Piping, Brazing & Leak Detection Flashcards

Which refrigerant leak detection method offers the highest sensitivity, capable of detecting leaks as small as 0.1 oz per year?

Answer: Electronic refrigerant leak detector

Electronic leak detectors (heated diode, infrared, or heated pentode types) are capable of detecting trace levels of refrigerant far below the threshold of bubble or UV dye methods.

Under Canadian federal refrigerant regulations, technicians must repair leaks in systems with a refrigerant charge above what threshold within 30 days of detection?

Answer: Systems with a charge above 3 kg

Under Canada's Ozone-depleting Substances and Halocarbon Alternatives Regulations (CEPA), systems containing more than 3 kg of refrigerant must have detected leaks repaired within 30 days.

When pressure testing a refrigerant system, dry nitrogen is preferred over refrigerant because:

Answer: Nitrogen is inert, non-toxic, non-flammable, and leaves no residue in the system

Dry nitrogen is the preferred test medium because it is inert, poses no environmental risk, carries no oil contamination risk, and does not condense at test temperatures.

UV dye leak detection requires which additional piece of equipment to be effective?

Answer: A UV (black light) lamp and UV-filtering safety glasses

UV fluorescent dye only becomes visible when illuminated by an ultraviolet (black light) lamp, and UV-filtering glasses enhance contrast to reveal even faint traces of dye.

A nitrogen standing pressure test is held at 200 psig. After 60 minutes the gauge reads 192 psig with no change in ambient temperature. What is the most likely explanation?

Answer: A leak exists somewhere in the system

Nitrogen does not condense or absorb into oil under normal conditions, so any measurable pressure drop during a standing test at constant temperature indicates a leak.

Which type of electronic leak detector is best suited for detecting leaks of HFO refrigerants such as R-1234yf?

Answer: Infrared (IR) sensor detector

Infrared sensor detectors identify refrigerant by molecular absorption at specific IR wavelengths and can detect a broad range of HFC and HFO refrigerants including R-1234yf.

After repairing a refrigerant system leak, what two steps are mandatory before recharging with refrigerant?

Answer: Perform a leak test, then evacuate the system to deep vacuum

A post-repair leak test confirms the repair is sound, and a deep vacuum evacuation removes air and moisture before refrigerant is introduced to prevent acid formation and system damage.