What is the correct method for charging refrigerant in a car air conditioning system?
2 Answers
The correct method for charging refrigerant in a car air conditioning system is: 1. Prepare the necessary tools and materials such as an automotive refrigerant recovery/recharge machine and refrigerant; 2. Connect the hoses of the automotive refrigerant recovery/recharge machine to the high and low pressure pipes of the car's air conditioning system; 3. Perform vacuum extraction on the car's air conditioning system; 4. Set the appropriate charging capacity, time, and type on the refrigerant recovery/recharge machine; 5. The refrigerant recovery/recharge machine will automatically begin adding refrigerant. Functions of car air conditioning: 1. Achieves cooling effect through continuous circulation and transformation of refrigerant; 2. Draws in fresh outside air for ventilation and air exchange, preventing windshield fogging; 3. Uses engine coolant, waste heat, or heat generated by a burner as a heat source, which is then heated by the heater and blown into the cabin by the blower to raise the temperature for heating; 4. Removes dust, odors, smoke, and toxic gases from the cabin air, freshens the cabin air, humidifies the cabin air, and increases the relative humidity of the cabin air.
I've done refrigerant charging several times, and it's not actually difficult but requires caution. First, ensure there are no leaks in the AC system by applying soapy water to pipe connections and valves to check for bubbles—if there's a leak, fix it first. Then, perform a vacuum evacuation by connecting a vacuum pump to the high and low-pressure ports, running it for 15-20 minutes to dry and remove air from the system, stopping when the gauge reads -30 inches of mercury. Next, add new refrigerant, being careful not to exceed the system's specified capacity—typically 450-600 grams of R134a for small cars. Connect the refrigerant can to the low-pressure port, invert the can, and slowly release the refrigerant while monitoring the gauge to keep it within the 25-45 psi range. After charging, start the engine and turn the AC to maximum fan speed to check if the air vent blows cold. Wear gloves and goggles throughout to prevent frostbite, and inspect all pipes afterward. Don’t overfill—excess refrigerant can damage the compressor. Simple, right? But it's best to do this in a well-ventilated garage to minimize risks.
