System Installation and Brazing Flashcards

When using an oxyacetylene torch for brazing refrigerant lines, the flame should be adjusted to a:

Answer: Neutral flame

A neutral flame provides the correct heat balance for brazing copper without introducing excess oxygen or carbon to the joint.

What is the maximum recommended length of an unsupported horizontal refrigerant line run before a support hanger is required?

Answer: 5 feet

Refrigerant lines should be supported at least every 5 feet horizontally to prevent sagging, vibration damage, and stress on joints.

Before making a brazed joint on an existing system, the technician must first:

Answer: Recover all refrigerant from the system

Federal regulations require all refrigerant to be recovered before any brazing or repair that opens the refrigerant circuit.

Which type of copper tubing is approved for use in refrigerant line sets for residential AC systems?

Answer: ACR (Air Conditioning and Refrigeration) grade copper

ACR-grade copper tubing is cleaned, dehydrated, and capped at the factory, making it suitable for refrigerant service.

When routing refrigerant lines through a wall or floor, the technician should:

Answer: Install a protective sleeve or grommet to prevent abrasion

A sleeve or grommet protects the refrigerant lines from abrasion against sharp edges, which can cause premature leaks.

The suction line in a residential split system is typically insulated to:

Answer: Prevent condensation and maintain superheat entering the compressor

Insulating the suction line prevents heat gain from the ambient air, which could cause excessive superheat and reduce system efficiency.

After completing all brazed connections on a new installation, the next step before charging with refrigerant should be:

Answer: Pressure-test the system with dry nitrogen and check for leaks

Pressure-testing with dry nitrogen to the manufacturer's specified test pressure and leak-checking all joints is required before evacuation and charging.