What is the normal pressure of automotive air conditioning refrigerant?
2 Answers
The pressure of automotive air conditioning refrigerant varies under different conditions: 1. When the compressor is running at 1500 to 2000 rpm, the high pressure is approximately 1.5 to 2.0 MPa, and the low pressure is around 0.15 to 0.35 MPa. 2. In idle conditions, if the ambient temperature is high and under direct sunlight, the high pressure may be slightly higher, reaching about 2.5 to 2.8 MPa, but it generally does not exceed 3.1 MPa. Under normal circumstances, cars do not need to add refrigerant for 3 to 5 years. However, sometimes if the cooling effect of the refrigerant is poor, it may need to be replenished. After the air conditioner has been running normally for a while, if the air blowing on you feels cool and quickly reaches the set temperature, and the outdoor compressor operates intermittently like a refrigerator, it indicates normal functioning. Otherwise, it might be necessary to add refrigerant.
I've been repairing cars for many years and often deal with air conditioning issues. The normal refrigerant pressure is approximately 25 to 45 psi on the low-pressure side and around 200 to 250 psi on the high-pressure side, depending on the ambient temperature. On hot days, the high pressure may rise to 300 psi, while it drops in cold weather. Factors affecting pressure aren't just temperature—it also includes the load on the AC system. For example, when the temperature difference between inside and outside the car is large, the compressor works more frequently, leading to higher pressure. Incorrect pressure can cause major problems. If it's too high, it may indicate a compressor or condenser failure; if too low, it could mean a refrigerant leak. Never tamper with the high-pressure line yourself—it's prone to explosion. Just connect a professional pressure gauge to the vehicle's port for measurement. I recommend checking every six months, especially before summer, to maintain good condition—this ensures the AC runs efficiently and keeps you cool while saving fuel.
