What is the normal pressure of car air conditioning refrigerant?
3 Answers
Under the condition of compressor speed at 1500~2000 rpm, the normal pressure of car air conditioning refrigerant is approximately 1.5~2.0 MPa for high pressure (discharge pressure) and 0.15~0.35 MPa for low pressure (suction pressure). Extended information is as follows: 1. Introduction to normal car air conditioning pressure: Normal high pressure should be 1.3-1.7 MPa (13-17 kg/cm2 or 190-250 Lbf/in2); normal low pressure should be between 0.15-0.25 MPa (1.5-2.5 kg/cm2 or 20-35 Lbf/in2). 2. Introduction to normal car air conditioning pressure at idle: At idle speed, if the ambient temperature is high, such as under direct sunlight in summer, the high pressure may be slightly higher, up to about 2.5~2.8 MPa, but generally it will not exceed 3.1 MPa, otherwise the pressure switch will be protected. If the low pressure is higher or lower than this range, it indicates that the expansion valve adjustment is abnormal. If the compressor has problems, it is not within this category.
I've dealt with many car air conditioning issues before. The normal pressure is generally between 150 to 250 psi on the high side and about 25 to 45 psi on the low side, depending on the ambient temperature. It tends to be higher in the hot summer and lower in the winter. I recommend using a pressure gauge to check. If the high pressure is too high, it might indicate a compressor failure, while low pressure suggests a refrigerant shortage or a leak, which needs to be replenished or repaired promptly. The air conditioning system is a closed loop, so don't overlook regular maintenance. It's best to have it professionally inspected once a year to extend its lifespan. Remember, when doing DIY work, wear safety goggles—high-pressure refrigerant discharge is dangerous. If you force the AC on when the pressure is abnormal, at best, you'll get poor cooling, and at worst, you could damage components, leading to costly repairs. I've encountered cases where owners tried to save time but ended up paying more for repairs, so safety first.
When I first started driving, I was also curious about the air conditioning pressure. Later, I bought a gauge to measure it myself and found that the normal high pressure is 150-250 psi, and the low pressure is 25-45 psi. In summer, when the temperature exceeds 30°C, the high pressure might exceed 250 psi, so be careful not to perform maintenance under high temperatures. If the pressure is too low or too high, the air conditioning will stop working and blow hot air, usually due to a lack of refrigerant or a blocked pipeline. I tried adding refrigerant myself but found it’s a technical task that’s easy to mess up if you’re not a professional, so now I leave it to the repair shop. In actual driving, stable air conditioning pressure saves fuel, especially before long trips—checking it can prevent surprises. Maintaining it well saves money and hassle, and don’t forget to check and replace the cabin filter at the same time, as it affects cooling performance. I recommend keeping a simple pressure gauge in the car, but avoid tampering with the pipes randomly.
