Hose

This is the flexible charging and connection hose used with condensing units and service equipment. It is a rubber core with a braided reinforcement and a working pressure of 19.6 MPa (200 kgf/cm2) on the 1/4 inch size and 9.8 MPa (100 kgf/cm2) on the 3/8 inch size - well above anything a refrigeration circuit will see, which is why the same hose is used for both refrigerant transfer and pressure testing.

The 1/4 inch hose has a 2.6 mm bore and 5.8 mm outside diameter with a minimum bend radius of 15 mm; the 3/8 inch hose has a 5 mm bore, 10 mm outside diameter and a 20 mm minimum bend radius. Both are rated from -40 C to +130 C, so they stay flexible in a cold room and do not soften on a hot discharge line.

The small bore is deliberate. A charging hose is not a transfer line: it carries liquid or gas at low flow while a system is being charged or evacuated, and a small bore keeps the volume in the hose low so that less refrigerant is lost when the hose is disconnected.

Use within the bend radius. A hose forced into a tight radius kinks, the braid takes the load, and the core collapses at the kink - the hose then looks fine but flows badly, which is easy to misdiagnose as a pump or valve problem. Check the end fittings for swaging cracks at each service; a hose that has been pulled off a connection by its body rather than its nut is a candidate for replacement.

Store hoses coiled rather than hanging, and keep them capped - a charging hose with an open end collects moisture and dirt, and that dirt ends up in the next system.