Maintenance Methods for Refrigerant Leak in Air - conditioner Outdoor Unit

I. Refrigerant Leakage in the Pipes Inside the Outdoor Unit

1. Measurement of System Operating Pressure
   Turn on the air conditioner in the remote - controlled cooling mode. Both the outdoor fan and the compressor start to operate. However, the air blown from the indoor unit is close to natural wind. When touching the evaporator, only one grid is cool and frosted, and most of it is at room temperature.

   

   

   
   Go to the outdoor unit for inspection. Visually, the two - way valve is frosted, and the three - way valve is dry. Connect a pressure gauge to the service port of the three - way valve. The system operating pressure is only 0.15MPa, indicating that the system lacks refrigerant.
2. Inspection of Leak Points
   Turn off the power supply of the air conditioner. Check that the system static pressure is about 0.8MPa, which can be used for leak detection. First, use foam to check the interfaces at the two - way valve and three - way valve of the outdoor unit. After a long - time observation, no bubbles are seen. Then go to the indoor unit, peel off the wrapping tape, and check the interfaces of the thick and thin pipes. After a long - time observation, no bubbles are seen either. This indicates that the interfaces of both the indoor and outdoor units are normal. Use a wrench to tighten the interfaces of the indoor and outdoor units. After turning on the machine again and adding refrigerant to the normal pressure of 0.45MPa, the cooling function returns to normal.
3. Inspection of the Pipes Inside the Outdoor Unit
   About 5 days after the user used the air conditioner, they reported again that it was not cooling. When going for on - site inspection, the system operating pressure dropped to about 0.1MPa again, indicating that there is a refrigerant leakage fault in the refrigeration system. Since the outdoor unit vibrates greatly and has a relatively high failure rate. Remove the top cover and front cover of the outdoor unit. Observe that there are obvious oil marks on the system pipes, indicating that the leak point is in the pipes of the outdoor unit. When using foam for inspection, it is found that the leak point is a crack in the suction pipe of the compressor. The reason is that the suction pipe of the compressor is too close to the connecting pipe of the four - way valve and they collide. When the compressor operates, due to vibration, they rub against each other, causing the pipe wall to become thinner and finally crack, resulting in a refrigerant leakage fault.
   Maintenance Measures: Empty the refrigerant in the refrigeration system. Use a welding torch to repair the welds of the suction pipe of the compressor and the connecting pipe of the four - way valve. Then use the top - empty method to remove the air in the system. Check that there are no leak points at the welded parts. After turning on the machine again and adding refrigerant to 0.45MPa, the cooling function returns to normal. Both the two - way valve and three - way valve of the outdoor unit are dewy.

II. There are Porosities in the Welds of the Extended Connecting Pipes

1. Extended Connecting Pipes
   Unwrap the wrapping tape, find the connection part of the original machine pipes and the extended pipes. Observe that there are obvious oil marks on the thick pipe in the connecting pipes. It is preliminarily judged that the leak point is the weld between the original machine pipe and the extended pipe.
2. Refrigerant Leakage at the Weld of the Thick Pipe
   Apply detergent foam to the weld of the pipe. Check that no bubbles come out from the weld of the thin pipe, but bubbles come out from the weld of the thick pipe, indicating that the refrigerant leakage part is the weld of the thick pipe.
   Wipe off the foam on the weld. Carefully check the weld of the thick pipe and find a porosity. This indicates that the installer did not weld the weld well when extending the connecting pipe. The porosity causes the system to leak refrigerant, resulting in the fault of poor cooling effect.
3. Flaring and Welding the Weld of the Thick Pipe
   Turn on the machine again by remote control. After the compressor runs, close the valve core of the two - way valve. When the system pressure becomes negative, quickly close the valve core of the three - way valve to recover the refrigerant in the evaporator and the connecting pipes into the condenser.
   Use a cutter to cut off the weld of the thick pipe with porosity, flare it again, and weld it with a welding torch. Use the refrigerant in the condenser to remove the air. Open the valve cores of the two - way valve and three - way valve. Apply detergent foam to the weld of the thick pipe again. Check that no bubbles come out, indicating that the weld of the thick pipe no longer leaks refrigerant.
   Maintenance Measures: Re - flare and weld the weld of the thick pipe. After turning on the machine for cooling, add refrigerant R22 to the system until the pressure reaches 0.45MPa, and the cooling function returns to normal.

Summary