How Many PSI Should Car Refrigerant Be Charged To?

[DeBrooklyn]

When the car is idling, the high pressure of the refrigerant should be charged to approximately 1.3MPa, and the low pressure to about 0.35MPa. Below are detailed introductions to the charging methods: 1. Weighing Charging Method: The weighing charging method uses an electronic scale to measure the refrigerant. During operation, place the refrigerant cylinder on the tray of the electronic scale. Connect the dryer filter, charging hose, and three-way valve, purge the air from the connecting hose, and weigh the refrigerant. Subtract the required amount of refrigerant to be charged, note the remaining weight, and then slowly charge the refrigerant until the scale matches the remaining weight. 2. Pressure Gauge Charging Method: The pressure gauge charging method determines the charging amount based on the low-pressure suction pressure of the refrigeration cycle system. During operation, connect the refrigerant cylinder to the dryer filter, connecting hose, three-way valve, and vacuum pressure gauge, then proceed with charging. Observe the pressure gauge reading during charging. When the pressure gauge reaches 0.5~0.6MPa, close the three-way valve and let the compressor run. When the pressure gauge drops to 0, open the three-way valve again and adjust the pressure for a period until the suction pressure stabilizes. 3. Empirical Charging Method: The empirical charging method determines the charging amount based on the cooling performance of the air conditioner. The connection method is the same as the pressure gauge charging method. When the refrigerant is charged to a vacuum pressure gauge reading of 0.2~0.25MPa, close the three-way valve and run the system for 30 minutes until the compressor suction pipe shows condensation. 4. Quantitative Charging Method: The quantitative charging method uses a charging device to charge refrigerant based on the rated charging amount of the air conditioner. Select the appropriate scale on the measuring cylinder, open the corresponding valve to let the refrigerant flow into the measuring cylinder. When the refrigerant reaches the selected scale, open the charging device valve to let the refrigerant in the measuring cylinder flow into the refrigeration system.

[StEloise]

Last time my car's AC wasn't working, I bought a set of pressure gauges to test it. Actually, the normal low-pressure side should be between 25 to 45 PSI, and the high-pressure side between 200 to 250 PSI, but this really depends on the weather—higher on hot days and lower on cold days. Connect to the AC service port and start the engine to let the compressor run. Never add refrigerant directly—too high pressure can burst pipes, and too low results in poor cooling. Remember, each car model has different pressure requirements—check your owner's manual or online car forums. The safest bet is to have a digital pressure gauge, as the readings are clear at a glance. Unstable pressure might indicate a refrigerant leak or a failing compressor. A simple check of the AC outlet's temperature before driving regularly can help prevent issues.