What pressure should car air conditioning be charged to?
2 Answers
Car air conditioning should be pressurized to around 20-30 bar, which should be higher than the working pressure of the car air conditioning system. Nitrogen is generally used for pressurization and leak detection in car air conditioning systems. More details are as follows: 1. When pressurizing and checking for leaks in the car air conditioning system, use soapy water to inspect the connections of the air conditioning pipes. Whether pressurized from the high or low side, the pressure inside the system will eventually balance. Typically, nitrogen is added to the system from the high side, but Freon can also be added to the system and checked with a halogen leak detector, though this method is less effective than using soapy water. Since Freon operates at lower pressure within the system, minor leaks may be harder to detect. 2. Once the refrigeration system has been evacuated to the required vacuum level and no leaks are detected, refrigerant can be added to the system. Before charging, determine the correct amount of refrigerant to add, as too much or too little will affect the air conditioning's cooling performance. The compressor's nameplate usually indicates the type and amount of refrigerant required. 3. When using the car air conditioning system, it is important to maintain and service it properly. Avoid adjusting the air vents randomly. Some drivers do not pay attention to the direction of the airflow, which can prevent the air conditioning from performing optimally. According to the principle that cold air sinks and warm air rises, the correct approach is to direct the vents upward when cooling and downward when heating.
I remember repairing my car's air conditioning last summer, and the incorrect pressure I added resulted in poor cooling performance. Generally, the low-pressure side of a car's AC system should be between 25 to 40 PSI, while the high-pressure side ranges from 150 to 250 PSI, depending on ambient temperature: slightly higher in hot weather and lower when it's cooler. When I checked with a pressure gauge back then, the low pressure was only 20 PSI—too low to provide adequate cooling. After adjusting it to 30 PSI at a repair shop, it worked fine again. However, before attempting DIY repairs, safety must be ensured. The AC system is sensitive—excessive pressure can damage the compressor, while insufficient pressure may lead to refrigerant leaks. So, I recommend consulting your vehicle’s manual or seeking professional help, as incorrect AC pressure adjustments might even affect the entire car’s electrical system, making it not worth the risk.
