Course: HET 119 HVACR Electricity II

Lab Assignment

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Week 15 Lab Assignment: Troubleshooting HVAC/R Systems

Recommended Materials
1. Lab Sheet
2. Pencil and paper
3. HVAC Textbook
4. Internet Search
5. A Low Temperature Refrigeration System

Scope

This lab will help the student to understand how to use electrical diagrams and test equipment to troubleshoot Control Devices in HVAC/R systems. The student will wire controls to loads in combination circuits.

Procedures

1. Use the diagram below, resolve the service problem.
2. If equipment is available, use it to help visualize the problem.
3. Have the instructor specify the controls you will need for this assignment.
  1. a.     The problem: On a walk-in freezer, the customer called about having the product warming up.
  2. The freezer thermostat set-point is -10° F.
  3. The compressor is not operating.
  4. The Freezer temperature is 30° F.
  5. The condenser fan motor is not running.
  6. The evaporator fan motor is in operation.
  7. You measured 0 Volts across the contactor contacts.
  8. You measured 0 Volts across the terminal T1 and T2.
  9. The compressor is room temperature
  10. You measured 230 Volts across the refrigeration thermostat.
  11. The defrost timer is set for compressor operation (Terminal 4 and 1 is closed).
  12. The voltage is 230 Volts at the defrost timer motor.
  13. Have the instructor to demonstrate the problem after you have completed your assignment.

Research Questions

1. What steps would you use to locate the problem? Be detail and itemize the steps. (Need voltage or resistance readings.)
2. Why do you believe this is the solution to the problem?
3. What other issues could be the problem? Why?

Click on the file below to download the Lab Assignment
- HET 119 Wk 15 Lab.docx (79.42 KB)