AL HVAC study guide
AL HVAC · Work through your exam, one topic at a time.
The Alabama HVAC Contractor Licensing Examination is the qualifying exam used by the state's licensing authority to evaluate whether an applicant has the technical and business knowledge expected of a heating, air conditioning, and refrigeration contractor. It is intended for people seeking contractor-level licensure - typically experienced technicians, business owners, and installers moving from hands-on trade work into company-level responsibility - rather than for apprentice certification. The AL HVAC study guide has 10 sections and about 3,103 words.
01Refrigeration Principles and System Components
Refrigeration removes heat from a space and rejects it outdoors; it never "adds cold." Candidates must be fluent with the pressure–temperature (P–T) chart: for any refrigerant, saturation temperature corresponds exactly to pressure, so gauges are the fastest way to know what the refrigerant is doing. Know the four components and their jobs - compressor (raises pressure and temperature, moves mass flow), condenser (rejects sensible and latent heat, producing subcooled liquid), metering device (drops pressure, creating a flash-gas mixture), and evaporator (absorbs heat, producing superheated vapor).
323 words, about 2 min02Heating Systems (Gas, Oil, Electric, and Heat Pumps)
Combustion requires fuel, oxygen, and ignition in the right ratio. Natural gas manifold pressure is typically 3.5 in.
322 words, about 2 min03Air Conditioning and Cooling Equipment
Split systems pair an outdoor condensing unit with an indoor coil; packaged units contain everything in one cabinet. Know SEER2 (seasonal efficiency), EER2 (peak-load efficiency), and that ratings assume matched components and specific airflow.
319 words, about 2 min04Electrical Systems, Motors, and Controls
Ohm's law (V = I × R) and the power equation (W = V × A, or I²R) drive almost every electrical question. In series circuits, current is common and voltages add; in parallel circuits, voltage is common and currents add.
295 words, about 1 min05Ductwork, Air Distribution, and Ventilation
The blower moves air because it creates a pressure difference. Total external static pressure (TESP) is measured across the equipment - return static plus supply static - and is compared to the blower performance table.
290 words, about 1 min06Piping, Tubing, Fittings, and Brazing
Know copper types K, L, and M (wall thickness decreases in that order) and ACR tubing, which is cleaned and capped and is standard for refrigeration. Line sizing balances pressure drop against oil return: oversized suction lines lose oil return, undersized lines lose capacity.
321 words, about 2 min07Load Calculation and System Design
Load calculation estimates how much heat a building gains or loses under design conditions. Conduction through assemblies uses Q = U × A × ΔT, where U = 1/R.
321 words, about 2 min08Installation, Testing, and Commissioning
Correct installation starts with the manufacturer's instructions, proper clearances, a level pad or bracket, vibration isolation, and correctly sized and routed line sets. Protect the suction line, slope condensate drains with a trap where required, and keep service access clear.
319 words, about 2 min09Service, Maintenance, and Troubleshooting
Good troubleshooting is a sequence, not a guess: gather the complaint, verify the symptom, check the simple things (thermostat mode, filter, breaker, disconnect), then measure airflow, electrical values, and refrigerant pressures. Compare superheat, subcooling, temperature split, and amp draw against expectations.
278 words, about 1 min10Safety, Environmental Regulation, and Refrigerant Handling
Anyone who maintains, services, repairs, or disposes of appliances containing ozone-depleting refrigerants or their substitutes must hold EPA Section 608 certification: Type I (small appliances), Type II (high-pressure systems, including most residential splits), Type III (low-pressure chillers), or Universal. Intentional venting is prohibited.
315 words, about 2 min