The compressor is one of the four major components of the air conditioner and is also the heart of it. After long-term operation, it is prone to failure. If there is a problem with the air conditioner compressor, how to replace it? The following will talk about the method of replacing an AC compressor through 10 steps.
1.1 Turn off the Power and Unplug
Before replacing the compressor, be sure to cut off the power supply of the air conditioner and do not replace it with power on. Otherwise there is a risk of electric shock.
1.2 Release the Refrigerant in the Refrigeration System
Generally, the refrigerant is released from the needle valve of the three-way valve (low-pressure valve). First, use an Allen wrench to fully open the two valves of the outdoor unit. Connect one end of the hose to the three-way needle valve and the other end to the pressure gauge. Control the refrigerant discharge speed by adjusting the pressure gauge valve opening.
Due to the reduction in pressure and temperature of the refrigerant during the discharge process, wear gloves and control the refrigerant discharge speed during operation to avoid frostbite. If there is professional refrigerant recovery equipment, the refrigerant needs to be recovered to protect the environment.
1.3 Unscrew the Outdoor Chassis Covers
Generally, remove the top cover first, then remove the panel and side covers to expose the entire compressor. Then remove the wiring cover of the compressor.
When removing the compressor power cord, remember the connection condition between the compressor wires of different colors and the compressor terminals for reconnecting the wires correctly after replacing the compressor.
1.4 Remove the Discharge and Return Gas Connection Pipes
Before starting the hot work, make sure that the refrigerant in the pipeline has been discharged completely, especially for units with flammable refrigerants. Otherwise there may be a risk of combustion or explosion during the welding process of removing the discharge and return gas pipes.
For units with flammable refrigerants, perform the hot work in strict accordance with the manufacturer's requirements or return the compressor to the manufacturer for replacement.
1.5 Replace with a New Compressor
First, check whether the power supply and refrigerant type used by the new compressor are correct. If the compressor is of different models, it is also necessary to confirm whether the size of the starting capacitor used is consistent. If not, the capacitor needs to be replaced.
Confirm whether the rubber plugs of the discharge and return gas ports of the new compressor are in good condition, and whether the wiring box cover is intact and there are no cracks. During installing the compressor, try not to tilt it or the tilt angle should not exceed 45°.
After unplugging the plugs of the compressor discharge and return gas ports, try to complete the pipeline welding within 10 minutes. During the welding process, it is necessary to fill the pipe with nitrogen to prevent oxidation. The outside of the pipe should be well protected to prevent the welding torch flame from burning the surrounding parts. Or operate according to the requirements of the compressor specification to prevent impurities and moisture from entering the system and affecting the refrigerant system.
1.6 Wire the Compressor
Wire the compressor in the following way. Generally, there are three terminals on the compressor, and the symbols are generally C, R, and S.
According to the form of the compressor protector, the following two wiring methods are usually used:
1.7 System Leak Detection
After the compressor is installed, it needs to do the pressure holding and leak detection. Fill dry nitrogen into the refrigeration system from the previous refrigerant discharge port. Before holding the pressure, a pressure detection instrument should be connected to the system leak detection pipeline and the gas cylinder should be connected according to safety requirements. Use soapy water to check the weld for leaks and observe whether there are bubbles, or use a professional leak detection instrument for leak detection.
Make sure that the system has no leaks. If the system is large, it is recommended to hold the pressure for a certain period of time, observe whether the pressure has obvious attenuation, and then determine whether the system has leaks.
1.8 Vacuum the System
Before filling the refrigerant, the refrigeration system must be vacuumed. Before vacuuming, check again whether all valves are open. Connect the vacuum pump pipeline and the pressure gauge, and turn on the vacuum pump to remove the residual gas and moisture in the refrigeration system.
1. Before vacuuming, first discharge the gas used for leak detection in the refrigeration system, observe the pressure gauge, and when the pointer points to 0MPa, it means that the gas has been released.
2. Turn on the vacuum pump and observe the pressure value of the vacuum gauge. If the pointer points to -0.1MPa and keeps for a while, close the pressure gauge valve and turn off the vacuum pump.
Observe whether the pointer of the vacuum gauge rebounds. If it rebounds, it means that the vacuum degree cannot be maintained. Observe the vacuum gauge again after re-evacuating. If the pointer of the vacuum gauge rebounds after the second vacuuming, it means that there is a leak in the refrigeration system. The system needs to be re-checked and welded until there is no rebound.
1.9 Fill Refrigerant
The total filling amount of refrigerant is calculated based on the weight marked on the product nameplate and the length of the extended connecting pipe.
When filling, place the refrigerant bottle on the electronic scale, fill the system with liquid refrigerant, and observe the readings of the electronic scale at all times until the required filling amount is reached. If the filling amount does not meet the required, but the refrigerant cannot be filled into the system, then it is necessary to start the compressor and fill it into the system in the form of gaseous state until the required filling amount is reached.
If conditions permit, use an automatic refrigerant filling machine for filling. During the operation of the compressor, be careful not to directly fill the refrigerant in liquid form into the gas intake port, which may cause liquid slugging problems in the compressor and damage it. During the filling process, control the valve opening and observe the state of the refrigerant through the sight glass.
1.10 Start and Test the AC
Check the circuit system again, including whether various sensors are installed in place, connect the machine power supply, and ensure that the air conditioner is grounded normally.
Generally, turn on the air supply mode of the air conditioner first. After running for 5 minutes, check whether the air conditioner circuit is normal. If it is, then switch to the cooling mode, observe the voltage meter, run it for about 10 minutes, and observe whether the pressure gauge value is within the normal range. Touch the low-pressure valve with your hand to judge whether the low-pressure valve temperature is normal, and observe whether condensed water droplets are generated on the surface of the valve body.
During the process, listen to the sound of the fan and compressor. If there is an abnormal sound, stop the machine to check the problem. If there is no problem, observe whether there is water flowing out of the indoor unit drain pipe and whether the outflow water volume is normal.
After the above checks, switch to other modes and run it again. Only when everything is normal can it be said that the replacement of the compressor is completed.
