313D System Installation and Brazing 3

Question 1

When using an oxyacetylene torch for brazing refrigerant lines, the flame should be adjusted to a:

Accepted Answer

Neutral flame

Answer

A neutral flame provides the correct heat balance for brazing copper without introducing excess oxygen or carbon to the joint.

Question 2

What is the maximum recommended length of an unsupported horizontal refrigerant line run before a support hanger is required?

Accepted Answer

5 feet

Answer

Refrigerant lines should be supported at least every 5 feet horizontally to prevent sagging, vibration damage, and stress on joints.

Question 3

Before making a brazed joint on an existing system, the technician must first:

Accepted Answer

Recover all refrigerant from the system

Answer

Federal regulations require all refrigerant to be recovered before any brazing or repair that opens the refrigerant circuit.

Question 4

Which type of copper tubing is approved for use in refrigerant line sets for residential AC systems?

Accepted Answer

ACR (Air Conditioning and Refrigeration) grade copper

Answer

ACR-grade copper tubing is cleaned, dehydrated, and capped at the factory, making it suitable for refrigerant service.

Question 5

When routing refrigerant lines through a wall or floor, the technician should:

Accepted Answer

Install a protective sleeve or grommet to prevent abrasion

Answer

A sleeve or grommet protects the refrigerant lines from abrasion against sharp edges, which can cause premature leaks.

(313D) Residential Air Conditioning Systems Mechanic Certification Practice Test