313D System Installation and Brazing 2

Question 1

When brazing copper refrigerant lines, what minimum silver content is required for the brazing alloy used in most residential AC applications?

Accepted Answer

15% silver

Answer

Brazing alloys with at least 15% silver content are typically required for refrigerant line brazing to ensure strong, leak-free joints.

Question 2

Nitrogen should be flowing through refrigerant lines during brazing primarily to:

Accepted Answer

Prevent internal oxidation and scale formation

Answer

Flowing dry nitrogen through the tubing during brazing displaces oxygen and prevents the formation of copper oxide scale inside the lines.

Question 3

What is the correct sequence for making a brazed refrigerant line connection?

Accepted Answer

Insert tube, apply flux, heat joint to brazing temp, apply filler

Answer

The proper sequence is to insert the tube fully, apply flux if needed, heat the joint evenly to brazing temperature, then apply the filler rod at the joint.

Question 4

When installing a split-system air conditioner, the indoor unit's condensate drain line should be pitched at a minimum slope of:

Accepted Answer

1/4 inch per foot

Answer

A minimum slope of 1/4 inch per foot ensures proper gravity drainage of condensate without pooling.

Question 5

Which tool is used to properly size copper tubing for flare or swage connections during installation?

Accepted Answer

Tubing cutter and deburring tool

Answer

A tubing cutter makes a clean, square cut and the deburring tool removes the inner burr to ensure a leak-free connection.

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

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

313D System Installation and Brazing 2