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

2% silver

Answer

5% silver

Answer

45% silver

Question 2

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

Accepted Answer

Prevent internal oxidation and scale formation

Answer

Cool the joint faster

Answer

Increase brazing temperature

Answer

Reduce silver content needed

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

Heat joint, insert tube, apply flux, braze

Answer

Apply filler, heat joint, insert tube, cool quickly

Answer

Insert tube, heat joint, apply filler, apply flux

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

1/8 inch per foot

Answer

1/2 inch per foot

Answer

1 inch per foot

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

Pipe reamer

Answer

Swage block only

Answer

Pipe bender

Question 6

During a residential AC installation, the outdoor condenser unit should be elevated above grade to:

Accepted Answer

Prevent flooding and allow air circulation beneath the unit

Answer

Reduce refrigerant pressure drop

Answer

Lower the center of gravity for stability

Answer

Reduce compressor vibration noise

Question 7

What is the purpose of adding a trap in the suction line when the evaporator coil is located above the condensing unit?

Accepted Answer

To prevent oil from draining back to the compressor during the off cycle

Answer

To reduce refrigerant velocity

Answer

To increase suction pressure

Answer

To trap liquid refrigerant before the compressor