Which of the illustrated valves is a...

Which of the illustrated valves is a conventional service valve with front and rear seats? See illustration GS-RA-69.

🔍 Key Concepts

• Conventional service valve used in refrigeration systems usually has three ports: inlet, outlet, and a gauge/service port • A valve with front and rear seats lets you isolate the system in different ways depending on how far the stem is backed off or seated • Look for a design that clearly allows flow in line with the piping, plus a separate connection that can be opened or closed by the stem position

💭 Think About

• Which illustration shows a valve that can both isolate a line and provide a gauge/service connection depending on stem position? • Which valve body is arranged in-line with the piping, with a stem that can be front‑seated (closing one side) or back‑seated (closing the service port)? • Eliminate any fittings that are only straight adapters or access fittings and could not practically have both front and rear seats inside

✅ Before You Answer

• Verify which option shows three distinct connections: inlet, outlet, and a service/gauge port controlled by the stem • Confirm that the stem arrangement would allow a back‑seated position (stem fully open to close off the gauge port while keeping line flow) and a front‑seated position (closing line flow while opening the gauge port to the isolated section) • Rule out any options that appear to be only an access fitting or a simple block or clamp without an adjustable stem that could create two seating positions

🔍 Key Concepts

💭 Think About

✅ Before You Answer