What is the appropriate pressure for adding refrigerant to a car air conditioner?
2 Answers
For car air conditioner refrigerant charging, the appropriate pressure ranges are 150 to 250 kPa for the low pressure side and 1300 to 1500 kPa for the high pressure side. After completing the refrigerant charging, close the low-pressure manual valve on the manifold pressure gauge, shut off the injection valve on the refrigerant canister, stop the engine, and quickly remove the manifold pressure gauge from the compressor to prevent excessive refrigerant leakage. There are two methods for charging car refrigerant: it can be done from the high-pressure side or the low-pressure side. These two methods differ significantly due to the different states of the refrigerant being charged. The high-pressure side method involves charging liquid refrigerant, which is suitable for initial charging after leak detection and vacuuming. Note that this method requires the engine to be off and the refrigerant canister to be inverted. The low-pressure side method involves charging gaseous refrigerant, which is slower and typically used for topping up refrigerant.
Once my car's air conditioning stopped cooling in the summer, and when I tried adding refrigerant myself, I realized how crucial pressure is. The standard low pressure should be between 25 to 35 psi, and the high pressure around 200 to 250 psi, depending on the ambient temperature; higher temperatures mean higher pressures, and the most accurate readings are usually taken in environments between 27 to 32 degrees Celsius. But don’t attempt this casually—I added a bit too much, and the pressure spiked too quickly, nearly damaging the compressor. Luckily, nothing major happened. I recommend taking it to a professional shop where technicians can use proper gauges to measure and adjust it to the right range, and they can also check for refrigerant leaks or system blockages. Regular maintenance of the AC pressure can prevent breakdowns on the road, ensuring both safety and fuel savings. Remember, incorrect AC pressure not only reduces cooling efficiency but could also lead to expensive repairs.
