The rupture disc for a low-pressure centrifugal refrigeration machine is normally located on the:

• A. Compressor discharge
• B. Receiver
• C. Compressor suction line
• D. Compressor suction

Answer: (D)

A rupture disc in this context acts as a safety valve to protect the low-pressure side of the machine from overpressure. On a low‑pressure centrifugal system, the compressor suction line is the most vulnerable path if something goes wrong—such as a flow restriction, evaporator flooding, or a surge of vapor returning to the compressor. If suction pressure climbs above the design limit, that excess pressure can damage the compressor, seals, or crankcase. Placing the rupture disc on the compressor suction line provides immediate relief by venting excess pressure to the atmosphere before it can harm the compressor.

Locating the disc elsewhere (like on the discharge or receiver) wouldn’t protect the compressor from suction-side overpressure and could waste refrigerant or fail to prevent damage. After it vents, the disc must be replaced, since it’s a one‑time safety device.