Which of the following is not a pressure regulating valve type used in refrigeration systems?

• A. Evaporator pressure regulator valve
• B. Two-temperature valve
• C. Case pressure control
• D. Gate valve

Answer: (D)

Pressure regulating valves are used to hold or control a specific pressure in a part of the refrigeration system by throttling refrigerant flow. An evaporator pressure regulator valve keeps the evaporator at a set pressure, so the evaporating temperature remains within design and the system isn’t run too low on pressure. A two-temperature valve is used in systems serving zones or evaporators with two different temperature requirements, modulating flow to maintain those two setpoints. Case pressure control maintains the pressure inside the refrigerated case, helping to keep the display case at the correct cooling level and ensuring consistent operation of the circuit feeding that space. A gate valve, by contrast, is designed to open or close flow; it does not modulate or regulate pressure. So, the gate valve is not a pressure regulating valve type.