West Virginia Heating, Ventilating and Cooling Contractor Examination

A West Virginia Heating, Ventilating and Cooling Contractor license, as defined in the Prov WVCLB bulletin, authorizes contracting to install, erect, repair, service, or alter which systems?

• AOnly residential window air conditioners under 1 ton
• BHeating, ventilating, and air-conditioning equipment or systems for residential and comme…
• COnly Division of Labor HVAC Technician service work on existing systems
• DPlumbing drain, waste, and vent systems exclusive of HVAC

One ton of refrigeration capacity is equal to which heat-removal rate?

• A8,000 Btu/h
• B10,000 Btu/h
• C12,000 Btu/h
• D15,000 Btu/h

In the vapor-compression refrigeration cycle, heat is rejected from the refrigerant in which component?

• AThe evaporator
• BThe metering device
• CThe compressor crankcase heater
• DThe condenser

Superheat is best defined as:

• AThe temperature of liquid refrigerant below its condensing saturation temperature
• BThe temperature of refrigerant vapor above its evaporating saturation temperature
• CThe difference between indoor wet-bulb and dry-bulb temperatures
• DThe outdoor design dry-bulb minus indoor design dry-bulb

Subcooling is best defined as:

• AThe temperature of liquid refrigerant below its condensing saturation temperature
• BThe temperature of suction vapor above evaporator saturation temperature
• CThe indoor-outdoor temperature difference used in Manual J
• DThe temperature drop across a cooling coil only

Sensible heat is heat that:

• AChanges the moisture content of air without changing dry-bulb temperature
• BChanges dry-bulb temperature without a change of state
• CIs released only when refrigerant condenses
• DExists only in hydronic systems

Using Qs = 1.08 × CFM × ΔT, what supply airflow is required to deliver 32,400 Btu/h of sensible cooling with a 20°F air-side temperature drop?

• A1,000 CFM
• B1,200 CFM
• C1,500 CFM
• D1,800 CFM

Wet-bulb temperature is the better single-air-property indicator of which quantity?

• ADuct velocity
• BRefrigerant subcooling
• CTotal heat content (enthalpy) of moist air
• DManifold gas pressure

Condensation forms on a cold supply duct when the duct surface temperature is:

• AAbove the dew-point temperature of the surrounding air
• BEqual to the refrigerant saturation temperature only
• CBelow the dew-point temperature of the surrounding air
• DAbove the indoor dry-bulb temperature

Heat flow through a wall by conduction is calculated with which relationship?

• AQ = U × A × ΔT
• BQ = 1.08 × CFM × ΔT only, with no area term
• CQ = 0.68 × CFM × grains difference
• DQ = 500 × GPM × ΔT

A Category IV gas-fired condensing furnace is characterized by which venting condition?

• ANon-positive vent pressure and a vent temperature high enough to avoid condensation in th…
• BPositive vent pressure and a vent gas temperature that can cause condensation in the vent
• CNatural-draft Type B double-wall vent only, with no condensate drain
• DAn unvented decorative appliance listing

A fan-assisted Category I furnace typically requires which vent material family?

• AListed Type B gas vent or another vent listed for Category I negative-pressure, non-conde…
• BSchedule 40 PVC because all modern furnaces are condensing
• CSingle-wall connector and masonry chimney with no lining, regardless of listing
• DFlexible dryer foil duct

A typical atmospheric natural-gas furnace is adjusted for a manifold pressure of about:

• A3.5 inches water column
• B11 inches water column
• C14.7 psig
• D2 psig at the burner orifices

A typical propane (LP) atmospheric furnace manifold pressure is about:

• A3.5 inches water column
• B7 inches water column
• C11 inches water column
• D11 psig

Carbon monoxide in furnace flue gas is primarily a product of:

• AComplete combustion with excess air
• BIncomplete combustion caused by lack of air, flame impingement, or a cracked heat exchang…
• CSensible heat removed at the evaporator
• DToo much subcooling in the liquid line

While brazing copper refrigerant tubing, dry nitrogen should be flowed through the pipe in order to:

• AIncrease the brazing alloy melting temperature
• BPrevent copper oxide scale from forming on the interior wall
• CPressurize the system to operating charge pressure
• DReplace the need for a filter-drier

Under EPA Section 608 terminology, reclaiming refrigerant means:

• ARemoving refrigerant from a system and putting it back into the same system without clean…
• BCleaning refrigerant on site for immediate reuse in any system
• CProcessing recovered refrigerant to AHRI 700 purity specifications, typically off site, w…
• DVenting refrigerant to atmosphere after a leak

Compared with R-22, R-410A service pressures are:

• AAbout the same at the same saturation temperature
• BSignificantly higher at the same saturation temperature
• CSignificantly lower, so R-22 gauges may be used without concern
• DVacuum only, because R-410A is an ammonia blend

A deep vacuum commonly used to dehydrate a residential air-conditioning system is considered complete when the micron gauge, isolated from the pump, holds at about:

• A5,000 microns and rising rapidly
• B2,500 microns
• C500 microns or below and is stable
• D29 inches Hg on a manifold compound gauge only

Most residential HVAC control circuits operate at which nominal voltage?

