Where is the lowest access point on a low-pressure centrifugal air-conditioning appliance?

• A. Evaporator charging valve
• B. Suction service valve
• C. Discharge service valve
• D. Condenser inlet valve

Answer: (A)

Charging a low‑pressure centrifugal chiller is easiest when you connect at the lowest point in the system. In this type of setup, the evaporator sits at the bottom of the circuit, so the evaporator charging valve is physically the lowest access point. Using that valve for charging ensures liquid refrigerant can gravity-feed into the evaporator, helps purge air and avoid trapping vapor in the compressor, and provides a straightforward path for introducing refrigerant directly where it’s needed.

The other valves are located higher up on the loop—the suction service valve on the low‑pressure, upstream side near the compressor; the discharge service valve on the high‑pressure side; and the condenser inlet valve on the condenser line. None of these occupy the bottom-most point of the system, so they aren’t used as the primary charging access.