Industry Best Practices Flashcards

What is the main purpose of low-loss fittings on hoses?

Answer: To minimize refrigerant release when hoses are disconnected

Low-loss fittings close automatically or manually, which traps refrigerant in the hose when it's disconnected.

Which instrument should be used to accurately confirm a deep evacuation level?

Answer: Electronic micron gauge

Compound gauges can't read low vacuums accurately, but a micron gauge measures them precisely.

A system is heavily contaminated with moisture. What evacuation technique is recommended?

Answer: Triple evacuation, breaking the vacuum with dry nitrogen between pulls

Breaking the vacuum with dry nitrogen absorbs and sweeps out moisture, so repeated pulls dry the system more effectively.

Why might a technician heat the compressor crankcase during recovery?

Answer: To release refrigerant dissolved in the oil

Refrigerant dissolves in compressor oil, and gentle heat drives it out so more can be recovered.

An electronic leak detector shows a leak in a general area. What is the best way to pinpoint the exact location?

Answer: Apply a soap bubble solution

Bubble solution forms visible bubbles at the exact point where gas escapes.

Why should zeotropic blends such as R-404A or R-407C be charged as a liquid?

Answer: To prevent fractionation and keep the blend's composition correct

Zeotropic blend components boil at different temperatures, so vapor charging changes the mix that goes into the system.

When charging liquid blend into the suction side of an operating system, what is the best practice?

Answer: Meter or throttle the liquid so it vaporizes before reaching the compressor

Throttling the liquid keeps liquid refrigerant from slugging the compressor and damaging the valves.