What Is a Four-Way Valve?

Four-way valve, hydraulic valve term, is a control valve with four ports. The four-way valve is an indispensable part of the refrigeration equipment. Its working principle is that when the solenoid valve coil is in a de-energized state, the pilot spool valve is moved to the left by the compression spring on the right side, and the high-pressure gas enters the capillary tube and enters the right piston chamber. On the one hand, the gas at the left end of the piston chamber is exhausted. Due to the pressure difference between the two ends of the piston, the piston and the main spool valve move to the left, so that the exhaust pipe communicates with the outdoor unit, and the other two pipes communicate, forming a refrigeration cycle.

Four-way valve

Four-way valve, hydraulic valve term, has four ports

Insufficient flow of four-way valve

1. The air-conditioning system leaks, causing insufficient refrigerant circulation in the system;

2. When the weather is very cold, the 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 and the system capacity is small;

4. Air conditioning reversing time. The general system is designed so that the four-way valve is switched after a certain period of compressor shutdown. At this time, the high and low pressures are balanced, and the switching is stopped at the intermediate position, that is, the four-way valve is not switched, and the main spool valve is stopped at the intermediate position. The next time it starts, the flow is insufficient due to the effect of intermediate flow;

5. When the compressor starts, the flow is insufficient, and the inverter is more obvious.

Four-way valve has poor commutation

1. The coil is disconnected or the voltage does not meet the coil performance requirements, 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 operate.

3. Due to external reasons, the capillary of the pilot valve is deformed, and the flow rate is insufficient, which cannot form the pressure difference required for the commutation and cannot be operated.

4. Due to external reasons, the main valve body is deformed, and the piston is stuck and cannot move.

5. Miscellaneous objects in the system enter the four-way valve and jam the piston or the main spool valve and cannot operate.

6. When brazing the pipe, the temperature of the main valve body exceeds 120 degrees, and the internal parts are thermally deformed and cannot operate.

7. Refrigerant leakage in the air-conditioning system, insufficient refrigerant, the pressure difference required for reversing cannot be established and cannot operate.

8. Refrigerant circulation of the compressor cannot meet the necessary flow of four-way valve reversing.

9. When the frequency of the inverter compressor 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 piston of the four-way valve to be damaged and cannot operate.

Four-way valve string gas maintenance

1. Touch the three pipes below the four-way valve with your hands. If all of them are hot, it means that the direction of the four-way valve is not in place.

2. A small magnet can also be used. When the small magnet does not move when the direction is changed, it is also a cross gas. Fill the system with a certain amount of refrigerant, and it can be reversed into place.

Four-way valve does not change direction

The faults are mostly not cooling or heating:

1. Insufficient refrigerant (incomplete identification based on system pressure only).

2. Fluorine leakage.

3. The valve body or capillary is deformed.

4. Is the coil on and off normal? Is the voltage normal?

5. Determine whether the pilot valve is operating: When the coil is turned on or off, there is a "click" valve core impact sound, indicating that the pilot valve is operating normally. At this time, it is better to only energize the four-way valve so that the sound can be heard clearly.

6. The pilot valve operates normally, and the main valve body does not operate, indicating that the minimum operating pressure difference required for the reversing of the four-way valve has not been established, and the system is charged with refrigerant.

7. Hydraulic shock. It may be a. The four-way valve is installed in the wrong direction; b. A scroll compressor is used; c. The temperature is too low in winter; d. The stop valve is not open.