1. Insufficient flow
1. The air-conditioning system leaks, causing insufficient refrigerant circulation in the system;
2. When the weather is very cold, the amount of refrigerant evaporation is insufficient;
3. The four-way valve is not well matched with the system, that is, the middle flow of the selected four-way valve is large but the system capacity is small;
4. Air conditioner reversing time. The general system design is that the four-way valve changes direction after the compressor stops for a certain period of time. At this time, the high and low pressure tends to balance, and it stops when the direction changes to the middle position. The next time it is started, the flow is insufficient due to the effect of the intermediate flow;
5. When the compressor starts, the flow is insufficient, and the inverter is more obvious.
2. Poor commutation
1. The coil is disconnected or the voltage does not meet the performance requirements of the coil, causing the spool of the pilot valve to fail to operate.
2. Due to external reasons, the pilot valve is partially deformed, causing the spool to fail to move.
3. Due to external reasons, the capillary tube of the pilot valve is deformed and the flow is insufficient, and the pressure difference required for reversing cannot be formed and cannot be operated.
4. Due to external reasons, the main valve body is deformed and the piston is stuck and cannot move.
5. The sundries in the system enter the four-way valve and block the piston or the main slide valve and cannot move.
6. When brazing the piping, the temperature of the main valve body exceeds 120 degrees, and the internal parts are thermally deformed and unable to operate.
7. The air-conditioning system refrigerant leaks, the refrigerant is insufficient, and the pressure difference required for reversing cannot be established and cannot be operated.
8. The refrigerant circulation volume of the compressor cannot meet the necessary flow of the four-way valve reversing.
9. When the frequency of the inverter compressor speed is low, the necessary flow required for commutation cannot be guaranteed.
10. The scroll compressor causes the system to produce hydraulic shock, which causes the four-way valve piston to be damaged and unable to move.
Three, gas maintenance
1. Touch the three pipes below the four-way valve by hand. If they are all hot, it means that the four-way valve is not in place and is in a state of air flow in the middle.
2. A small magnet can also be used, and the small magnet does not move with it when the direction is changed, which also indicates gas flow. Fill the system with a certain amount of refrigerant, and then it can be switched in place.
Four, maintenance without reversing
The faults are mostly not cooling or heating:
1. Insufficient refrigerant (only the system pressure is not comprehensive).
2. Fluorine leakage.
3. The valve body or capillary tube is deformed.
4. Whether the coil is energized and disconnected normally, and whether the voltage is normal.
5. Judge whether the pilot valve is operating: When the coil is turned on and off, there is a "click" spool impact sound, indicating that the pilot valve is operating normally. At this time, it is best to only energize the four-way valve so that the sound can be heard clearly.
6. The pilot valve operates normally, but the main valve body does not operate, indicating that the minimum operating pressure difference required for the four-way valve reversing has not been established, and refrigerant is charged into the system.
7. Hydraulic shock. It may be a. The installation direction of the four-way valve is wrong; b. The scroll compressor is used; c. The temperature in winter is too low; d. The stop valve is not opened.
Precautions for maintenance of four-way valve1. The first four pipe ports of the new four-way valve should be plugged with plastic plugs to prevent magazines from entering the four-way valve; pay attention to the position of the four-way valve slider before welding to the left of the internal structure of the four-way valve main valve body If it is in the middle or on the right, tap the valve body lightly and tap the valve block to the left.
2. The coil of the pilot valve must be removed before the four-way valve is welded to prevent the coil from being burnt out due to improper welding.
3. Before welding the four-way valve, you must wrap the four-way valve with a damp cloth, and weld the four-way valve assembly completely (using customized tooling operation later), pay attention to the direction of the flame during welding, and do not allow the flame to oppose the valve. The body is heated.
4. Wrap the four-way valve in the assembly with a damp cloth or immerse it in water for replacement. In order to control the relative angle between the pipes of the four-way valve assembly, you can remove a pipe and reinstall the new valve after welding. , And then disassemble and replace other pipe fittings.
During the replacement process, ensure that the inside of the new and old four-way valves are not burnt out, to ensure the welding quality of the new valve and the analysis effect after the old valve is returned;
5. When installing the four-way valve assembly, you must wrap the four-way valve with a damp cloth. At the same time, pay attention to the direction of the flame during welding, and do not allow the flame to heat the valve body;
6. When replacing the four-way valve, because the copper tube has been welded many times, try to use silver-containing solder as much as possible. If there is no silver-containing solder, you can use copper-phosphorus solder to weld with flux;
7. When the four-way valve is welded and cooled, care should be taken to prevent water from entering the valve body;
8. When welding, it should be filled with nitrogen as far as possible to reduce the generation of oxide scale. After welding, use nitrogen or compressed air to blow off the internal oxide scale of the four-way valve;
9. The refrigerant in the system must be discharged before welding the four-way valve assembly.
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