3.0.1 — General Learning Outcomes

Upon successful completion of this section, the apprentice will be able to:

• Identify refrigeration system valves by construction, function, and location; read valve symbols in drawings; and describe the five system goals that every valve or accessory device serves.
• Describe how solenoid valves and check valves control flow, diagnose stuck-open and stuck-closed faults, and verify proper operation using coil voltage, temperature, and pressure checks.
• Explain how TXVs, EEVs, and fixed metering devices meter refrigerant, compare their operating principles, and perform systematic troubleshooting using superheat and pressure measurements.
• Identify pressure relief valves, rupture devices, and high/low-pressure safety cutouts; explain the correct response to a relief event; and describe why safety device setpoints must never be arbitrarily adjusted.
• Describe the purpose of service valves and access ports, apply safe hose connection and isolation practices, and explain correct hand valve operation to prevent seat erosion and packing leaks.
• Explain how water regulating valves control condensing pressure in water-cooled equipment and identify the common causes of hunting and setpoint drift.

3.0.2 — Section 2 — Lessons at a Glance

Section 2 progresses from fundamental valve identification through metering and safety devices to the service valves and access ports used in daily commissioning and maintenance work.

3.0.3 — Key Terms — System Goals of Valves & Accessories

Every valve or accessory device in a refrigeration system exists to achieve one of five goals. Recognizing which goal a device serves is the first step in identifying it and diagnosing it correctly.