How to recharge refrigerant in car air conditioning?
2 Answers
There are two methods to recharge refrigerant in car air conditioning: 1. Charge through the bypass hole of the compressor discharge valve, known as high-side charging. This method involves adding liquid refrigerant and is characterized by safety and speed, making it suitable for the initial charging of the refrigeration system, i.e., after leak detection and vacuuming. 2. Charge through the bypass hole of the compressor suction valve, known as low-side charging. This method involves adding gaseous refrigerant and is characterized by slower charging speed, making it suitable for refrigerant replenishment in the system. Refrigerant is the working fluid used in refrigeration and air conditioning systems to transfer heat energy and produce cooling effects. In air conditioning systems, it is a substance that facilitates heat transfer through evaporation and condensation, commonly known as Freon.
I was a bit nervous when I recently recharged the refrigerant for my car's air conditioning. Before starting, I checked the information to ensure safety. First, turn off the engine and the AC system, then locate the low-pressure charging port in the engine bay—usually a small valve with a blue cap. Wear protective gloves and connect the pressure gauge tool. Start the vehicle and turn the AC to maximum cooling, then observe the pressure reading. If the pressure is below the standard value (e.g., normal AC pressure is around 25-35 PSI), slowly open the refrigerant can valve to recharge. Keep the process steady and avoid rushing, as excessive pressure may cause pipe bursts. After recharging, test if the cooling effect is restored. Personally, I recommend beginners not attempt this themselves—leakage risks exist—and to rely on professional shops for reliability.
