When adding refrigerant from a service cylinder through the suction service valve, how must the cylinder be positioned?

When adding refrigerant from a service cylinder through the suction service valve, the cylinder must be positioned upright. This position allows for the proper flow of refrigerant into the system. In an upright position, the refrigerant vapor, which is the preferred form for most refrigerant types used in air conditioning and refrigeration systems, can escape first. This helps ensure that only the gas phase of the refrigerant enters the suction line, reducing the risk of liquid refrigerant entering the compressor, which could lead to damage or operational issues.

Positioning the cylinder improperly, such as on its side or inverted, could cause liquid refrigerant to enter the line, leading to potential hazards and equipment damage. Additionally, having the cylinder at a 45-degree angle may not provide a consistent flow of vapor or liquid that is desirable when charging a system. Therefore, maintaining the cylinder upright ensures safe and efficient refrigerant transfer during servicing.