What causes low low pressure and high high pressure in car air conditioning?
1 Answers
The reason for low low pressure and high high pressure in the air conditioning system is poor circulation in the system. Focus on checking the following aspects: clogged capillary tube (or expansion valve), such as dirt blockage or ice blockage. Clogged dryer filter. Kinked connection pipes causing flow obstruction, shut-off valve not fully open, four-way valve not properly aligned, or dirty condenser tubes. Here are the relevant details: 1. Measure the high and low pressure of the air conditioning system while the engine is idling. 2. The normal high pressure for car air conditioning should be 1.3-1.7MPa (13-17kg/cm2 or Lbf/in2); the normal low pressure should be between 0.1-0.25MPa (1-2.5kg/cm2 or 15-35Lbf/in2). If the low pressure is higher or lower than this range, it indicates improper adjustment of the expansion valve. Compressor issues are not included in this category. When the engine throttle is increased, the measured low pressure should decrease with engine speed—the faster the speed, the greater (faster) the pressure drop. This indicates good compressor performance; otherwise, it suggests a compressor fault. 3. Note that car air conditioning pressure is highly dependent on ambient temperature (the working environment of the condenser).
