Leak Detection and Repair Procedures Flashcards

A technician needs to pressurize an empty system to locate a leak. Which gas is the preferred choice for pressurizing?

Answer: Dry nitrogen

Dry nitrogen is inert and moisture-free, making it the safe, standard gas for pressure-testing refrigeration systems.

Why must oxygen never be used to pressurize a refrigeration system for leak testing?

Answer: It mixes with compressor oil and can cause an explosion

Oxygen in contact with oil under pressure can ignite violently and explode.

When using a nitrogen cylinder to pressure-test a system, which equipment is required between the cylinder and the system?

Answer: A pressure regulator and a pressure relief valve

Nitrogen cylinders hold over 2,000 psig, so a regulator and relief valve prevent overpressurizing the system.

Which leak-detection method is generally considered the most precise for pinpointing the exact location of a small leak?

Answer: Soap bubble solution

Bubble solution applied directly to a suspected joint shows the precise point where gas escapes.

A halide torch will NOT detect leaks of which refrigerant?

Answer: HFC-134a

Halide torches react to chlorine, and HFC-134a contains no chlorine.

Because most refrigerants are heavier than air, where should an electronic leak detector probe be positioned when searching a joint?

Answer: Slightly below the suspected leak point

Heavier-than-air refrigerant vapor tends to fall, so sampling below the joint improves detection.

A technician notices an oily residue on a flare fitting in a refrigeration circuit. What does this most likely indicate?

Answer: A refrigerant leak at that fitting

Refrigerant carries compressor oil through the system, so oil spots often mark a leak point.