Series 430: Air Conditioning/Refrigeration
Course 439: System Troubleshooting
Discusses the keys to effective troubleshooting and emphasizes the importance of safety. Details a step-by-step procedure to use when troubleshooting. Covers the use of a troubleshooting flowchart. Examines three sample problems, leading the trainee through the steps necessary to locate the problem in each example.
TPC Training Systems is authorized by IACET to offer 0.5 CEUs for this program.
Lesson 1 - Preparation for Troubleshooting
Mechanical refrigeration systems; Keys to effective troubleshooting; Safety in troubleshooting; Tools and equipment; Supplies; Human relations skills
- Give an example of each of the following applications: process refrigeration, commercial refrigeration, process air conditioning, comfort air conditioning.
- Tell what knowledge is essential for an effective troubleshooter to have.
- Tell what safety precautions must be followed when dealing with the mechanical, electrical, chemical, and environmental hazards involved in troubleshooting.
- List the necessary tools, equipment, and supplies needed to perform troubleshooting procedures.
- Explain why human relations skills are important to the refrigeration system troubleshooter.
Lesson 2 - Troubleshooting Procedures
Six steps of troubleshooting; Avoiding a recurrence of the problem
- Name the six basic steps in the troubleshooting procedure.
- Explain why it is important to collect information from the equipment operator when a system is malfunctioning.
- Explain what type of information is contained on a nameplate and in the operations log of a system.
- Explain the structure and use of troubleshooting charts.
- Explain how to set up a preliminary checklist and how to select the most likely components and subsystems for further examination.
- List items to check out after making repairs to a refrigeration system.
Lesson 3 - Troubleshooting Electric Controls
Troubleshooting flowchart; Checking the contactor; Faulty coils; Relays and switches; The power side
- Explain how to use a troubleshooting chart.
- Explain how to isolate a control circuit failure from a motor circuit failure.
- List the causes of abnormally high control circuit resistance.
- Explain the difference between using an ohmmeter and using a voltmeter to check for a closed electric switch.
- Describe how to check contactor coils and motors for shorts and opens.
Lesson 4 - Troubleshooting Pneumatic Controls
Equipment and tools; Checking the control air supply; Output pressure test; Checking for air leaks; Checking other controllers; Actuator problems; Thermostat adjustments
- Describe the symptoms of control air contamination and explain how to remedy it.
- Explain how to check thermostat output pressure.
- List at least three kinds of actuator problems and explain how to solve them.
- Describe the calibration procedure and explain its purpose.
- Explain how to calibrate a pneumatic controller.
Lesson 5 - Troubleshooting the Refrigerant Circuit
Preliminary checks; Analyzing the complaint; Checking refrigerant pressures; Checking refrigerant charge; Checking for refrigerant leaks; Compressor cycling; Checking high-side components; Low-side problems, Distribution problems
- Distinguish between a refrigerant circuit problem and a conditioned-medium problem.
- Explain the procedure for checking refrigerant charge.
- Name major causes of variance in head and suction pressures.
- Explain how to isolate the cause of compressor short cycling.
- Explain how to use head-pressure readings and suction-pressure readings in diagnosing refrigeration problems.