In a Freon refrigerating system, how should the joints made of hard copper fittings be completed?

In a Freon refrigerating system, the use of hard copper fittings requires joints to be completed in a manner that ensures a secure and leak-proof seal. Soldering or brazing is the method used for these types of connections because it involves melting a filler metal that joins the copper fittings together. This not only provides a strong bond but also ensures that the joint can withstand the pressures and temperatures typical in a refrigerant system without the risk of leaks.

Soldering is typically used for lower pressure systems, while brazing, which involves a higher temperature and often a higher melting point filler material, is more suitable for systems that operate at higher pressures. This distinction is important because maintaining integrity in the system is vital to prevent refrigerant leaks, which can lead to inefficient operation or environmental damage.

The other methods listed, such as screwing or using flanges with gaskets, are generally not suitable for hard copper fittings in refrigerant applications. These options may not form as tight of a seal and can lead to potential leak issues over time. Therefore, soldering or brazing is the preferred method for ensuring reliability and safety within Freon refrigerating systems.