1. In the measurement of the pressure, the first thing to do is to check the pressure gauge high and low pressure manual valves and fast connection valve is closed. 2. The high and low pressure gauge group and the automobile air conditioning system is properly connected (blue low-pressure quick-connect valve and low-pressure maintenance valve connection, red high-pressure quick-connect valve and high-pressure maintenance valve connection), and open the valve.
3. Turn on the car engine so that it runs at idle, connected to the air conditioning system for 10min, you can read the table group pressure, under normal circumstances, the high pressure value should be between 1.3 ~ 1.5MPa, the highest not more than 1.7MPa, the low-pressure value should be between 0.1 ~ 0.25MPa, the highest not more than 0 AMPa. will be read between the high and low pressure values and standard values. Comparison, combined with other symptoms of the system, you can determine the system failure. Second, evacuate the refrigerant
Before removing any part of the system, the refrigerant inside the system should be evacuated, and pay attention to the evacuation of the refrigerant should be discharged outside, not indoors, so as not to contaminate the working environment. The operation procedure is as follows:
1. Place the center yellow hose in a graduated container to hold the refrigerant oil discharged from the system. 2. Slowly open the low-pressure manual valve, so that the refrigerant from the low-pressure side of the slow flow, pay attention to not too fast, otherwise a large number of refrigeration oil will be discharged with the refrigerant.
3. When the low pressure drops to a certain value, and then slowly open the high-pressure manual valve, so that the refrigerant from the high and low-pressure side at the same time. 4. When the high and low pressure values drop to a relatively low value at the same time, open the high and low pressure manual valve all the way so that the refrigerant is discharged. When the value of the two tables are down to 0, indicating that the refrigerant has been completely emptied, close the high and low pressure manual valve. 5. Take out the container, the amount of lubricant in the container is the amount of lubricant that needs to be added to the system.
6. Cooling system has been released after the refrigerant, it can be leak detection or disassembled for repair. Be careful to prevent dust or other impurities into the system, the hoses and openings should be covered. Third, the system leak detection
There are a variety of methods for leak detection of refrigeration systems, such as visual leak detection, soapy water leak detection, nitrogen water leak detection, fluorescent leak detection, electronic leak detection, gas pressure leak detection and halogen lamp leak detection, etc., the following is mainly introduced to the soapy water leak detection.
1. The middle yellow hose of the high and low pressure gauge group is connected to the vacuum pump's pumping port. In order to prevent a large amount of air from gathering in the gauge group to produce the danger of bursting the gauge, open the high and low pressure manual valves, and then turn on the pump switch to make the air enter the system smoothly. 2. When the pressure on the high pressure side reaches 0.7 ~ 0.8MPa, close the pumping system (first close the pump switch, then close the high and low pressure manual valves).
3. With a sponge dipped in soapy water evenly coated around the pipe, if there are bubbles, indicating that there is a leak. Generally prone to leakage parts of the pipeline interface, replace the same type of seal can be.
4. Repeat steps 1 and 2, leak detection again, 10min after observation, if the pressure value is unchanged, that the system has been sealed, you can carry out the next operation; if the pressure value drops, that the system is still leaking, need to continue to leak detection and repair. Fourth, vacuum
The so-called vacuum, is to make the system in the form of air and moisture in the gas is pumped out to prevent the system to produce ice blocking or poor heat dissipation failure. Note that the evacuation must be carried out at least 45min, otherwise the water inside the system is not clean, in the process of evacuation, the lubricant in the system will not be pumped out. Specific operations are as follows:
1. Connect the middle yellow hose to the vacuum port, open the vacuum pump switch, and then open the high and low pressure manual valves, so that the air and moisture in the system in the form of gas is pumped out.
2. When the low-pressure side pressure reaches 93kPa, close the vacuum system (first close the high and low-pressure manual valves, and then close the vacuum pump to prevent air and moisture from entering the system), and then carry out the vacuum holding pressure. 20min later, if the low-pressure value is unchanged, it means that the system seals well, if the low-pressure value rises, it means that the system is still leaking, and then it should be continued to the previous leakage check and repair, and it can't be carried out in the next step. operation. 3. If the system seals well, then continue to repeat step 1, a few minutes from the high-pressure side of the refrigeration oil can be added, pay attention to the refrigerant according to the evacuation of the refrigerant when the amount of refrigeration oil in the container to be added, if the system replaces a certain part, but also the amount of refrigeration oil in the component to be supplemented, and to add the same type of refrigeration oil grade. Specific operation is the first to close the high-pressure manual valve, the red high-pressure hose from the table group to pull down, quickly inserted into the bottle of refrigerant oil, a few seconds after the absorption is complete, then quickly screw the red high-pressure tube into the table group, open the high-pressure manual valve to continue to vacuum until the low-pressure value of the state of negative pressure.
