Chunlan air conditioning maintenance knowledge; What are the detection methods of pressure value in air conditioning and refrigeration system?

1) During air conditioning and refrigeration operation (or "emergency" during forced refrigeration operation in winter), the pressure value of connecting the pressure gauge valve and the inflation tube to the ejector pin of the process port of the three-way stop valve for testing is the low pressure value during refrigeration operation, which is about 0.

5 MPa.

2) Run the air conditioner for heating, and connect the pressure gauge valve and air charging pipe as one end to the heating system (from the outdoor unit to the suction port of the compressor through the condenser), that is, connect to the process port in the air return pipe of the heating system to detect the pressure value, which is the low pressure value in the heating operation state.

Note: When the air conditioner kfr- 120lw cabinet is in heating operation, refrigerant can still be charged from the process port on the gas-liquid separator of the compressor.

(2) Detection method of high voltage.

1) When the air conditioner is in the heating operation state, the pressure value detected by integrating the pressure gauge valve, the inflation tube and the process port (the three-way stop valve of the outdoor unit is changed into the exhaust port of the compressor through the four-way valve) is the high pressure value in the heating operation state.

2) During the refrigeration operation of the air conditioner, the pressure value detected after the pressure gauge valve and the gas filling pipe (through the compressor exhaust pipe or related parts at the exhaust end) are connected to the process interface of the refrigeration system is the high pressure value in the refrigeration operation state.

(3) Test method of equilibrium pressure. After the air conditioner is turned off (or stopped), the high and low pressure values in the refrigeration system are measured, and the pressure values measured when reaching equilibrium are equal, which is the equilibrium pressure.

(4) Matters needing attention in pressure detection of refrigeration and heating systems.

1) When detecting low pressure (assuming there is no refrigerant in the system), when connecting to the low pressure port of the process port, the pressure value here is less than the atmospheric pressure value during refrigeration operation, which will suck air or water molecules in the air into the system, and the effect is not good. It should also be noted that when checking the refrigeration pressure value in winter, the process mouth is prone to frost. Because the gas filling pipe is removed from the process port, sometimes the temperature of the thimble reaches freezing point or the O-ring in the thimble is damaged and cannot be reset normally, resulting in refrigerant leakage. Under normal circumstances, after the system pressure is balanced, the operation is to close the heating process port of the air conditioner and take off the gas filling pipe.

2) When the heating state is set to work, high pressure is detected. When it is connected to the process port for inspection, due to the high pressure in the system, it is easy to spray refrigerant and frozen oil from the gas charging pipe, resulting in frostbite of fingers or loss of refrigerant and frozen oil from the heating system. In general, air conditioners should be cooled during normal operation. When the pressure is low, the gas filling pipe should be connected to or removed from the process port.

3) When testing the equilibrium pressure in summer, it should be noted that the outdoor ambient temperature is too high and the equilibrium pressure of the refrigeration system is high. After refrigeration operation, the equilibrium pressure will be slightly higher.

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