% of the standard filling volume and then run the compressor at low pressure to fill the refrigerant into standard volume, finally set the temperature and opening state of the expansion valve according to the frosting and the cold storage condition.
Pay attention to abnormal sounds
After starting the machine, first listen to whether the compressor sound is normal, check whether the condenser and evaporator are running normally and whether the compressor current is stable.
After stable cooling, check the refrigeration system all parts performance: exhaust pressure, suction pressure, exhaust temperature, suction temperature, motor temperature, crankcase temperature, expansion valve temperature, observe the frosting of the evaporator & expansion valve, and observe the oil level and if the equipment’ sound is abnormal
Clean refrigeration system
The inside of the refrigeration system must be very clean, otherwise it will block the throttle holes and the lubricating oil paths.
For ammonia system: Usually use refrigeration compressor to boost the system air, and rapidly flush out the air at the lowest level of each main container (such as condenser, evaporator, liquid storage tank), so that the garbage is discharged from the system.
Test Run Attention
Check valve condition
Check whether each valve is in the open state, especially the exhaust shut-off valve, please don’t close it.
Open the cooling water valve of the condenser. For an air-cooled condenser: turn on the fan, check the diversion.
Remember the water & air volume should meet the requirements.
Check electrical control
Should test the electrical control circuit separately in advance and ensure the power supply voltage is normal before running.
Keep the oil level of compressor crankcase in a normal position (generally keep it at the horizontal centerline of the sight glass).
Check pressure value
Check whether the indicated values of high & low pressure gauges are within the normal operating pressure range of the compressor.
Check the oil pressure gauge value:
For a compressor with an energy unloading device: Oil pressure value should be 0.15-0.3MPa higher than the suction pressure.
For a compressor without an energy unloading device: Oil pressure value should be 0.05-0.15MPa higher than the suction pressure. Otherwise, should adjust the oil pressure.
Check refrigerant flow
Listen to the expansion valve if has a refrigerant flowing sound, and observe whether there is normal condensation (air conditioner) and frost (cold storage) in the expansion valve pipeline.
Compressors with energy unloading should work at full load at the beginning of the operation. You can judge by sensing the temperature of the cylinder head by hand.
