What is the normal high pressure for car air conditioning?
4 Answers
Car air conditioning normal high pressure should be 1.3-1.7MPa (13-17kg/cm2 or 190-250Lbf/in2); normal low pressure should be between 0.15-0.25MPa (1.5-2.5kg/cm2 or 20-35Lbf/in2). 1. Car air conditioning system: The car air conditioning system is a device that cools, heats, ventilates and purifies the air inside the compartment. It can provide a comfortable riding environment for passengers, reduce driver fatigue and improve driving safety. Air conditioning has become one of the indicators to measure whether a car is fully functional. 2. Disadvantages of car air conditioning: When the air conditioning is turned on, it is best for passengers not to smoke in the car. Since the air inside the car circulates in a relatively closed environment when the air conditioning is on, firstly the smoke is not easy to dissipate, and secondly the tiny particles in the smoke will adhere to the air conditioning intake filter, causing long-term odor in the car. Regular professional cleaning and deodorizing maintenance of the air conditioning system is recommended.
Last time I went to the repair shop for maintenance, the mechanic specifically explained to me about the high pressure of the air conditioning system. Now that summer is here and driving times are longer, the high pressure value of the AC is crucial. The normal range is approximately 15 to 20 kilograms. When measured with a professional pressure gauge, if it exceeds 25 kilograms, it's too high. Excessive pressure could indicate poor heat dissipation from the condenser or overcharging of refrigerant, which may trigger the AC's protection mode and cause it to shut down automatically. If the pressure is below 10 kilograms, it's too low, suggesting a refrigerant leak or compressor issues. The safest approach is to have it checked once a year before summer starts. If the pressure is abnormal, never attempt to fix it yourself, as it's easy to damage the pipelines.
With twenty years of car repair experience, I check AC pressure daily. The normal high-side pressure actually depends on the weather: around 30°C, standard sedans should have a high-side pressure between 1.5 to 2.0 MPa. Just glance at the repair order numbers—if it's above 2.5, the cooling fan might be stuck or there's excessive refrigerant, making AC cooling worse; below 1.2 suggests the compressor may lack oil. Once, a customer's car had fluctuating pressure—turned out to be a clogged expansion valve. This value can be measured by connecting a pressure gauge to the blue cap port on the AC line, but remember, the pipes contain high-pressure gas—DIY disassembly is dangerous.
When I first bought the new car, I carefully studied the manual, which clearly specifies the standard for AC high pressure. For regular household vehicles, it's typically 150-250 PSI (approximately 10-17 kg), depending on the model and ambient temperature. I've observed that during midday under intense sunlight, the pressure can rise to 20 kg, but it drops back to normal once the cooling fan kicks in while driving. If the pressure gauge needle keeps climbing during idle parking, the AC should be turned off immediately. Last time, my neighbor's car had its pipeline burst due to excessive high pressure, costing over 3,000 yuan in repairs. It's advisable to have the mechanic check it during each maintenance service—just a small cost of a few dozen yuan.
