NATE Heat Pump Install study plan

Trace the vapor-compression cycle on a hand-drawn pressure-enthalpy diagram, labeling subcooling, superheat, and compression ratio for a heating-mode heat pump.

Identify the function and failure signature of each major component: compressor, reversing valve, expansion device, accumulator, suction line accumulator, and defrost control board.

Explain how a reversing valve swaps the evaporator and condenser roles between heating and cooling, including which line becomes the hot-gas discharge in defrost.

Describe the four charging methods (weigh-in, subcooling, superheat, approach) and state which applies to a TXV system versus a fixed-orifice system in heating and cooling.

List the nitrogen-flow brazing steps and the purpose of a flowing purge during joint assembly.

Perform a full evacuation on a training or shop system and record micron decay over a 10-minute standing vacuum test.

Calculate required additional charge from line-set length, liquid-line diameter, and manufacturer charge tables for two different brands.

Demonstrate a triple-evacuation or core-removal procedure and explain when each is appropriate.

Diagnose a simulated restricted metering device using superheat, subcooling, and pressure-drop readings.

Measure external static pressure across a coil and air handler with a manometer and convert readings to fan-curve airflow using the manufacturer table.

Calculate required airflow from nominal capacity using 400 CFM per ton and compare it to the measured value.

Lay out a duct system that meets manual D sizing, including return sizing and static budget, for a 3-ton system.

Explain how improper airflow distorts superheat and subcooling readings and can mimic a refrigerant charge fault.

Read a heat pump wiring diagram and identify line voltage, control voltage, defrost board, and auxiliary heat circuits.

Size conductors, overcurrent protection, and disconnect for a given nameplate MCA and MOP.

Wire a low-voltage thermostat with emergency heat and identify the function of R, C, O/B, W, Y, and G terminals.

State the lockout/tagout, PPE, and refrigerant handling requirements that apply to a residential heat pump service call.

Evaluate three outdoor unit locations against clearance, snow, wind, and recirculation criteria and score them.

Design a condensate and defrost drainage path that prevents ice buildup and water intrusion into the structure.

Specify mounting method (pad, wall bracket, roof curb) and vibration isolation for each of three installation scenarios.

Explain how snow-cover kits and risers affect defrost performance and airflow.

Perform a room-by-room load estimate using a manual J method for a sample house and document assumptions.

Select an indoor and outdoor match that meets the load and verify the AHRI match and rated capacity at design temperature.

Build a commissioning checklist covering charge verification, airflow, temperature split, and defrost initiation test.

Calculate heating capacity balance point and explain how auxiliary heat staging covers the deficit.

Run a full start-up on a shop system and record superheat, subcooling, delta-T, static pressure, and amp draw against manufacturer targets.

Force a defrost cycle and verify termination, then document the defrost time/temperature settings.

Diagnose three injected faults (low charge, restricted filter drier, failed reversing valve) using a structured symptom-to-cause method.

Write a preventive maintenance task list with intervals for coils, drains, electrical connections, and refrigerant charge checks.

Complete a 60-question timed practice exam across all nine domains and score each domain separately.

Review every missed item and write a corrected explanation for each, citing the governing principle.

Re-drill the two lowest-scoring domains with targeted calculations and procedure walkthroughs.

Assemble a one-page reference card of formulas, key setpoints, and safety limits for final review.