Exam Cheat Sheet · Quick Reference
West Virginia HVAC Contractor
West Virginia · Prov
Verified, not estimated. Every figure below is drawn from the official exam structure we maintain — question counts, passing standard and topic weighting. Practice questions are grounded in the source law with statute citations. We omit any figure we can't verify rather than guess at it.
Total questions
80
Passing score
70%
Exam time
180 min
Administered by
Prov
Format
Reference materials allowed
West Virginia State Portion 80 questions
General Knowledge
30 Q · 38%
HVAC equipment selection and sizing (furnaces, air conditioners, heat pumps, boilers)Air distribution system design and duct sizingCopper and plastic piping identification, joining methods, and applicationsCarbon steel pipe types, fittings, threading, and joining methodsIMC definitions and general installation regulations for mechanical equipmentEnergy efficiency ratings (COP, EER, SEER, HSPF) and sustainability objectivesHydronic system basics and ducted air system fundamentalsChapter 7 - Heating and Cooling System DesignChapter 4 - Air Distribution SystemsChapter 2 - Basic Copper and Plastic Piping PracticesHVAC EquipmentChapter 3 - Basic Carbon Steel Piping Practices
+2 more
Load Calculations
6 Q · 8%
Heat transfer mechanisms (conduction, convection, radiation) and their role in building heat gain and lossIndoor and outdoor design conditions (design temperatures, daily range, humidity, design temperature difference)Heating load factors (walls, roofs, ceilings, floors, windows, doors, below-grade surfaces, infiltration, duct losses)Cooling load factors (solar gain through glass, internal gains from people and appliances, latent loads, infiltration)Equipment sizing based on calculated sensible and latent loads (cooling and heating equipment selection criteria)Building survey and data collection for load estimation (construction materials, orientation, insulation R-values, fenestration)Chapter 7 - Heating and Cooling System Design
Code Requirements
4 Q · 5%
Permits, inspections, and code enforcement authorityEquipment and appliance installation requirements (listing, labeling, clearances, location)Mechanical ventilation rates and outdoor air requirements by occupancyExhaust system discharge location and minimum separation distancesClothes dryer exhaust duct requirements (materials, length, termination)Commercial and domestic kitchen exhaust hood requirementsChimney and vent connector installation and termination requirementsCondensate disposal and auxiliary drain system requirements
Controls
10 Q · 12%
Thermostat types and functions (programmable, heat pump, setback)Thermostat location and mounting requirementsHumidity control devices and humidistat operationZoning systems and zone control strategies (single-zone, multi-zone, VVT, VAV)Control wiring requirements (low-voltage, disconnect provisions, grounding)Energy management and demand control strategiesFactory-installed versus field-installed controlsHome automation system integration and HVAC control interfacesChapter 7 - Heating and Cooling System DesignChapter 5 - Commercial Airside SystemsHVAC Equipment
Ducting, Insulation
10 Q · 12%
Duct materials (sheet metal, fiberglass ductboard, flexible duct, nonmetallic)Duct system layouts (perimeter-loop, radial, extended-plenum, reducing-trunk)Duct sizing and airflow calculations (CFM, velocity, static pressure, equivalent length)Duct sealing requirements and methods (mastic, UL 181 tapes, joint and seam sealing)Duct insulation and vapor retarders (R-value, duct wrap, duct liner, condensation prevention)Fire and smoke dampers (ratings, actuation, locations, access requirements)Registers, grilles, and diffusers (types, selection, placement, volume dampers, floor register load ratings)Flexible duct installation (support intervals, bend radius, length limits, connections)
Piping
6 Q · 8%
Copper tubing types, sizes, and identifying markings (Types K, L, M, ACR, DWV)Copper tube fittings and joining methods (flare, compression, sweat, swaged, pressed)Cutting, bending, and preparing copper tubing for installationPlastic piping types and joining methods (PVC, CPVC, ABS, PEX, PE) including solvent-cementing proceduresCarbon steel pipe types, fittings, threading, and joining methods (threaded, grooved, flanged)Hydronic piping materials, joint types, and installation requirements per IMC Chapter 12Pipe hangers, supports, and spacing requirements for copper, plastic, and steel pipeFuel oil piping materials, joints, valves, and system installation requirements per IMC Chapter 13Chapter 2 - Basic Copper and Plastic Piping Practices
