1. Check before operation
The inspection before the start-up of the refrigeration equipment is a key link related to the normal operation of the refrigeration equipment, so the operation and maintenance personnel should be particularly careful when inspecting:
1. Whether the power supply is within the range of 380V±5%.
2. Whether the power supply and control switch is in the closing position.
3. Whether the button switch and the indicator light on the panel of the electric control cabinet are in good condition and whether the indication is normal or not.
4. Whether the controller display is normal, and whether there is a fault display barcode or text.
5. Whether the oil level of the refrigerating unit is at 1/2 of the oil indicating mirror, and what is the color of the oil.
6. Whether the oil temperature of the refrigeration unit is within the normal temperature range.
7. Whether the high and low pressures of the refrigeration unit are balanced.
8. Whether there is any leakage in the refrigeration unit and the system.
9. Check whether the valves on the refrigeration unit and refrigeration system, including the cooling water system, are fully opened.
10. Whether the liquid supply solenoid valve works normally.
11. Is there any abnormal noise in the coil of the evaporator system?
12. Is there oil bloom in the condensed water of the evaporator?
13. Is there any abnormal sound when the evaporator fan is started manually?
14. Is the direction of the evaporator fan normal?
15. Check whether the control panel and sensors of the refrigeration unit are in good condition.
16. Confirm whether the setting data of the refrigeration unit control panel are correct.
17. View the historical fault records of the user menu.
18. Check that there is no fault prompt on the display of the control panel.
19. The compressor motor can be jogged first to see if it can be started, and whether there are faults such as excessive starting current.
20. Determine whether the direction of rotation of the refrigeration compressor is correct. It is particularly important that the compressor cannot be reversed.
2. Inspection of refrigeration auxiliary equipment
The pre-start inspection of refrigeration auxiliary equipment is an important part related to the long-term normal operation of refrigeration equipment, so the operation and maintenance personnel must be particularly careful and careful inspection:
1. Check whether there is water leakage in the cooling tower pool.
2. Is there any water in the pool of the cooling tower? Is the water level normal?
3. Whether the water distributor of the cooling tower is broken or falls off.
4. Whether the water quality of the cooling tower is normal.
5. Is there any abnormal sound when the cooling tower fan is started manually?
6. Whether the direction of cooling tower fan is correct.
7. Whether the running current of cooling tower fan is normal.
8. Whether there is water leakage at the packing of the cooling water pump, and whether the valves are open.
9. Is there any abnormal sound when the cooling water pump is started manually?
10. Whether the direction of cooling water pump is correct.
11. Check whether the running current of the cooling water pump is normal.
12. Whether the instrument of the cooling water pump system is damaged.
13. Is there any water leakage in the cooling water pump system?
14. If it is an air-cooled condenser, check the steering, speed, current and voltage of the air-cooled condenser.
3. Turn on the refrigeration equipment
Before the official start-up, please confirm the above contents:
1. Press the start compressor button, and the cooling water pump will start running at this time, please check whether the operating voltage and starting current of the cooling water pump are normal, and then check whether the inlet and outlet pressure of the cooling water pump is normal. Source of this article: Refrigeration Encyclopedia. Whether the liquid supply solenoid valve is open or not, the R22 liquid is supplied to the evaporator in the system through the thermal expansion valve. After a few seconds, the suction pressure rises to a certain value, and the compressor will make a movement sound. The starting current is twice the rated current of the motor, and it is converted to the rated current of the normal compressor motor in an instant.
2. When the compressor is running normally, the compressor oil heater will stop running, and the indicator light of the electric heater will go out.
3. When the compressor is running, the coil or cooling fan in the warehouse will start to run and start to cool down.
4. When the cooling water temperature reaches 25°C, Refrigeration Encyclopedia prompts: Look at the set temperature here, and the cooling tower fan will automatically start running, forcing air convection to reduce the temperature of the cooling water. At this time, the operator needs to determine the operating voltage of the fan , whether the running current and fan running sound are normal.
5. When the compressor is fully running, it is necessary to confirm the operating voltage, operating current, and compressor operating sound. Tips from Refrigeration Encyclopedia: At the beginning, the fully automatic unit runs a compressor. When the cooling capacity of the compressor cannot meet the external energy, the CPU will issue an instruction to start the second compressor to achieve the purpose of dual-machine operation.
6. If the machine is a double-head refrigeration compressor unit, one compressor is started at the beginning of operation. When the temperature sensor on the computer board detects that the temperature curve is not driven by cooling, the computer will drive the second compressor. Start running. When the temperature of the refrigeration system reaches the set requirement, the CPU will unload a compressor to run, and when the temperature of the warehouse fully reaches the set temperature, the CPU will order the first compressor to stop working and put it in a standby state. When the second operating temperature is higher than the set temperature of the room, the CPU starts the first compressor to start working.
7. After the compressor system is in normal operation, the operator needs to confirm the discharge pressure, discharge temperature, return air pressure, return air temperature, compressor oil pressure, oil temperature, and oil level of the compressor. The position should not be lower than 1/3 of the oil cup), the oil color, the water inlet temperature of the condenser, and the water outlet temperature of the condenser. The above technical indicators must be within the normal range of compressor operation.
8. After the compressor has been running for a period of time, observe the cooling rate of the warehouse temperature. The fast cooling speed of the warehouse indicates that the cooling capacity of the refrigeration compressor is large, and the fan stirs the airflow more fully in the warehouse. In addition, check whether there is any vibration in the coil box, whether there is any abnormal sound from the air cooler, whether the direction of the fan is correct, and whether there is any backwater phenomenon in the condensate pipe.
9. When the temperature of the warehouse is close to the set value and the refrigeration compressor is running at full load, check the evaporation temperature of the system, the outlet air temperature of the fan coil unit, and the liquid flow of the liquid supply mirror.
10. When the refrigeration compressor cools down the warehouse, when the operating cycle of the compressor changes from one cycle to another, the operator needs to determine the cycle time of the compressor on and off, and it is best to record it.
