Refrigeration unit fluorine system operation and commissioning instructions and experience summary version

Refrigeration unit fluorine system operation and commissioning instructions and experience summary version

1、 Pre operation inspection

Before running and debugging, it is necessary to conduct a pre operation inspection of the refrigeration system. The inspection content is as follows:

1. Check the electrical wiring to ensure that all wiring terminals are securely fastened, and ensure that the wiring is correct, its insulation performance, and system grounding meet the requirements.

2. Before starting, observe the oil level of the compressor, which should be in the center or slightly above the oil sight glass of the compressor

3. Check the dual pressure controller, temperature controller, defrosting time controller, oil pressure safety controller, and other safety control

devices, and adjust them if necessary.

4. Connect the refrigerant pipeline and inject the refrigerant to be used. Before injection, the weight of the refrigerant container should be weighed to ensure accurate and accurate refrigeration dosage of the injection system. If it is necessary to inject refrigerant into the system through the suction side of the compressor, it can only be injected in a gaseous state. Liquid refrigerant is injected into the high-pressure side of the compressor.

5. Observe the system pressure before and during the filling process. Do not add oil when the system refrigerant is insufficient, unless the oil level is extremely low. Continue to charge until the system has sufficient refrigerant to operate normally. Do not overfill, remember that bubbles on the mirror may be caused by fluid resistance or refrigerant shortage.

2、 Operation debugging inspection

1. Close the air switch used in the electrical control box. If only the indicator light of the phase sequence protector inside the box is not on, replace any two phases of the power supply to make the indicator light on.

2. Close the boat shaped switch on the electric control box door. At this time, the compressor should work and the refrigeration indicator light on the box door should be on. If there is no response, check the defrosting time controller to see if it is in the defrosting state. Check the dual pressure and temperature controls to see if their contacts are closed. Identify the cause and adjust these components to start the compressor.

3. If the compressor is running, it is necessary to verify whether the rotation of the vortex machine is correct. You can touch the exhaust pipe of the compressor by hand. If the exhaust pipe is hot, it indicates that the rotation is correct. If there is no change in temperature and the compressor noise is particularly loud, it indicates that the rotation of the compressor is incorrect. Simply adjust the two phases of the connecting cable between the electric control box and the compressor to change the rotation of the compressor. Attention: At this time, the phase sequence of the power supply line in the electronic control box cannot be adjusted.

4. After the compressor runs stably, measure the compressor circuit current with a multimeter to see if it matches the current value at the evaporation temperature on the unit parameter table. If the difference is significant, you can check the power supply voltage, condenser heat dissipation, refrigerant charging amount, etc., identify the cause, and then set the setting value of the motor protection air switch in the electrical control box to 1.2 times the rated current value in this state.

5. Connect the system to a dual pressure gauge and verify the set value of the dual pressure controller. For the high voltage protection value, in the R22 system:

Reference for air-cooled units: 350psig (25kg/cm2);

The water unit is for reference: 300 psig (approximately 22 kg/cm2).

6. If the compressor can start but the overload protector always trips, it may be caused by the following reasons:

A. Dirty condenser or air inside the condenser;

B. Insufficient refrigerant filling or system leakage;

C. The condensation fan is not working properly;

D. The voltage and current of the compressor are abnormal.

If all the above situations are normal, then the transformer protector may be broken and should be replaced. If the operation is normal and the compressor overheats for an unknown reason, or if the current exceeds the normal range and is sufficient to continuously activate the protector, then the compressor is damaged internally and should be replaced.

7. After the system operates without any faults for at least two hours under normal conditions, it can be manually forced to defrost once to measure whether the defrosting current is normal. Otherwise, check the corresponding circuit and heating tube to ensure normal operation. At the same time, check whether the drainage is unobstructed and whether the sealing of the drainage pipe is good. Then, it can operate under automatic control conditions for a whole day.

8. Check the exhaust and suction pressures of the compressor cylinder, if they are not within the system design range, identify the cause and take corrective measures.

9. Check the operation of the liquid pipe sight glass and expansion valve. If there are signs that more refrigerant is needed, perform a leak check on all connections and system components, and repair any leaks before adding refrigerant.

10. Observe the oil level in the compressor crankcase, and if necessary, add oil to the center of the sight glass.

11. Check the superheat setting value of the thermal expansion valve. The temperature bulb must be in full contact with the suction pipe. If the superheat setting of the valve is too low, it will cause a decrease in refrigeration capacity, refrigerant liquid reflux, and damage to the compressor bearings. It is necessary to prevent liquid refrigerant from flowing into the compressor.

12. Carefully check the voltage and current values at the compressor terminals using a multimeter. The voltage error must be limited to plus or minus 10% of the specified value on the compressor nameplate. [Source: Refrigeration Encyclopedia]. The normal current should not exceed 120% of the rated current. If there is excessive current, the cause should be immediately identified and corrective measures taken. On a three-phase electric compressor, check if the load of each phase is balanced, and the imbalance of the three-phase voltage should not exceed 3%.

13. All fans used in air-cooled condensers, evaporators, etc. should be checked for correct rotation direction. Check the installation of the fan for tightness and alignment.

14. Check the defrost starting and ending points of the defrost controller, and measure the defrost duration. If a heater is used in the crankcase, check the heater.

15. Check the pressure setting value of the winter condensation pressure controller. Check if the setting value of the crankcase pressure regulating valve is appropriate.

16. Adjust the water valve of the water cooling system to maintain the required condensation temperature and check if the water pump is operating properly.

17. Do not let the device operate unattended when the entire system is not in normal operation and the oil level is not maintained in the center of the mirror.