age 1 of 37
HVAC UNIT 31 GAS HEAT REVIEW QUESTIONS WITH
ANSWERS
How can you measure the flame current? ......ANSWER........Place
the microammeter in series withwww the wire coming from the
burner ground terminal to the module.
How do auxiliary limit switches work? ......ANSWER........They are
used for counterflow and horizontal furnaces. They are usually
bimetallic and are mounted on the warm air blower housing to
they can monitor room return air temperature and interrupt the
burners when the temperature gets too hot.
Name the four main components of a gas fired heating system.
......ANSWER........Manifold and controls
Burners
,age 2 of 37
Heat exchanger
Venting system
Name the four types of furnace flow patterns.
......ANSWER........Upflow
Low-boy
Downflow
Horizontal
Which type of furnace is usually found in basements that have
low headroom? ......ANSWER........Low-boy
What is another name for a downflow furnace?
......ANSWER........Counterflow
,age 3 of 37
Where do you usually find horizontal furnaces?
......ANSWER........In crawl spaces, attics and suspended from
floor joists in basements.
What is so special about multipoise furnaces?
......ANSWER........They can be installed in any position. They are
very versatile and give installers the option of upflow,
downflow, horizontal right or horizontal left discharge.
Why do multipoise furnaces have extra safety controls?
......ANSWER........Because these furnaces can be placed in four
different configurations, they must multiple safety controls
designed into the furnace.
Where are flame rollout switches usually installed?
......ANSWER........They are installed near the top of the burner
box, where the flame is most likely to roll out.
, age 4 of 37
Are vent limit / draft safeguard switches NC or NO and what
do they do? ......ANSWER........They are NC switches and monitor
the draft hood temperature and open when there is any spillage
of flue ga0
What are the three commonly used gas fuels?
......ANSWER........Natural gas
Manufactured gas
Liquified petroleum or LP gas
What is the specific gravity of natural gas and is it lighter than
air? ......ANSWER........The specific gravity is .60 and it ish lighter
than air so it rises.
HVAC UNIT 31 GAS HEAT REVIEW QUESTIONS WITH
ANSWERS
How can you measure the flame current? ......ANSWER........Place
the microammeter in series withwww the wire coming from the
burner ground terminal to the module.
How do auxiliary limit switches work? ......ANSWER........They are
used for counterflow and horizontal furnaces. They are usually
bimetallic and are mounted on the warm air blower housing to
they can monitor room return air temperature and interrupt the
burners when the temperature gets too hot.
Name the four main components of a gas fired heating system.
......ANSWER........Manifold and controls
Burners
,age 2 of 37
Heat exchanger
Venting system
Name the four types of furnace flow patterns.
......ANSWER........Upflow
Low-boy
Downflow
Horizontal
Which type of furnace is usually found in basements that have
low headroom? ......ANSWER........Low-boy
What is another name for a downflow furnace?
......ANSWER........Counterflow
,age 3 of 37
Where do you usually find horizontal furnaces?
......ANSWER........In crawl spaces, attics and suspended from
floor joists in basements.
What is so special about multipoise furnaces?
......ANSWER........They can be installed in any position. They are
very versatile and give installers the option of upflow,
downflow, horizontal right or horizontal left discharge.
Why do multipoise furnaces have extra safety controls?
......ANSWER........Because these furnaces can be placed in four
different configurations, they must multiple safety controls
designed into the furnace.
Where are flame rollout switches usually installed?
......ANSWER........They are installed near the top of the burner
box, where the flame is most likely to roll out.
, age 4 of 37
Are vent limit / draft safeguard switches NC or NO and what
do they do? ......ANSWER........They are NC switches and monitor
the draft hood temperature and open when there is any spillage
of flue ga0
What are the three commonly used gas fuels?
......ANSWER........Natural gas
Manufactured gas
Liquified petroleum or LP gas
What is the specific gravity of natural gas and is it lighter than
air? ......ANSWER........The specific gravity is .60 and it ish lighter
than air so it rises.
