What are the normal high and low pressures for car air conditioning?
2 Answers
High pressure is around 1.5-2.0 MPa, while low pressure is around 0.15-0.35 MPa. Below is relevant information about car air conditioning: 1. Air Conditioning Layout: Different types of air conditioning systems have different layout methods. Currently, integrated heating and cooling air conditioning systems are widely used in passenger cars. The layout involves assembling components such as the evaporator, heater radiator, centrifugal blower, and control mechanisms together, forming what is known as the air conditioning unit assembly. 2. Air Conditioning Components: Modern air conditioning systems consist of a refrigeration system, heating system, ventilation and air purification devices, and a control system. Car air conditioning generally includes components such as the compressor, electronically controlled clutch, condenser, evaporator, expansion valve, receiver-drier, piping, condenser fan, vacuum solenoid valve, idle speed controller, and control system. Car air conditioning is divided into high-pressure and low-pressure lines. The high-pressure side includes the compressor output side, high-pressure lines, condenser, receiver-drier, and liquid lines; the low-pressure side includes the evaporator, accumulator, return lines, compressor input side, and compressor oil sump.
I've been repairing cars for over 20 years and have extensive experience with common AC pressure issues. The normal low pressure should be between 25 to 45 psi, while the high pressure typically ranges from 200 to 250 psi. These values are significantly affected by temperature - during hot summers, the high pressure may exceed 260 psi, and in winter, the low pressure can drop below 20 psi. If the low pressure is too low (below 20 psi), it could indicate refrigerant leakage or compressor failure. Excessively high pressure (above 260 psi) might suggest condenser cooling issues or expansion valve blockage. I recommend regularly checking with an automotive pressure gauge, especially before seasonal changes, to prevent minor issues from escalating. Neglecting these can lead to AC cooling failure and increased fuel consumption, making costly repairs unavoidable.
