HVAC Excellence study plan

Trace the four state points of the vapor-compression cycle on a pressure-enthalpy sketch and label the phase at each point.

Compute superheat and subcooling from suction-line and liquid-line temperatures paired with gauge pressures given in a practice problem set.

Distinguish the function of the compressor, metering device, evaporator, and condenser by the pressure change and heat-transfer direction each produces.

Explain in your own words why a restricted metering device raises superheat and lowers suction pressure.

Sequence the leak-test, evacuation, recovery, and charging steps for a residential split system and state a pass/fail criterion for each step.

Classify six common refrigerant blends by ASHRAE safety group and by whether they are zeotropic, and note the charging consequence of glide.

Interpret standing-vacuum decay and micron-level readings to decide whether a system is dry and tight.

State the rules for cylinder fill limits, recovery of different refrigerant types, and required handling records.

Read a ladder diagram for a residential blower and furnace circuit and separate the line-voltage path from the low-voltage path.

Measure and interpret resistance across a run capacitor, a start winding, and a contactor coil given sample meter readings.

Compute full-load amps, minimum conductor ampacity, and breaker size from a nameplate using Ohm's law and the 125% continuous-load rule.

Diagnose an open winding, a shorted capacitor, and a welded contactor from a table of ohm and volt readings.

Describe the sequence of operation for a heat pump in normal heating, defrost, and auxiliary heat modes.

Convert a 4-20 mA and a 0-10 V sensor signal into an engineering reading, and state what an open or shorted sensor reports.

Explain how time delays, safety switches, and lockout logic appear on a control board and which fault each produces.

Match six thermostat and control settings to the system behavior they change.

Calculate steady-state efficiency from stack temperature, ambient temperature, and CO2 using the flue-loss method.

Order the ignition sequence for standing-pilot, intermittent-pilot, and direct-spark ignition systems.

Diagnose the four common causes of a rollout switch trip and name the test that isolates each cause.

Convert manifold gas pressure to expected input rate and compare it against the nameplate derated value.

Trace the airflow path and build a pressure-drop budget across the filter, coil, supply duct, and return duct.

Compute total external static pressure from sample manometer readings and locate the operating point on a fan curve.

Solve the sensible heat equation (Qs = 1.08 x CFM x delta-T) for CFM, delta-T, and sensible capacity in turn.

Explain draft, spillage, and combustion air requirements for a Category I appliance and what field condition causes each to fail.

Describe the setup and procedure for a duct leakage test and judge sample CFM25 results against a stated program threshold.

Select and interpret the right envelope metric among CFM50, ACH50, and leakage per unit envelope area for a given building description.

Choose between superheat, subcooling, and approach charging methods for fixed-orifice versus TXV systems and justify the choice.

Diagnose low airflow, overcharge, and a restricted filter from a table of simultaneous dry-bulb, wet-bulb, superheat, and static pressure readings.

Assemble a single one-page reference sheet of formulas, conversions, and safety limits recalled without notes.

Complete two timed 50-question mixed practice sets and rank every miss by domain.

Re-teach your two weakest domains from memory in a five-minute written or recorded explanation.

Re-run every earlier week's deliverable and log pass or fail on each one.