Safety - OSHA
5 Q · 6%
OSHA Fatal Four hazards (falls, struck-by, caught-in/between, electrical)Fall protection systems (harnesses, lanyards, anchor points, guardrails, safety nets)Ladder safety (types, inspection, setup angles, three-point contact)Scaffold safety (types, tagging system, inspection, weight limits)Lockout/tagout (LOTO) procedures for energy controlPersonal protective equipment (PPE) selection, inspection, and useElectrical safety (grounding, GFCI, safe working distances, shock response)Hazard recognition, communication, and Safety Data Sheets (SDS/HAZCOM)Chapter 1 - Basic Safety (Construction Site Safety Orientation)
Equipment
9 Q · 11%
Heating equipment sizing and selection (furnaces, boilers, heat pumps)Cooling equipment sizing and selection (air conditioners, heat pumps)Boiler installation requirements, safety controls, and pressure relief devicesRefrigeration system classification, refrigerant types, and machinery room requirementsCombustion principles and venting systems for fuel-burning appliancesCommercial and industrial refrigeration components (compressors, condensers, evaporators, accessories)Solar thermal system design, installation, and equipment requirementsEquipment commissioning, startup verification, and replacement considerations
Key Distinctions
Type L copper (nominal sizing)vsType ACR tubing (actual OD sizing)
Type ACR is identical in construction and dimension to Type L but is called out by actual outside diameter, which is 1/8 in. larger than the nominal size, so 1 in. Type L is ordered as 1-1/8 in. ACR.
HVAC Basics for Contractors, Chapter 2 — Basic Copper and Plastic Piping Practices, Sections 1.1.1 and 1.1.3 (Copper Tube Types / Copper Tube Sizing)ConductivityvsConductance
Conductivity is heat flow through one inch of a homogeneous material, while conductance is the Btuh heat flow through one square foot of the entire thickness of a nonhomogeneous material (concrete block, hollow clay tile, glass block) at a 1°F surface-to-surface temperature difference.
HVAC Basics for Contractors, Chapter 7 — Heating and Cooling System Design, Module 03407 Page 14Heat transfer multiplier (HTM, Manual J)vsGlass load factor (GLF, ASHRAE)
HTM is based on the projected indoor-to-outdoor temperature difference, whereas GLF is based solely on the design outdoor temperature; results are comparable but the factors differ.
HVAC Basics for Contractors, Chapter 7 — Heating and Cooling System Design, Module 03407 Page 16Flammable liquid/fuelvsCombustible liquid/fuel
A flammable liquid has a closed cup flash point below 100°F (38°C); a combustible liquid has a closed cup flash point at or above 100°F (38°C).
HVAC Basics for Contractors, Chapter 1 - Basic Safety (Construction Site Safety Orientation), Book Page 12Low-pressure boiler (2018 IMC)vsHigh-pressure boiler (2018 IMC)
Low-pressure boilers operate at pressures less than or equal to 15 psi for steam and 160 psi for water; high-pressure boilers operate at pressures exceeding those values.
IMC 2018 Chapter 2, Section 202Grooved pipe coupling makeupvsFlanged joint makeup
Grooved coupling nuts are tightened alternately and equally only until metal-to-metal contact at the angle bolt pads (no special torquing), while flanged joints must be tightened with a torque wrench in incremental steps following a set pattern.
HVAC Basics for Contractors, Chapter 3 — Sections 3.2.0 and 3.2.4 Installing Grooved Pipe Couplings (Module 03105, Pages 18 and 21)Cut groovingvsRoll grooving
Cut grooving removes slightly less than one-half the pipe wall and is intended for standard weight or heavier pipe (generally not lighter than Schedule 40), while lighter-wall pipe is roll grooved because roll grooving displaces metal rather than removing it.
HVAC Basics for Contractors, Chapter 3, Section 3.2.2 Cut Grooving (Book Page 19)Copper or copper-alloy pipe hanger spacingvsCopper or copper-alloy tubing hanger spacing
Per 2018 IMC Table 305.4 the maximum horizontal support spacing is 12 feet for copper or copper-alloy pipe but 8 feet for copper or copper-alloy tubing.
IMC 2018 Table 305.4Job safety analysis (JSA)vsTask safety analysis (TSA)
Both require identifying hazards and safeguards before work begins; the difference is the reporting form — a TSA typically uses a pre-printed, fill-in-the-blank checklist that some companies require workers to sign before starting work.
