In a low-pressure centrifugal air-conditioning appliance, which component is the lowest access point used for charging?

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

Answer: (C)

The main idea is where to introduce refrigerant into a low‑pressure centrifugal system for a proper, effective charge. The evaporator charging valve is the lowest access point in the system and sits on the low‑pressure side right at the evaporator. Adding liquid refrigerant there ensures the charge goes directly into the evaporator, promotes proper filling from the bottom of the loop, and helps purge any air or noncondensables before the refrigerant moves toward the compressor. Charging from higher or non‑low‑pressure points can lead to improper distribution, air pockets, or even liquid entering the compressor path.

The other access points are not used for charging: the suction service valve is a service port on the low‑pressure line but not the designated charging point, the discharge service valve is on the high‑pressure side, and the condenser inlet valve is not involved in the charging process.