HVAC contractor exam test 7
How much heat is required to melt a 10 pound block of ice that is sitting at
32 degrees F into warm water given that the heating temperature is at 80
degrees F? - -1,920 Btu/h
- In many condensing unit applications, it is necessary to heat the
compressor to evaporate liquid refrigerant trapped in the oil. Many large
compressors for commercial applications are manufactured and equipped to
handle this situation using a _________? - -Crankcase heater
- Find the MINIMUM size chimney required: A fan assisted Category 1
appliance with an input rating of 55,000 Btu/h is to be vented with a single
wall connector into a masonry chimney that is 20 feet high with a 10 foot
lateral. - -It is not recommended that this appliance be connected tot his
chimney
- Given that a motor compressor has a 2" bore and a 3" stroke, what would
be the calculated piston displacement in cubic inches? - -9.42
- A grain is a unit of weight equal to ___________, used to indicate the amount
of moisture in the air. - -1/7000 lb
- When computing heat leakage for a building, the U-value for most types of
construction can be obtained from reference books. The unit of measure for
U-value is expressed in __________? - -Btu/sq-ft/deg.F/Hr
- Absolute zero temperature is the temperature at which all molecular
motion ceases at approximately _______degrees Fahrenheit. - --460 degrees
F
- What would be the calculated resistance of a circuits load, given that the
load draws a total current of 20 amperes, and the circuit source operating
voltage is 240 VAC? - -12.0
- A contractor is working with auxiliary drain pans in a secondary drain
system for an air conditioning system. How deep should these auxiliary drain
pans be, AT LEAST? - -1-1/2 inches
- The operation of the thermostatic expansion valve is controlled by the
temperature of the thermal expansion valve and the pressure in the
evaporator. Therefore, when does the needle valve in the refrigeration
system normally open? - -When the evaporator pressure is low and the
temperature is above normal
, - According to International fire code Fire Code, duct smoke detectors in
heating and AC systems must be connected to what? - -The building fire
alarm system
- Voltmeters are always connected in __________ with the circuit when
measuring for proper voltage - -Parallel
- What is the term for a condition where a substance changes from a solid to
a gas vapor without becoming a liquid? - -Sublimation
- The MINIMUM cross-sectional dimension of a combustion air duct is
__________ inches - -3 inches
- Identify the INCORRECT method for joints in plastic fuel gas piping: - -
Threaded
- Good practice demands that when a tube constrictor is used to prep a
brazed joint, the tubes should be as close as____________ to each other. -
-.003"
- Geothermal heat pumps are considered the most efficient conditioning
systems available. These pumps can reduce energy consumption and
emissions by over__________ compared to air source heat pump's. - -40%
- Exhaust outlets shall be located NOT LESS than_________ feet horizontally
from above the air intake openings into any building. Example: a commercial
cooking exhaust outlets and air intakes. - -10 feet
- Return air openings for heating, ventilation and air-conditioning systems
shall not be taken from a closet, bathroom, toilet room, kitchen, garage,
boiler room, furnace room or unconditioned attic, however, a__________ is not
prohibited - -Bedroom
- The__________ Compressor uses a disk with radio impellers that spin rapidly
to compress refrigerant - -Centrifugal
- Enthakpy is the measure of the heat content of a substance, determined
by both the temperature in the pressure of the substance. The correct
formula for enthalpy is: - -H=M x sp.ht. x delta T
- One of the most popular types of the hermetically sealed compressors or
the reciprocating compressors, the systems typically use what type of
motor? - -Capacitor-start, induction-run
How much heat is required to melt a 10 pound block of ice that is sitting at
32 degrees F into warm water given that the heating temperature is at 80
degrees F? - -1,920 Btu/h
- In many condensing unit applications, it is necessary to heat the
compressor to evaporate liquid refrigerant trapped in the oil. Many large
compressors for commercial applications are manufactured and equipped to
handle this situation using a _________? - -Crankcase heater
- Find the MINIMUM size chimney required: A fan assisted Category 1
appliance with an input rating of 55,000 Btu/h is to be vented with a single
wall connector into a masonry chimney that is 20 feet high with a 10 foot
lateral. - -It is not recommended that this appliance be connected tot his
chimney
- Given that a motor compressor has a 2" bore and a 3" stroke, what would
be the calculated piston displacement in cubic inches? - -9.42
- A grain is a unit of weight equal to ___________, used to indicate the amount
of moisture in the air. - -1/7000 lb
- When computing heat leakage for a building, the U-value for most types of
construction can be obtained from reference books. The unit of measure for
U-value is expressed in __________? - -Btu/sq-ft/deg.F/Hr
- Absolute zero temperature is the temperature at which all molecular
motion ceases at approximately _______degrees Fahrenheit. - --460 degrees
F
- What would be the calculated resistance of a circuits load, given that the
load draws a total current of 20 amperes, and the circuit source operating
voltage is 240 VAC? - -12.0
- A contractor is working with auxiliary drain pans in a secondary drain
system for an air conditioning system. How deep should these auxiliary drain
pans be, AT LEAST? - -1-1/2 inches
- The operation of the thermostatic expansion valve is controlled by the
temperature of the thermal expansion valve and the pressure in the
evaporator. Therefore, when does the needle valve in the refrigeration
system normally open? - -When the evaporator pressure is low and the
temperature is above normal
, - According to International fire code Fire Code, duct smoke detectors in
heating and AC systems must be connected to what? - -The building fire
alarm system
- Voltmeters are always connected in __________ with the circuit when
measuring for proper voltage - -Parallel
- What is the term for a condition where a substance changes from a solid to
a gas vapor without becoming a liquid? - -Sublimation
- The MINIMUM cross-sectional dimension of a combustion air duct is
__________ inches - -3 inches
- Identify the INCORRECT method for joints in plastic fuel gas piping: - -
Threaded
- Good practice demands that when a tube constrictor is used to prep a
brazed joint, the tubes should be as close as____________ to each other. -
-.003"
- Geothermal heat pumps are considered the most efficient conditioning
systems available. These pumps can reduce energy consumption and
emissions by over__________ compared to air source heat pump's. - -40%
- Exhaust outlets shall be located NOT LESS than_________ feet horizontally
from above the air intake openings into any building. Example: a commercial
cooking exhaust outlets and air intakes. - -10 feet
- Return air openings for heating, ventilation and air-conditioning systems
shall not be taken from a closet, bathroom, toilet room, kitchen, garage,
boiler room, furnace room or unconditioned attic, however, a__________ is not
prohibited - -Bedroom
- The__________ Compressor uses a disk with radio impellers that spin rapidly
to compress refrigerant - -Centrifugal
- Enthakpy is the measure of the heat content of a substance, determined
by both the temperature in the pressure of the substance. The correct
formula for enthalpy is: - -H=M x sp.ht. x delta T
- One of the most popular types of the hermetically sealed compressors or
the reciprocating compressors, the systems typically use what type of
motor? - -Capacitor-start, induction-run
