AL HVAC study plan

Draw the vapor-compression cycle from memory, labeling all four state points with phase and relative pressure/temperature.

Explain in writing the function of the compressor, condenser, metering device, and evaporator, plus how each fails.

Calculate superheat and subcooling for three given operating scenarios and state whether charge is correct.

Compare reciprocating, scroll, screw, and centrifugal compressors by capacity range and typical application.

Classify the five most common metering devices (fixed orifice, TXV, EEV, capillary, AXV) by how each responds to load.

Trace the refrigerant path through a split system and state the correct location of filter drier, accumulator, receiver, sight glass, and muffler.

Distinguish ACR copper, plumbing copper, and approved fittings by wall thickness, marking, and permitted use.

Write the step-by-step brazing sequence including nitrogen purge, heat direction, alloy selection, and post-braze cleaning.

Select tubing diameter and equivalent length for three capacities using a manufacturer's line-sizing chart.

Describe proper flaring, swaging, and bending procedures and the faults each prevents.

Compare DX versus chilled-water systems and air-cooled versus water-cooled condensers by application and service implications.

Match indoor and outdoor design conditions to rated capacity using manufacturer performance tables.

Separate total capacity into sensible and latent components for three sets of entering-air conditions.

Diagnose a frosted evaporator by ranking likely causes from a supplied symptom list.

Explain how coil configuration, airflow direction, and metering device interact to set system balance.

Describe the combustion process and distinguish natural-draft, induced-draft, power-vent, and direct-vent appliances.

Sequence the ignition and operating steps of a gas furnace and name each safety switch and what it protects.

Explain reversing-valve operation and the defrost cycle in a heat pump, including the sensors and controls involved.

Calculate electric resistance heat kW, BTUH, and the CFM needed for a specified temperature rise.

Compare oil, gas, electric, and heat pump heating systems by efficiency metric (AFUE, COP, HSPF) and service requirements.

Read a ladder diagram and trace a complete control circuit from thermostat call to load energization.

Identify symbols for contacts, relays, transformers, capacitors, and safety devices and state each device's normal state.

Measure voltage, current, resistance, and microamps in simulated circuits and predict expected readings before measuring.

Differentiate PSC, ECM, and shaded-pole motors and describe the starting components and failure symptoms of each.

Explain the function of contactors, sequencers, defrost boards, and phase monitors in a typical system.

Perform a room-by-room heat loss and heat gain calculation using accepted residential load-calculation principles.

Size supply and return ductwork with the equal-friction method for a given CFM and layout.

Explain static pressure, duct velocity, and fitting losses, then build a static-pressure budget for the layout.

Apply ventilation and exhaust requirements, including fresh-air and exhaust-fan sizing for a dwelling.

Match equipment capacity to the calculated load and justify any oversizing or downsizing decision.

Write a startup and commissioning checklist covering evacuation, charging, airflow verification, and temperature split.

Describe evacuation to 500 microns and the standing-vacuum decay test, and state pass/fail criteria.

Verify charge targets for fixed-orifice and TXV systems using superheat or subcooling as appropriate.

Build a troubleshooting decision tree for no-cooling, low-capacity, and short-cycling complaints.

Diagnose electrical and airflow faults from a set of supplied gauge, meter, and temperature readings.

Apply refrigerant recovery, recycling, and reclamation rules, including venting prohibitions and leak-repair thresholds.

Distinguish ODP and GWP and classify common refrigerants by safety group and handling requirement.

Describe safe cylinder handling, PPE, ventilation, and confined-space precautions for refrigerant work.

Explain nitrogen pressure testing, regulator use, and why oxygen or air must never be used for leak testing.

Re-solve mixed problems from the refrigeration and troubleshooting domains under timed conditions.