HVAC Basics for Contractors, Chapter 1 - Basic Safety (Construction Site Safety Orientation), Book Page 14Single-vane volume dampervsMulti-vane (multi-blade) volume damper
Single-vane dampers are generally used in branch ducts where total static pressure is less than 0.5 in. w.c.; multi-vane or multi-blade dampers are used where total static pressure exceeds 0.5 in. w.c.
HVAC Basics for Contractors, Chapter 7 — Section 4.3.5 Fittings and Pressure LossStandard full-size pitot tubevsPocket-sized pitot tube
The standard pitot tube is used in ducts 8 in. and larger and has eight equally spaced 0.04 in. static holes; the pocket-sized tube is best for ducts smaller than 8 in. and has four equally spaced static-pressure holes.
HVAC Basics for Contractors, Chapter 4 — Section 1.3.2 Pressure Measurement Instruments (Pages 12 to 13)Electric resistance heat as primary heat sourcevsHeat pump plus supplemental electric heaters
Electric resistance primary heating capacity shall not be less than the calculated load and shall not exceed it by more than 10 percent, while the combined heat pump plus supplemental electric heater capacity should not exceed 115 percent of the calculated heating load — two separate maximums.
HVAC Basics for Contractors, Chapter 7 — Heating and Cooling System Design, Module 03407 Page 30Key Terms
Low-heat appliance (residential appliance) — 2018 IMC IMC 2018 Chapter 2, Section 202
An appliance in which the products of combustion at the point of entrance to the flue under normal operating conditions have a temperature of 1,000°F (538°C) or less.
Brazed joint — 2018 IMC IMC 2018 Chapter 2, Section 202
A gas-tight joint obtained by joining metal parts with metallic mixtures or alloys that melt above 1,000°F (538°C) but lower than the melting temperature of the parts being joined.
Modular boiler — 2018 IMC IMC 2018 Chapter 2, Section 202
A steam or hot-water-heating assembly made up of individual boilers called modules, each module limited to a maximum input rating of 400,000 Btu/h gas, 3 gallons per hour oil, or 115 kW electric.
Standard air — 2018 IMC IMC 2018 Chapter 2, Section 202
Air at standard temperature and pressure, namely 70°F (21°C) and 29.92 inches of mercury (101.3 kPa).
Class IA flammable liquid — 2018 IMC IMC 2018 Chapter 2, Section 202
A liquid having a flash point below 73°F (23°C) and a boiling point below 100°F (38°C).
Combustible liquid — 2018 IMC IMC 2018 Chapter 2, Section 202
A liquid having a closed cup flash point at or above 100°F (38°C).
Concealed location — 2018 IMC IMC 2018 Chapter 2, Section 202
A location that cannot be accessed without damaging permanent parts of the building structure or finish surface; spaces above, below, or behind readily removable panels or doors are not considered concealed.
Medium-duty cooking appliance — 2018 IMC IMC 2018 Chapter 2, Section 202
Includes electric discrete element ranges (with or without oven), electric and gas hot-top ranges, electric and gas griddles, double-sided griddles, fryers, tilting skillets (braising pans), and rotisseries; open-burner gas ranges and gas under-fired broilers are heavy-duty instead.
Type II dry cleaning system — 2018 IMC IMC 2018 Chapter 2, Section 202 (Definitions), and 12
A dry cleaning system using Class II combustible liquid solvents, i.e., solvents with a closed cup flash point at or above 100°F and below 140°F (Type I uses Class I flammable solvents below 100°F; Type III uses Class III solvents 140°F and above).
Degree day Residential Comfort System Installation Standards (Eighth Edition), Glossary, Page G5
A value based on the difference between a day's mean outdoor temperature and 65°F (18°C), used for estimating seasonal fuel use.
Low voltage (HVAC controls) Residential Comfort System Installation Standards (Eighth Edition), Glossary, Page G11
An electrical control system with a power supply of 25 volts or less, as distinguished from line voltage, which refers to normal supply voltages, most often 120 or 240 volts.
Ak factor HVAC Basics for Contractors, Chapter 4 — Section 2.5.0 Diffusers, Registers, Grilles, and Dampers (Book Page 32)
The area factor assigned to a grille, register, or diffuser, representing the free area of the outlet in square feet, which is multiplied by average outlet velocity to find cfm.