• A12 VDC from the thermostat batteries only
• B24 VAC from a control transformer
• C120 VAC through the thermostat
• D480 VAC three-phase at the thermostat

A 40 VA, 24 VAC control transformer can continuously supply a maximum current of about:

• A0.17 A
• B1.7 A
• C4.0 A
• D40 A

A filter in a forced-air HVAC system is installed to:

• AIncrease furnace AFUE by adding heat
• BProtect the coil and blower from airborne particulate and improve delivered air cleanline…
• CReplace the need for outdoor combustion air
• DRaise duct velocity to SMACNA maximums

External static pressure (ESP) of a residential air handler is best described as:

• AThe refrigerant high-side pressure
• BThe total duct, coil, filter, and accessory pressure drop the blower must overcome outsid…
• CThe manifold gas pressure
• DIndoor relative humidity

Using Qt = 4.5 × CFM × Δh, what is the total cooling load of 1,200 CFM with an enthalpy difference of 6.0 Btu/lb between entering and leaving air?

• A8,100 Btu/h
• B21,600 Btu/h
• C32,400 Btu/h
• D43,200 Btu/h

In the cooling mode, the indoor coil functions as the:

• ACondenser
• BCompressor
• CEvaporator
• DCooling tower

A cooling system with a thermostatic expansion valve (TXV) is normally charged by:

• ASuperheat only, ignoring the liquid line
• BSubcooling, using the manufacturer’s target
• CSuction-line frost length
• DNameplate amps alone

Air leaving a typical cooling coil is both cooler and drier than the entering air. On a psychrometric chart this process is:

• ASensible heating only, moving horizontally to the right
• BHumidification only, moving vertically upward
• CCooling and dehumidification, moving down and to the left
• DEvaporative cooling along the wet-bulb line toward saturation with no moisture removed

AFUE for a furnace is a measure of:

• ASeasonal cooling efficiency
• BAnnual fuel utilization efficiency — the seasonal fraction of fuel energy delivered as he…
• CAirflow in CFM per ton
• DVent connector diameter

In a heat pump, the reversing valve’s purpose is to:

• AMeter liquid refrigerant into the evaporator
• BSwitch the indoor and outdoor coils between evaporator and condenser duty
• COpen the gas valve
• DBypass the filter-drier on every cycle

A heat pump defrost cycle is needed because:

• AThe indoor coil ices during cooling in dry weather
• BThe outdoor coil, acting as the evaporator in heating, can accumulate frost that blocks a…
• CThe compressor oil must be boiled off each hour
• DSubcooling must be reset to zero

Using the standard indoor combustion-air method of 50 cubic feet per 1,000 Btu/h of input, what minimum indoor volume is required for an 80,000 Btu/h furnace and a 40,000 Btu/h water heater sharing a space?

• A2,400 cubic feet
• B4,000 cubic feet
• C6,000 cubic feet
• D12,000 cubic feet

The hydronic heat-rate equation Q = 500 × GPM × ΔT uses 500 because it approximately equals:

• AThe specific heat of air times 60
• B8.33 lb/gal × 60 min/h × 1 Btu/lb·°F for water
• CThe latent heat of steam
• DOne ton of refrigeration

One British thermal unit (Btu) is approximately the heat required to:

• ARaise 1 pound of water 1°F
• BRaise 1 gallon of water 1°F
• CMelt 1 ton of ice in 1 hour
• DRaise 1 cubic foot of air 1°F

Propane vapor is heavier than air, while typical natural gas is lighter than air. That is because propane’s specific gravity (air = 1.0) is about:

• A0.08
• B0.60
• C1.00
• D1.5

Using Ql = 0.68 × CFM × Δgrains, what is the latent load of 1,000 CFM with a humidity-ratio difference of 30 grains/lb?

• A6,800 Btu/h
• B10,200 Btu/h
• C20,400 Btu/h
• D30,000 Btu/h

POE (polyolester) oil used with HFC refrigerants such as R-410A is especially sensitive to:

• AMoisture contamination
• BNitrogen used as a brazing purge
• CCopper tubing
• DFilter-driers

IMC requires appliances, equipment, and materials to be installed in accordance with their listing and the manufacturer’s instructions. “Listed” means:

• AThe contractor wrote the model number on the permit
• BAn approved agency has evaluated the product to a consensus standard and identified it in…
• CThe product was purchased from a wholesaler
• DThe product is mentioned in a blog review

SEER (or SEER2) rates a central air conditioner or heat pump’s:

• AHeating-only AFUE
• BSeasonal cooling efficiency — cooling output over a cooling season divided by electrical…
• CHydronic pump horsepower
• DVent connector rise

ACCA Manual J default indoor cooling design conditions are:

• A70°F dry-bulb and 30% RH
• B75°F dry-bulb and 50% RH
• C78°F dry-bulb and 60% RH
• D72°F dry-bulb and 40% RH

If indoor heating design is 70°F and the outdoor 99% heating design dry-bulb used for the job is 5°F, the heating design temperature difference is:

• A65°F
• B70°F
• C75°F
• D5°F

For a typical single-zone central system serving one house, Manual J equipment selection should be based on:

• AThe block (whole-house) load at the design hour
• BThe sum of all peak room loads regardless of time of day
• CThe largest single bedroom load only
• DThe outdoor unit nameplate tons with no load calculation

A wall has U = 0.08 Btu/h·ft²·°F, net area 250 ft², and a heating ΔT of 65°F. What is the conductive heating load of that wall?

• A1,040 Btu/h
• B1,300 Btu/h
• C2,000 Btu/h
• D16,250 Btu/h

A house has a Manual J sensible cooling load of 21,600 Btu/h. Using CFM = Qs / (1.08 × ΔT) and a 20°F supply-air temperature difference, the required cooling airflow is:

• A800 CFM
• B1,000 CFM
• C1,200 CFM
• D1,600 CFM

A 12,000 ft³ house is assigned 0.35 air changes per hour for infiltration. What is the infiltration airflow?

• A35 CFM
• B70 CFM
• C120 CFM
• D210 CFM