NATE HVAC study guide
NATE HVAC · Work through your exam, one topic at a time.
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 study guide has 10 sections and about 2,818 words.
01Core: Safety, Tools, and Refrigeration/Electrical Fundamentals
Start with the hazards: lockout/tagout before opening any disconnect, PPE (goggles, gloves, insulated tools), and refrigerant handling under EPA Section 608. Refrigerant vapor is heavier than air and displaces oxygen in pits and basements; liquid refrigerant causes frostbite; never pressurize a system with oxygen or compressed air.
297 words, about 1 min02Air Conditioning: Charging and Diagnosing the Cooling Cycle
You must move fluidly between pressures and temperatures. Convert suction pressure to evaporating saturation temperature and liquid-line pressure to condensing temperature, then compute superheat (suction line temperature minus evaporating temperature) and subcooling (condensing temperature minus liquid line temperature).
272 words, about 1 min03Air Distribution: Airflow, Static Pressure and Proven Numbers
Air distribution questions test whether you can prove airflow rather than guess at it. Know total external static pressure (TESP): measure with a manometer using the correct pressure taps, with a clean filter and a wet coil, and compare the result to the blower performance table.
305 words, about 2 min04Gas Heating: Combustion, Pressures and the Safety Chain
Gas heat questions center on combustion and the sequence of operation. Know the sequence: call for heat, inducer proves draft through the pressure switch, the ignition source energizes, the gas valve opens, flame proves through the flame sensor, the blower starts on a time/temperature delay, and the high limit protects the heat exchanger.
287 words, about 1 min05Heat Pump: Reversing the Cycle and Auxiliary Heat
A heat pump adds a reversing valve, so the outdoor coil becomes the evaporator in heating and the indoor coil becomes the condenser. Know which coil is which in each mode, that the suction line is always the line returning to the compressor (measured at the true suction port on the reversing valve), and that the indoor coil rejects heat in the heating mode.
289 words, about 1 min06Oil Heating: Nozzles, Pressure and Combustion Testing
Oil heat questions revolve around the burner's hydraulic and electrical parts. Know the sequence: thermostat calls, the primary control starts the burner motor and ignition transformer, the fuel unit builds pressure (typically 100 psi, sometimes 140 psi), the nozzle atomizes oil, the electrodes ignite the spray, and the cad cell proves flame to hold the control in.
278 words, about 1 min07Hydronics (Gas and Oil): Pressure, Circulation and Air Control
Hydronic questions test the relationship between pressure, temperature and air. Know the fill pressure: about 1 psi per 2.31 ft of height above the fill point plus 4-5 psi, so a two-story house typically fills cold at around 12 psi.
277 words, about 1 min08Light Commercial Air Conditioning: Rooftops, Three-Phase Power, Economizers
Light commercial cooling adds scale and controls: packaged rooftop units, split systems with remote condensing units, two-stage or tandem compressors, belt-driven blowers, VAV boxes and economizers. Know three-phase basics: 208/230 V and 460 V systems, line versus control voltage, phase rotation and phase loss, contactors, overloads, and crankcase heaters.
268 words, about 1 min09Commercial Refrigeration: Low and Medium Temperature Systems
Commercial refrigeration runs continuously at low or medium temperature, so controls and accessories differ from comfort cooling. Know the components: condensing unit, receiver, liquid line with filter-drier and sight glass, TEV, evaporator (unit cooler), suction line with accumulator or heat exchanger, and head-pressure controls for low ambient (fan cycling, fan speed, or flooded condenser holding minimum receiver pressure).
268 words, about 1 min10Light Commercial Refrigeration: Walk-ins, Reach-ins and Ice Machines
This domain applies refrigeration fundamentals to equipment you can touch: walk-in coolers and freezers, reach-in cases, prep tables and ice machines. Know the differences.
277 words, about 1 min