313D Practice Test Video Answers

1. B
Technicians must disconnect the power to ensure safety before diagnostics.

2. C
The metering device controls refrigerant flow to the evaporator, ensuring system efficiency.

3. B
R-410A is the eco-friendly replacement for older refrigerants like R-22.

4. C
Restricted airflow causes frost buildup and low suction pressure.

5. B
Evacuating to 500 microns ensures moisture and air removal.

6. C
Proper PPE is required when handling refrigerants due to frostbite risk.

7. B
Superheat confirms correct refrigerant charge and airflow balance.

8. B
The condenser coil releases absorbed heat outdoors.

9. B
Nitrogen flow prevents oxidation inside copper tubing during brazing.

10. C
Low-pressure switches prevent compressor operation under unsafe conditions.

11. B
The evaporator coil removes moisture as it cools indoor air.

12. B
This promotes compliance and ethics in professional practice.

13. B
Leak detectors identify leaks and ensure environmental compliance.

14. A
The compressor compresses vapor to high-pressure gas.

15. B
Accumulators prevent liquid refrigerant from reaching the compressor.

16. B
Hands-on learning reinforces safety understanding.

17. B
Subcooling helps verify the system charge and condenser performance.

18. C
Proper refrigerant recovery is a legal environmental requirement.

19. B
The suction line is large and cool, carrying vapor to the compressor.

20. A
Clamp meters measure electrical current safely.

21. B
A dirty condenser coil increases system head pressure.

22. B
Start capacitors provide torque for compressor startup.

23. B
Leaking valves cause low discharge pressure.

24. C
Variable-speed motors improve energy efficiency and comfort.

25. B
Calibration ensures accurate diagnostic readings.

26. B
Demonstrations and supervised practice ensure proper recovery technique.

27. D
Gay-Lussac’s Law relates pressure and temperature directly.

28. B
Mentoring should prioritize safe, accurate, and thoughtful work.

29. B
Duct or filter restrictions cause uneven cooling.

30. B
The sensing bulb regulates refrigerant flow to maintain superheat.

31. B
Applied learning reinforces theory through practice.

32. A
Oil separators return oil to the compressor while isolating refrigerant.

33. B
CSA develops standards for HVAC safety compliance.

34. C
Verifying airflow and duct integrity ensures the system can deliver proper cooling capacity before charging or testing.

35. A
Electronic leak detectors provide the most accurate results for small refrigerant leaks, far exceeding soapy water detection.

36. A
A vacuum pump removes air, moisture, and non-condensable gases to prevent system contamination and inefficiency.

37. B
After any refrigerant line repair, it’s essential to flush with nitrogen and pull a vacuum to remove contaminants before recharging.

38. B
Frosted suction lines typically indicate airflow restriction, commonly caused by a dirty evaporator coil or blocked return air.

39. B
Superheat and subcooling measurements are the standard diagnostic checks to confirm proper refrigerant charge and system balance.

40. B
Guided hands-on practice with mentor feedback is proven to improve skill retention and learner confidence in technical trades.