15.12.1 Capturing Refrigerant in the Liquid Receiver Capturing refrigerant in the liquid receiver is called a pumpdown. It is performed by closing the liquid receiver outlet valve (frontseated) while the compressor is running. When pumping down, sometimes the compressor shuts off on a low- pressure control before the pumpdown is system that has a liquid receiver with two service valves (inlet and outlet) can store the refrigerant while the area in need of repair is opened. See Figure 15‑18. The procedure is not recovery because it does not remove the refrigerant to a container outside the system. It captures (traps) most of the refrigerant in the liquid receiver, with residual refrigerant residing in the condenser and hot gas discharge line. Suction service valve Discharge service valve Goodheart-Willcox Publisher Figure 15‑18. A system that has a liquid receiver with two service valves (inlet and outlet) can be pumped down to capture most of the refrigerant charge while low-side repairs are made. 274 Heating and Cooling Essentials Copyright Goodheart-Willcox Co., Inc.