MD HVAC study guide
MD HVAC · Work through your exam, one topic at a time.
The Maryland HVACR credential is a state license administered under the Maryland Department of Labor's Division of Occupational and Professional Licensing (DOPL), which lists Heating, Ventilation, Air Conditioning and Refrigeration (HVACR) among the boards and programs it oversees. The license is aimed at technicians and contractors who install, service and repair heating, cooling, ventilation and refrigeration equipment in Maryland and who must show they have met a standard of expertise before practicing. Candidates typically sit a multiple-choice licensing examination that spans five broad areas: refrigeration principles and system components; gas, oil, electric and hydronic heating; air distribution, ventilation and indoor air quality; electrical controls, motors and troubleshooting; and code, safety, installation practices and business/licensing requirements. Because the five areas are treated as equal-weight domains in most HVACR blueprints, a passing strategy has to be balanced - strong electrical troubleshooting will not offset a weak showing on refrigeration theory or code. The MD HVAC study guide has 5 sections and about 1,964 words.
01Refrigeration Principles and System Components
At any given pressure a pure refrigerant has exactly one saturation temperature, and a P-T chart converts between the two in either direction. Superheat is measured suction-line temperature minus the saturation temperature at suction pressure.
340 words, about 2 min02Heating Systems: Gas, Oil, Electric and Hydronic
Gas furnace questions usually test combustion basics and manifold pressure. Natural gas manifold pressure is typically 3.5 in.
320 words, about 2 min03Air Distribution, Ventilation and Indoor Air Quality
Sensible capacity moves with CFM = sensible BTUH / (1.08 x delta-T) for standard air. The constant 4.5 is used for total heat, and 0.68 appears in some altitude-adjusted sensible charts.
326 words, about 2 min04Electrical Controls, Motors and Troubleshooting
Control circuits are series strings: 24 volts from the transformer passes through the thermostat, every safety, and the load. Any open safety - high limit, rollout switch, pressure switch, auxiliary limit - kills the whole string, so voltage-drop testing across each device finds the culprit faster than guessing.
324 words, about 2 min05Code, Safety, Installation Practices and Business/Licensing Requirements
Mechanical installations fall under the International Mechanical Code and the International Residential Code. Gas piping follows the International Fuel Gas Code.
654 words, about 3 min