HVAC Exams Questions Correctly Answered and
Updated 2025!!!
In a fin-coil heat exchanger, the primary source of heat for the heat exchanger is
_____________.
a) steam or hot water
b) hot glycol
c) hot oil
d) hot circulating air - ANSWER a) steam or hot water
High efficiency furnaces and heaters range in annual fuel utilization efficiency (AFUE)
from __________.
a) 94-98%
b) 80-96%
c) 70-75%
d) 60-70% - ANSWER b) 80-96%
Which of the following is not a type of heat source or heat exchanger used in forced
warm air heating systems?
a) directly fired
b) electrical resistance coil
c) glycol heater
d) fin coil heat exchanger - ANSWER c) glycol heater
,Which of the following is not an advantage of a forced air heating system?
a) air may be cleaned by filters
b) air can be humidified by using a humidifier
c) positive air circulation promotes a more uniform temperature distribution
d) blower noise can be carried through the ducts - ANSWER d) blower noise can be
carried through the ducts
The heating coils in an electric resistance warm air furnace are usually powered by
_____ volts.
a) 120
b) 150
c) 325
d) 240 - ANSWER d) 240
In a pulse burner, the pulse combustion process occurs about __ to __ times per second.
a) 30, 40
b) 60, 70
c) 25, 30
d) 40, 50 - ANSWER b) 60, 70
Main parts of a warm air heating system? - ANSWER -central furnace or heat exchanger
-ducting
-outlets
,-return grilles
Where are warm air heating systems most extensively used?
Why? - ANSWER -residences and other small buildings
-cost of installation and maintenance less then water or steam systems
---can be easily modified for full air conditioning
What is the purpose of a secondary warm air heating system in a large building?
What is usually the primary source of heating in a large building? - ANSWER -supply the
remainder of heat not supplied by the primary system
---also provide fresh, filtered, heated, humidified outside air for ventilation and
humidification
-primary source is usually a hot water or steam heating system
3 classes of heating sources used in warm air heating systems? - ANSWER -directly fired
-electrical resistance coil
-fin-coil heat exchanger
Directly fired? - ANSWER -self enclosed unit
-circulates air through heat exchanger by a blower
-air does not contact the products of combustion directly
, Why is the use of electric resistance coils generally limited to residences? - ANSWER -the
high cost of electricity
How are directly fired forced warm air furnaces classified? - ANSWER -direction of air
flow
-height
-fuel used
-heating capacities
Where would a low boy furnace be used?
Air enters? Leaves?
Height? - ANSWER -limited head room
-return duct at the top through a filter/ supply duct also at the top
-approx 1.2m (4ft)
Where would a horizontal furnace be used?
Height? - ANSWER -limited head room (ie attics and crawl spaces)
---can be suspended from ceiling
-approx 0.6m
Updated 2025!!!
In a fin-coil heat exchanger, the primary source of heat for the heat exchanger is
_____________.
a) steam or hot water
b) hot glycol
c) hot oil
d) hot circulating air - ANSWER a) steam or hot water
High efficiency furnaces and heaters range in annual fuel utilization efficiency (AFUE)
from __________.
a) 94-98%
b) 80-96%
c) 70-75%
d) 60-70% - ANSWER b) 80-96%
Which of the following is not a type of heat source or heat exchanger used in forced
warm air heating systems?
a) directly fired
b) electrical resistance coil
c) glycol heater
d) fin coil heat exchanger - ANSWER c) glycol heater
,Which of the following is not an advantage of a forced air heating system?
a) air may be cleaned by filters
b) air can be humidified by using a humidifier
c) positive air circulation promotes a more uniform temperature distribution
d) blower noise can be carried through the ducts - ANSWER d) blower noise can be
carried through the ducts
The heating coils in an electric resistance warm air furnace are usually powered by
_____ volts.
a) 120
b) 150
c) 325
d) 240 - ANSWER d) 240
In a pulse burner, the pulse combustion process occurs about __ to __ times per second.
a) 30, 40
b) 60, 70
c) 25, 30
d) 40, 50 - ANSWER b) 60, 70
Main parts of a warm air heating system? - ANSWER -central furnace or heat exchanger
-ducting
-outlets
,-return grilles
Where are warm air heating systems most extensively used?
Why? - ANSWER -residences and other small buildings
-cost of installation and maintenance less then water or steam systems
---can be easily modified for full air conditioning
What is the purpose of a secondary warm air heating system in a large building?
What is usually the primary source of heating in a large building? - ANSWER -supply the
remainder of heat not supplied by the primary system
---also provide fresh, filtered, heated, humidified outside air for ventilation and
humidification
-primary source is usually a hot water or steam heating system
3 classes of heating sources used in warm air heating systems? - ANSWER -directly fired
-electrical resistance coil
-fin-coil heat exchanger
Directly fired? - ANSWER -self enclosed unit
-circulates air through heat exchanger by a blower
-air does not contact the products of combustion directly
, Why is the use of electric resistance coils generally limited to residences? - ANSWER -the
high cost of electricity
How are directly fired forced warm air furnaces classified? - ANSWER -direction of air
flow
-height
-fuel used
-heating capacities
Where would a low boy furnace be used?
Air enters? Leaves?
Height? - ANSWER -limited head room
-return duct at the top through a filter/ supply duct also at the top
-approx 1.2m (4ft)
Where would a horizontal furnace be used?
Height? - ANSWER -limited head room (ie attics and crawl spaces)
---can be suspended from ceiling
-approx 0.6m
