Air Conditioning Repair Installation and Evacuation Procedures 3

Question 1

What happens if a technician charges an AC system with non-condensable gases (such as air) still present?

Accepted Answer

High-side pressure will be abnormally elevated

Answer

Non-condensable gases raise head pressure above normal because they occupy condenser volume without condensing, reducing system efficiency and capacity.

Question 2

The recommended maximum lineset length without adding extra refrigerant charge for most mini-split systems is typically:

Accepted Answer

25 feet (pre-charged factory amount)

Answer

Most mini-split systems are pre-charged at the factory for approximately 25 feet of lineset; additional refrigerant must be added for longer runs per manufacturer specs.

Question 3

Which type of copper tubing is required for ACR (Air Conditioning and Refrigeration) refrigerant line sets?

Accepted Answer

Dehydrated, nitrogen-charged ACR copper tubing

Answer

ACR-grade copper tubing is cleaned, dehydrated, and sealed with nitrogen to prevent moisture and contamination that would damage refrigerant systems.

Question 4

When insulating suction line tubing on an AC installation, the insulation must be:

Accepted Answer

Continuous with no gaps, joints sealed, and of adequate wall thickness

Answer

Suction line insulation must be continuous and fully sealed to prevent condensation, heat gain, and capacity loss throughout the entire lineset run.

Question 5

What is the primary reason technicians perform a nitrogen pressure test before evacuating a new AC system?

Accepted Answer

To identify and locate leaks before pulling a vacuum

Answer

Nitrogen pressure testing at 150–300 psig reveals leaks at joints and connections before the vacuum process, since a vacuum cannot identify leak locations.

Air Conditioning Repair Practice Test

Air Conditioning Repair Practice Test

Air Conditioning Repair Installation and Evacuation Procedures 3