FREE 313D System Installation and Brazing Questions and Answers

Question 1

When brazing copper refrigerant lines, what is the primary purpose of flowing dry nitrogen through the tubing?

Accepted Answer

To prevent the formation of copper oxide scale inside the piping.

Answer

To cool the joint, allowing for a faster brazing process.

Answer

To increase the pressure within the lines, which helps the brazing alloy flow into the joint.

Answer

To act as a fluxing agent, cleaning the exterior of the pipe.

Question 2

A technician is preparing to braze a copper suction line to a steel compressor stub. Which of the following is essential for creating a strong, leak-free joint?

Accepted Answer

Applying a separate flux to the joint before heating.

Answer

Using a self-fluxing phosphorus-copper brazing alloy.

Answer

Heating only the copper tubing until it is cherry red before applying the brazing rod.

Answer

Quenching the joint with water immediately after the alloy flows.

Question 3

During the installation of a residential split system, what is a critical first step in preparing the copper tubing before making a brazed connection?

Accepted Answer

Cutting, deburring, and thoroughly cleaning the tube ends and fitting.

Answer

Flaring the end of the tube to ensure a tight fit.

Answer

Slightly denting the pipe to create a friction hold.

Answer

Applying a thick layer of flux to the inside of the tubing.

Question 4

A technician is installing a new outdoor condensing unit. According to general installation guidelines, what is a typical minimum clearance required above a top-discharge unit to ensure unrestricted airflow?

Accepted Answer

60 inches (152 cm)

Answer

6 inches (15 cm)

Answer

12 inches (30 cm)

Answer

24 inches (61 cm)

Question 5

When selecting a brazing alloy for joining two copper pipes in a standard residential AC system, which type of alloy is commonly used because it is self-fluxing?

Accepted Answer

A copper-phosphorus alloy

Answer

A tin-lead solder

Answer

An aluminum-silicon alloy

Answer

A high-silver, cadmium-free alloy

Question 6

Which of the following is a critical safety practice that must be followed when brazing refrigerant lines in an enclosed space?

Accepted Answer

Ensuring the area is well-ventilated to prevent the accumulation of harmful fumes.

Answer

Keeping the nitrogen purge pressure above 20 PSI to speed up the process.

Answer

Wearing standard sunglasses to protect from the bright flame.

Answer

Having a pressurized water extinguisher ready at all times.