Specific heat of air at standard conditions (Cp) Residential Comfort System Installation Standards (8th ed.), Glossary, Page G15
0.24 Btu/lb/°F for air (water is 1.00 Btu/lb/°F).
Flare fitting (Type ACR/copper tubing) NCCER Module 03103, Section 1.2.1
A common mechanical joining method for copper tubing that is rarely used today on tubing larger than 7/8 in. OD but is very common on smaller sizes, mainly for refrigerant lines on small refrigeration circuits and for connecting pressure controls on systems of all sizes.
Combustible fuel (NCCER basic safety) HVAC Basics for Contractors, Chapter 1 - Basic Safety (Construction Site Safety Orientation), Book Page 12
A fuel with a flash point at or above 100°F (38°C); a flammable fuel has a flash point below 100°F (38°C).
Dry-bulb economizer candidate location HVAC Basics for Contractors, Chapter 5 — Commercial Airside Systems, Section 4.3.1 Dry-Bulb Economizer (Module 03201, Page 37)
Because supply air to the space is normally 50°F to 60°F, any location with a significant number of operating hours below 55°F outdoor dry bulb is a good candidate for a dry-bulb economizer.
Formulas to Know
Minimum duct insulation R-value (ASHRAE Standard 90-80 method), calculated for both cooling and heating modes with the greater need governing
R = TD ÷ 15, where TD is the temperature difference between inside and outside the duct; example: 125°F attic − 55°F supply air = 70°F; 70 ÷ 15 = 4.67 ≈ R-4.7 (the source's own worked example uses a 120°F attic, giving R = 4.3)Duct air volume from a velocity traverse
cfm = duct area (ft²) × velocity (fpm); example: 24 in. × 10 in. = 240 in² ÷ 144 = 1.667 ft² × 720 fpm = 1,200 cfm; example: 18 in. × 12 in. = 1.5 ft² × 1,100 fpm = 1,650 cfmRequired supply airflow from sensible load
cfm = sensible load (Btuh) ÷ (1.08 × temperature difference); example: 8,640 ÷ (1.08 × 20) = 400 cfmFan laws for a re-speeded blower on an unchanged duct system
Law 1: cfm varies directly with rpm (new rpm = new cfm × existing rpm ÷ existing cfm); Law 2: static pressure varies with the square of the speed ratio (0.40 × (1,000/800)² = 0.625 in. w.c.); Law 3: horsepower varies with the cube of the speed ratio (0.5 × (1,000/800)³ ≈ 0.98 hp)Total external static pressure the blower must overcome (residential duct design)
Corrected friction for a run = design friction per 100 ft × (total equivalent length ÷ 100); total ESP = supply duct friction + diffuser loss + return duct friction + grille loss + losses for components not included in the fan rating; example: (200 ft × 0.0006 = 0.12 + 0.05) + (150 ft × 0.0005 = 0.075 + 0.05) + 0.25 = 0.545 in. w.c.Maximum heating equipment output capacity (ACCA equipment-selection guidelines)
Electric resistance as primary heat: not less than the calculated load and not exceeding it by more than 10% (30,000 × 1.10 = 33,000 Btuh). Heat pump plus supplemental electric heaters: combined capacity should not exceed 115% of the calculated heating load (48,000 × 1.15 = 55,200 Btuh)Refrigeration machinery room emergency exhaust airflow upon refrigerant detector actuation (other than ammonia systems, e.g., halocarbon)
Q = 100 × √G, where G is the design mass of refrigerant in pounds in the largest system, any part of which is located in the machinery room; example: 100 × √625 = 2,500 cfm (the 30 air changes per hour emergency rate applies only to ammonia systems)Hydronic piping hydrostatic test pressure (2018 IMC 1208.1)
Test at 1.5 × maximum system design pressure but not less than 100 psi, held not less than 15 minutes; example: 1.5 × 60 = 90 psi, so the 100 psi floor governsFire damper actuation device operating temperature (duct not part of a smoke control system)
Approximately normal duct operating temperature + 50°F, but not less than 160°F; example: 140 + 50 = 190°F (350°F is the maximum operating temperature permitted for dampers in a smoke control system)Mixing plenum air balance and mixed-air temperature
Total mixed cfm = sum of entering streams (3,000 return + 1,000 outdoor = 4,000 cfm); T_mix = (Return cfm × Return temp + Outdoor cfm × Outdoor temp) ÷ Total cfm = (3,000 × 60 + 1,000 × 92) ÷ 4,000 = 68.0°F; outdoor-air fraction = outdoor cfm ÷ total cfm = 1,000 ÷ 4,000 = 25%