Air Conditioning Repair Installation and Evacuation Procedures 4

Question 1

A dual-stage vacuum pump should have its oil changed:

Accepted Answer

After each use or when the oil appears dark and contaminated

Answer

Vacuum pump oil absorbs moisture during system evacuation and should be changed after every use to maintain the pump's ability to achieve deep vacuums.

Question 2

What is the correct refrigerant line sizing rule regarding the suction line versus the liquid line?

Accepted Answer

The suction line is always larger in diameter than the liquid line

Answer

Suction line carries low-pressure vapor (low density) and must be larger diameter than the liquid line to maintain proper refrigerant velocity and oil return.

Question 3

When an AC outdoor unit is installed on a rooftop, the mounting platform must:

Accepted Answer

Be structurally rated for the unit weight and allow for vibration isolation

Answer

Rooftop installations require structurally adequate, properly rated supports with vibration isolation pads to protect both the unit and the roof structure.

Question 4

Which EPA regulation governs the handling and recovery of refrigerants during AC service and installation?

Accepted Answer

Section 608 of the Clean Air Act

Answer

EPA Section 608 prohibits venting refrigerants and requires certified technicians to use approved recovery equipment during service, maintenance, and installation.

Question 5

What is 'triple evacuation' (also called 'three-step evacuation') used for?

Accepted Answer

Removing moisture more effectively by breaking vacuum with dry nitrogen between pulls

Answer

Triple evacuation involves pulling vacuum, breaking with dry nitrogen, then repeating twice more — each cycle draws out more moisture than a single long pull.

Air Conditioning Repair Practice Test

Air Conditioning Repair Practice Test

Air Conditioning Repair Installation and Evacuation Procedures 4