A/C Systems

The figure shows the main sources of refrigerant leaks according to the car manufacturers. A maximum refrigerant loss of 10 to 30 g at the compressor shaft is generally considered unavoidable. 42 to 83 g of refrigerant loss (10 to 20 g from the hose system, 2 to 3 g from each O-ring) is considered "normal" for each year of operation.

In the newly developed air conditioning systems, the dryer condenser and expansion valve evaporator are manufactured together in order to reduce the number of joints and thus the leakage (52 g leakage per year).

Source: Emission of the refrigerant R-134a from mobile air conditioning systems, Dr. Winfried Schwarz.

The refrigerant is pressurized with the help of the compressor. When the pressure and temperature of the refrigerant increase, it becomes liquid as it passes through the condenser at a temperature of approx. 60°C. When the vehicle is moving, the condenser is cooled by the air flowing through it, in other cases this is done by the condenser fan. The pressurized liquid refrigerant flows through the expansion valve, expands and loses pressure. In the evaporator, the liquid refrigerant evaporates and absorbs heat. The evaporator and the surroundings cool down from "-10°C" to "-18°C". The evaporator fan controlled by the driver pushes the cool air into the car. The cycle is repeated when the refrigerant becomes liquid again.

Nitrogen gas delivers perfect results in air conditioning systems. Nitrogen is a dry and inert gas that is cheap and easy to obtain. A pressure regulator is required to keep the pressure under control. Suitable devices can be found in stores that sell welding equipment. You will also need changeover fittings to connect to the existing air conditioning manifold.

Nitrogen gas facilitates the search for refrigerant leaks.
When searching for leaks under pressure, do not use compressed air that contains moisture that will damage the air conditioning system.
Nitrogen dries out the air conditioning system and shortens the duration of the vacuum.
Nitrogen gassing before filling the system with refrigerant is an effective method for drying and flushing. For this purpose, one end of the air conditioning system is left open to the atmosphere. The other end is connected to the A/C service manifold and the nitrogen hose, and then pressurized gas is fed into the system. In this way, the moisture in the system is removed. Another advantage of using nitrogen is the reduction in vacuum time at low levels.