NATE LC Refrigeration case studies
NATE LC Refrigeration · Put your knowledge to work in context.
NATE Light Commercial Refrigeration (LC) is a specialty certification for HVACR technicians who service refrigeration equipment in settings such as restaurants, convenience stores, and small grocery or food-service operations. NATE describes itself as the nation's largest nonprofit certification organization for heating, ventilation, air conditioning and refrigeration technicians, and its exams are built around the knowledge and field skills technicians use on the job. The NATE LC Refrigeration case studies are 5 cases and about 2,473 words.
1Reused TEV After R-448A Condensing Unit Replacement
A supermarket service company replaces a failed 1.5 HP R-404A condensing unit serving an 8 ft x 10 ft x 8 ft walk-in cooler with a new R-448A unit. The new unit is rated 10,500 Btu/h at 25°F evaporator and 120°F condensing; the old unit was 9,000 Btu/h at the same conditions.
560 words, about 3 min2Vacuum Decay on a New Frozen-Food Walk-In
A crew installs a new 12 ft x 16 ft x 10 ft frozen-food walk-in with two unit coolers, a 3 HP R-448A condensing unit, and 80 ft of line set with a 25 ft vertical rise to a remote receiver. They nitrogen-purge during brazing and pressure-test at 300 psig for 24 hours with no drop.
496 words, about 2 min3One Iced Evaporator in a Four-Circuit Produce Cooler
A 20 ft x 30 ft x 10 ft produce cooler is served by four matched unit coolers, each with a 1-ton TEV and a 24 V solenoid. The controller runs four 20-minute off-cycle defrosts per day.
512 words, about 3 min4Compressor Burnout Cleanup Under Time Pressure
A 5 HP semi-hermetic R-404A compressor on a low-temperature warehouse freezer fails with a grounded motor. The oil is black and smells burnt, and an acid test of the oil shows high acidity.
449 words, about 2 min5Defrost Breaker Trip on a Single-Phase Freezer
A 208 V single-phase walk-in freezer has a 2 HP condensing unit with RLA 12.5 A, two 2,500 W defrost heaters, evaporator fans, and a 30 A two-pole breaker. The freezer runs normally in cooling, but the breaker trips about 8 minutes into defrost.
456 words, about 2 min