NATE HVAC case studies
NATE HVAC · Put your knowledge to work in context.
NATE certification is a professional credential for heating, ventilation, air conditioning and refrigeration (HVACR) technicians. NATE describes itself as the nation's largest nonprofit certification organization for HVACR technicians, and its credentials are used by contractors who want a verifiable, third-party signal of a technician's competence rather than a self-reported resume line. The NATE HVAC case studies are 5 cases and about 3,858 words.
1Nonstop Runtime at 95°F: Undercharge, Restriction, or Overcharge?
A 3-ton R-410A split system with a TXV and a rated airflow of 1,200 cfm serves a second-floor zone. On a 95°F day the homeowner says the unit runs nonstop and the house will not drop below 78°F, though the design indoor temperature is 75°F.
756 words, about 4 min2100,000 BTU Furnace at 0.9 in. w.c. Static and 74°F Rise
A 100,000 BTU/h, 80% AFUE single-stage upflow furnace sits in a closet with a louvered door. Its rating plate lists a 35–65°F temperature rise and 0.5 in.
759 words, about 4 min3Auxiliary Heat Runs All Winter on a 28°F Day
An 1,800 sq ft house has a 3-ton, 15 SEER2 heat pump with a 10 kW electric strip kit and a three-stage thermostat. The homeowner complains that the auxiliary light is on most of the winter, the strips seem to run even at 45°F outdoors, and the January bill doubled.
786 words, about 4 min4Hot Master Bedroom, 95 cfm, and 0.85 in. w.c. of Static
An 1,800 sq ft ranch has a 3-ton system moving a nominal 1,200 cfm through a 20x8 trunk. Total external static reads 0.85 in.
747 words, about 4 min5Walk-In Freezer Icing Up With 8°F Product
A walk-in freezer, 8x10x8, holds ice cream at a setpoint of −10°F. It uses a remote air-cooled condensing unit with R-448A, an electric-defrost evaporator, a defrost time clock with a 30-minute fail-safe, and temperature-terminated defrost.
810 words, about 4 min