Systems containing more than 6.6 pounds (2.99 kg) of refrigerant shall have stop valves installed at the following locations:
- The suction inlet of a compressor, compressor unit, or condensing unit.
- The discharge of a compressor, compressor unit, or condensing unit.
- The outlet of a liquid receiver.
- Systems that have a refrigerant pumpout function capable of storing the refrigerant charge, or are equipped with the provisions for pumpout of the refrigerant.
- Self-contained systems. [ASHRAE 15:9.12.4]