4. Finally close the vacuuming system (first close the high and low pressure manual valve, and then close the vacuuming switch). Vacuum, automotive air conditioning system inside a large vacuum, which can rely on the vacuum suction from the high-pressure side of the rapid charging refrigerant. With the refrigerant into the system inside, the vacuum is getting smaller and smaller, not enough to rely on the system's own vacuum suction will be refrigerant into the system, this time from the low-pressure side of the remaining refrigerant to add. 1. Refill from the high-pressure side
(1) first counterclockwise rotation of the refrigerant charging valve handle, so that the needle valve is completely retracted; and then clockwise rotation of the plate nut, so that it is connected to the top of the tank threaded connection, and the two are connected as one.
(2) Connect the center yellow hose to the refrigerant charging valve, then tighten the upper handle clockwise so that the thimble pierces the mouth of the refrigerant bottle.
(3) The center yellow hose needs to be evacuated because air has entered it. Steps are: loosen the refrigerant charging valve counterclockwise upper handle, loosen the yellow hose and the table set of interfaces, so that the refrigerant from the middle of the yellow hose overflow, when you see a white mist sprayed out and hear the "Pu" sound, that the air has been emptied, then quickly tighten the yellow hose and the table set of interfaces.
(4) open the high-pressure manual valve, inverted refrigerant tank, so that the refrigerant in the form of liquid flow into the refrigeration system, when you see the refrigerant tank on the frost slowly faded, indicating that the refrigerant has been added.
(5) Close the high-pressure manual valve first, and then remove the refrigerant can from the charging valve.
(6) Special attention should be paid to the fact that the engine can not be started when the refrigerant is refilled from the high-pressure side, if the engine is started and the air conditioner is turned on, after the compressor is running, the pressure of the refrigeration system will be greater than that in the refrigerant tank, resulting in the impossibility of continuing to refill the refrigerant tank, and if the excessive pressure enters the instrument low-pressure gauge or flows backward into the refrigerant tank, it will result in a serious safety accident. Do not unscrew the low-pressure manual valve for the whole process, and only one bottle of refrigerant can be added from the high-pressure side, and gloves should be worn to prevent your hands from being frostbitten. 2. Add from the low-pressure side
(1) First of all, screw the refrigerant charging valve clockwise into the mouth of a new bottle of refrigerant, so that the two are connected as a whole, and then tighten the upper handle clockwise, so that the thimble to pierce the mouth of the refrigerant bottle. (2) Exhaust the air inside the center yellow hose.
(3) Start the engine, turn on the air conditioning switch, set the blower to the maximum airflow position, and set the cooling and heating switch to the position of maximum cooling.
(4) the low-pressure manual valve open, is taking the refrigerant tank, never inverted and do not violently shake (otherwise prone to liquid shock hazards), so that the refrigerant in the form of gas inhaled into the refrigeration system, when you see the refrigerant tank on the frost slowly faded, indicating that the refrigerant has been added.
(5) Close the low-pressure manual valve, then remove the refrigerant tank from the charging valve and replace it with a new bottle of refrigerant.
(6) When adding to the last bottle of refrigerant, always pay attention to the flow of refrigerant in the liquid-viewing mirror, when you see a large number of bubbles that the refrigerant is not enough, you should continue to add, when you see fewer and fewer bubbles, and finally only one or two bubbles left. Finally only one or two bubbles left, and then look at the value of the high and low pressure gauge, if it reaches the standard value, indicating that the refrigerant has been added to the right, this time to hurry to close the low-pressure manual valve, shut down the engine.
(7) The refrigerant charging valve upper handle clockwise tightened, and then pull out the center yellow hose. At this point, point the refrigerant bottle at the ground (be careful not to point it at yourself and others to avoid frostbite), loosen the upper handle of the charging valve counterclockwise so that the refrigerant gas is sprayed out, and when there is no gas sprayed out, the charging valve can be removed from the refrigerant tank only.
(8) The high and low pressure hoses of the pressure gauge group are pulled out of the air conditioning system, and the protective cover of the high and low pressure service valves are covered. V. Charge refrigerant
First of all, it should be charged with the appropriate amount of refrigerant of the specified model according to the requirements of the accident car, and secondly, the refrigerant charge should be divided into two methods: charging from the high-pressure side and adding from the low-pressure side. Just pumped six, notes
1. Measure the system pressure, you must close the high and low pressure manual valves, otherwise not only can not measure the pressure, but also make the system refrigerant flow out of the system.
2. When emptying the refrigerant, be sure to slowly open the high and low pressure manual valves to prevent a large amount of refrigeration oil outflow, resulting in waste. 3. Leak detection with soapy water, to the system of various pipelines, especially the pipeline interface check in place, the whole process sometimes lasts several hours, be patient.
4. Vacuum time should be at least 45min, not too short.
5. When charging refrigerant from the high pressure side, remember not to open the engine, the refrigerant bottle should be inverted, and only one bottle can be refilled. From the low-pressure side to add refrigerant, be sure to open the engine, the refrigerant bottle should be placed, not inverted or shaking violently.