Piping

Table of Contents

Chapter 1: Piping Materials and Fittings

Topics: Material compatibility; Sizing; Oil migration; Pipe vs tubing; Schedules and codes; Valves; Fittings; Cutting and joining pipe; Tubing materials and sizes; Cutting, flaring, bending, and joining tubing

Learning Objectives:

• Name the three main lines of piping in a refrigeration system.
• Explain why air conditioning and refrigeration piping must be sized correctly.
• Contrast pipe and tubing and explain why tubing is often preferred over piping.
• Explain how pipe is classified according to schedule.
• Name three methods of joining steel pipe.
• Explain how tubing is cut, flared, bent, and joined.
• Describe the step-by-step procedure for making a brazed joint.

Chapter 2: Discharge Line

Topics: Refrigerant condition; Pressure drop; Oil circulation; Piping layout, sizing; Refrigerant migration; Accessories

Learning Objectives:

• List the four functions of the discharge line in a refrigeration piping system.
• Explain the importance of pressure drop in piping and its effects on system operation.
• Define the term entrainment and explain why entrainment of oil is important.
• State the flow velocity needed for refrigerant vapor to entrain oil in horizontal piping and in vertical risers.
• Name some practical steps you can take to assure a good flow of refrigerant in horizontal piping.
• Describe ways of preventing refrigerant and oil migration to the compressor.
• Name and explain the purposes of three discharge-line accessories.

Chapter 3: Liquid Line

Topics: Refrigerant condition; Pressure drop; Oil circulation; Piping layout and sizing; Liquid receiver; Components, accessories, and insulation

Learning Objectives:

• Name the functions of the liquid line.
• Explain why it is desirable to have subcooling in the liquid line.
• Describe the effects of pressure drop in the liquid line on the operation of a refrigerant system.
• Describe the effects of flash gas formation on the performance of the system.
• Explain the purpose of a liquid receiver.
• Explain why each of the following devices is used in the liquid line: sight glass, solenoid valve, check valve.

Chapter 4: Suction Line

Topics: Lubricating oil; Pressure drop; Accumulators; Heat exchangers; Controls; Valves; Filters; Vibration eliminators; Insulation

Learning Objectives:

• Describe the functions of the suction line, its structural demands, and special design features.
• Explain why suction lines are pitched down toward the compressor.
• Explain how a double suction riser moves oil along with the refrigerant.
• Explain the function of an accumulator and a heat exchanger in a suction line.
• Describe the basic differences between evaporator pressure regulators and crankcase pressure regulators.
• Explain why it is necessary to insulate the suction line.
• Explain how a suction line for multiple compressors differs from a suction line for a single compressor.

Chapter 5: Piping Systems Maintenance

Topics: Dirt and scale; Piping expansion; Supports; Vibration; Corrosion; Leaks; Liquid hammer; Thermal insulation; Troubleshooting

Learning Objectives:

• Name at least four factors that cause piping problems and can lead to operating problems.
• Explain why cleanliness is essential when assembling refrigeration piping.
• Name at least three ways to allow for the expansion of piping.
• Describe the various ways of supporting horizontal and vertical pipe runs.
• Describe the damage that can be caused by vibration and tell how to protect piping from it.
• Define corrosion and explain how it can be prevented in refrigerant and water piping.
• Explain the importance of thermal insulation for refrigeration system piping.

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