In refrigeration terminology, low side pressure refers to which part of the system?

• A. Discharge side pressure
• B. Suction side pressure
• C. Liquid line pressure
• D. High-pressure side

Answer: (B)

Low side pressure is the pressure on the suction side of the refrigeration cycle—the path from the evaporator back to the compressor. As refrigerant absorbs heat in the evaporator, it boils into low‑pressure vapor. The compressor then draws this vapor in at suction pressure and increases it to the high-pressure discharge side. A suction (low-side) gauge measures this lower pressure, which is always less than the pressure on the high-pressure side, such as in the condenser and discharge line. The liquid line and high-pressure components sit on the opposite side of the cycle, where pressures are higher, so they belong to the high side rather than the low side.