NATE GS Installation study plan

Explain how total external static pressure is built from supply and return duct losses, filter, coil, and grille resistance

Convert between cfm, velocity, and duct cross-sectional area for rectangular and round ducts using the continuity equation

Identify the components of a simple air distribution system: return grille, filter, blower, heat exchanger or coil, supply plenum, trunk, branches, and diffusers

Read a duct layout sketch and label each fitting that adds resistance (elbows, tees, transitions, takeoffs)

Size supply and return ducts for a given cfm using a target friction rate and velocity limit

Describe how blower performance curves shift with static pressure and predict airflow change when a filter loads

Trace the refrigeration cycle states (compressor discharge, condenser outlet, metering device inlet/outlet, evaporator outlet) and name the phase at each point

Relate evaporator airflow and coil condition to sensible heat ratio and supply air temperature split

Balance a simple system on paper: set dampers to hit design cfm in each branch and explain the order of adjustment

Measure static pressure with a manometer and interpret readings across filter, coil, and plenum

Identify the electrical components in an air handler circuit: contactor, sequencer, relay, capacitor, transformer, and blower motor

Read a ladder diagram and trace the call-for-cool sequence from thermostat to blower and outdoor unit

Calculate current, voltage, and resistance in series and parallel circuits with a meter, including start and run windings

Test a run capacitor and a compressor winding set for opens, shorts, and grounds, and state pass/fail criteria

Explain superheat and subcooling targets and how each shifts with load, airflow, and charge

Diagnose three charging scenarios (undercharge, overcharge, restricted metering device) from superheat, subcooling, and pressures

Lay out a refrigerant line set with correct sizing, trapping, and support spacing, and explain why each rule exists

Describe brazing procedure: nitrogen purge, flux use, heat direction, and leak testing steps

Assemble and seal duct joints and explain the purpose of mastic, tape, and mechanical fasteners

Explain the psychrometric relationships among dry bulb, wet bulb, relative humidity, and dew point and use them to find coil entering and leaving conditions

Identify the three pollutant pathways (combustion products, moisture, volatile organics) and the control strategy for each

Explain how filter MERV rating, pressure drop, and airflow interact, and select a filter for a stated application

Describe duct leakage testing and why return-side leakage in an unconditioned space matters

Explain combustion air requirements and how to verify adequate ventilation for a gas appliance

State lockout/tagout, PPE, and refrigerant handling requirements for common service tasks

Identify electrical code requirements for disconnects, grounding, bonding, and overcurrent protection at the unit

Explain clearance, venting, and condensate disposal requirements that affect installation layout

List the personal and environmental hazards of refrigerant exposure and the recovery steps required

Complete a timed set of mixed-domain practice questions and score each domain separately

Re-teach the three weakest topics aloud from memory without notes

Re-perform the static pressure, superheat, and airflow calculations under time pressure

Build a one-page formula and reference card covering the highest-frequency calculations