Installation & Maintenance Practices Flashcards

A technician discovers a refrigerant leak at a flare fitting during a maintenance visit. What is the correct corrective action?

Answer: Cut off the flare and remake it, then re-tighten

Flare fittings that leak are usually deformed; the proper fix is to cut off the old flare and create a new one, then reassemble correctly.

What maintenance task should be performed on evaporator coil drain pans to prevent biological growth and drain blockage?

Answer: Add biocide tablets or clean and treat the pan and drain with approved algaecide

Biocide tablets or algaecide treatments prevent algae, mold, and slime from blocking condensate drains and creating health hazards.

During a preventive maintenance visit on a walk-in cooler, the technician measures a high condensing temperature. Which maintenance item is MOST likely the root cause?

Answer: Dirty or blocked condenser coil

A dirty or blocked condenser coil reduces heat rejection, directly raising condensing temperature and system head pressure.

What is the correct method for leak-checking a refrigeration system with an electronic leak detector?

Answer: Hold the probe below joints since refrigerant is heavier than air, then move slowly

Most refrigerants are heavier than air and collect at low points, so positioning the probe below fittings and moving slowly maximizes detection sensitivity.

An evaporator coil is completely encased in ice despite the refrigeration system running. After defrosting, what is the FIRST diagnostic step?

Answer: Check airflow across the evaporator for obstructions or failed fans

Restricted airflow is the most common cause of evaporator ice-over and must be verified before assuming a refrigerant or control problem.

When replacing a hermetic compressor, why must the system be thoroughly flushed if the previous compressor experienced a burnout?

Answer: To eliminate acid and carbon deposits that remain after a burnout

Acid and carbon contaminants from a compressor burnout remain in the system and will damage a replacement compressor if not removed by flushing and filter-drier replacement.

What is the purpose of installing a sight glass with a moisture indicator in a refrigeration liquid line?

Answer: Detect refrigerant bubbles indicating undercharge and monitor moisture content

A sight glass allows technicians to observe bubbling (indicating undercharge or flash gas) and the color-change indicator alerts them to moisture in the system.