HVAC contractor exam test 7 with questions and
correct answers
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? - CORRECT ANSWERS-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 _________? - CORRECT ANSWERS-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. - CORRECT ANSWERS-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? - CORRECT ANSWERS-9.42
A grain is a unit of weight equal to ___________, used to indicate the amount of moisture in the air. -
CORRECT ANSWERS-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 __________? - CORRECT
ANSWERS-Btu/sq-ft/deg.F/Hr
Absolute zero temperature is the temperature at which all molecular motion ceases at approximately
_______degrees Fahrenheit. - CORRECT ANSWERS--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? - CORRECT ANSWERS-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? - CORRECT ANSWERS-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? - CORRECT ANSWERS-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? - CORRECT ANSWERS-The building fire alarm system
Voltmeters are always connected in __________ with the circuit when measuring for proper voltage -
CORRECT ANSWERS-Parallel
What is the term for a condition where a substance changes from a solid to a gas vapor without
becoming a liquid? - CORRECT ANSWERS-Sublimation
The MINIMUM cross-sectional dimension of a combustion air duct is __________ inches - CORRECT
ANSWERS-3 inches
Identify the INCORRECT method for joints in plastic fuel gas piping: - CORRECT ANSWERS-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. - CORRECT ANSWERS-.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.
- CORRECT ANSWERS-40%
correct answers
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? - CORRECT ANSWERS-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 _________? - CORRECT ANSWERS-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. - CORRECT ANSWERS-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? - CORRECT ANSWERS-9.42
A grain is a unit of weight equal to ___________, used to indicate the amount of moisture in the air. -
CORRECT ANSWERS-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 __________? - CORRECT
ANSWERS-Btu/sq-ft/deg.F/Hr
Absolute zero temperature is the temperature at which all molecular motion ceases at approximately
_______degrees Fahrenheit. - CORRECT ANSWERS--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? - CORRECT ANSWERS-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? - CORRECT ANSWERS-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? - CORRECT ANSWERS-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? - CORRECT ANSWERS-The building fire alarm system
Voltmeters are always connected in __________ with the circuit when measuring for proper voltage -
CORRECT ANSWERS-Parallel
What is the term for a condition where a substance changes from a solid to a gas vapor without
becoming a liquid? - CORRECT ANSWERS-Sublimation
The MINIMUM cross-sectional dimension of a combustion air duct is __________ inches - CORRECT
ANSWERS-3 inches
Identify the INCORRECT method for joints in plastic fuel gas piping: - CORRECT ANSWERS-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. - CORRECT ANSWERS-.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.
- CORRECT ANSWERS-40%
