4190. Which of the hand valve configurations for the gauge manifold set is the correct set up for removing the remaining refrigerant from the gauge manifold set with the discharge service valve back-seated in preparation for removing the gauge manifold set

Configuration C is correct; it establishes a flow path from the trapped refrigerant in the high-side of the manifold to the low-side suction, allowing the compressor to recover the remaining refrigerant before gauge removal. This is necessary because back-seating the discharge service valve isolates refrigerant in the high-side hose and manifold, and opening both hand valves connects the high-side, center, and low-side passages to facilitate refrigerant recovery without venting to the atmosphere.