Where is the refrigerant stored when pumping down an AC unit?

When pumping down an AC unit, the refrigerant is stored in the condenser. This process involves removing the refrigerant from the evaporator and collecting it in the high-pressure side of the system, specifically the condenser. The refrigerant is in a gaseous state when it enters the compressor, but it condenses into a liquid state in the condenser as it releases heat.

The condenser's design and function allow it to handle the high-pressure refrigerant effectively during this process, making it an ideal location for the refrigerant to be stored temporarily while maintenance or repairs are conducted on the evaporator or other components of the system.

The other options do not serve as proper storage for the refrigerant during a pump-down. The evaporator coil functions to absorb heat, the expansion valve regulates refrigerant flow into the evaporator, and the compressor housing consists of components that circulate and compress the refrigerant rather than store it.