Chapter 13 to OBT3 Final Exam with
Quality Answers 2026-2027 Updated.
The recommended hot water temperature for domestic uses
A) 160 F
B) 100 F
C) 130 F
D) 180 F - Answer C) 130 F
True or false
To repair a leakage temperature and pressure relief valve a plug would be allowed until a new
valve could be ordered - Answer False
Explain the service problems of a water tank with a broken dip tube - Answer Cold water
would not be pushed to the bottom of the tank, burner cycle would fail
"Stacking" in a water heater could be the result of - Answer short bursts of water, too much
air in the line
The term "potable water" refers to
A) water that is used in a bathroom
B) water with a high lime concentration
C) water fit for drinking and domestic use
D) Water that can be portable - Answer C) water fit for drinking and domestic use
True or false
a gravity war air system does not have a fan blower - Answer True
List 3 different types of forced air furnaces - Answer 1) Low boy
2) high boy
3) horizontal
CFM stands for - Answer "Cubic feet per minute"
if the fan motor pulley diameter is increased the fan CFM ________ (increases or decreases) -
Answer Increases
,describe the purpose of a heat exchanger - Answer to transfer heat from the burner to room
air
list some possible causes of inadequate air flow through a furnace - Answer dirty air filter,
dirty coil, locked cold air return
True or false
a cracked heat exchanger can be permanently repaired in a residence by a certified welder -
Answer False
Describe the term temperature rise - Answer change in temperature from the cold air return
to the plenum on the furnace
True or false
high efficiency furnaces are called condensing furnaces because the flue gases condense inside
the unit - Answer True
Oil fired furnaces must be certified by - Answer CSA, ULI
the proper fan tension on a blower is _____ different at the middle point of the belt - Answer
1/2
Direct drive motors can have their speeds changed by - Answer rewire motor to a different
speed terminal
what is another name for an anode rod - Answer sacrificial rod
True or false
Hard water areas can cause excessive mineral deposits in the bottom of a water heater - Answer
True
A vent connector from a forced warmed air furnace requires ______ inches clearance from
combustible material - Answer 9
Define draft - Answer current of air
One PSI is equal to _____ inches of water column pressure
, A) 1
B) 2.8
C) 28
D) 14 - Answer C) 28
All pressure measurements employed by OBT's are based on zero pressure being
A) absolute 0
B) the atmospheric pressure at sea level
C) local atmospheric pressure
D) any of the above - Answer D) any of the above
name 3 different types of draft measurement instruments - Answer incline manometer,
draftrite pressure gauge, MZF draft gauge
which statement concerning thermal draft is not correct
A) thermal draft creates a positive pressure in the vent connector
B) as the temperature of the flue gases increase, the draft is increased
C) as the outdoor temperature decreases, the draft increases
D) the higher the chimney the higher the draft - Answer A) thermal draft creates a positive
pressure in the vent connector
True or false
changing the air supply to a furnace room will have no effect on a neutral draft vented furnace -
Answer False
True or false
a dirty heat exchanger will have no effect on draft - Answer False
The law of electrical charges or the characteristics of electrical charges are - Answer opposite
charges attract each other, like charges repel one another
True or false
energy can be defined as the ability to do work - Answer True
the 3 ways that the energy of the atom can be used to transmit electricity and create other
forms of energy - Answer conduction, induction, electromagnetism
Quality Answers 2026-2027 Updated.
The recommended hot water temperature for domestic uses
A) 160 F
B) 100 F
C) 130 F
D) 180 F - Answer C) 130 F
True or false
To repair a leakage temperature and pressure relief valve a plug would be allowed until a new
valve could be ordered - Answer False
Explain the service problems of a water tank with a broken dip tube - Answer Cold water
would not be pushed to the bottom of the tank, burner cycle would fail
"Stacking" in a water heater could be the result of - Answer short bursts of water, too much
air in the line
The term "potable water" refers to
A) water that is used in a bathroom
B) water with a high lime concentration
C) water fit for drinking and domestic use
D) Water that can be portable - Answer C) water fit for drinking and domestic use
True or false
a gravity war air system does not have a fan blower - Answer True
List 3 different types of forced air furnaces - Answer 1) Low boy
2) high boy
3) horizontal
CFM stands for - Answer "Cubic feet per minute"
if the fan motor pulley diameter is increased the fan CFM ________ (increases or decreases) -
Answer Increases
,describe the purpose of a heat exchanger - Answer to transfer heat from the burner to room
air
list some possible causes of inadequate air flow through a furnace - Answer dirty air filter,
dirty coil, locked cold air return
True or false
a cracked heat exchanger can be permanently repaired in a residence by a certified welder -
Answer False
Describe the term temperature rise - Answer change in temperature from the cold air return
to the plenum on the furnace
True or false
high efficiency furnaces are called condensing furnaces because the flue gases condense inside
the unit - Answer True
Oil fired furnaces must be certified by - Answer CSA, ULI
the proper fan tension on a blower is _____ different at the middle point of the belt - Answer
1/2
Direct drive motors can have their speeds changed by - Answer rewire motor to a different
speed terminal
what is another name for an anode rod - Answer sacrificial rod
True or false
Hard water areas can cause excessive mineral deposits in the bottom of a water heater - Answer
True
A vent connector from a forced warmed air furnace requires ______ inches clearance from
combustible material - Answer 9
Define draft - Answer current of air
One PSI is equal to _____ inches of water column pressure
, A) 1
B) 2.8
C) 28
D) 14 - Answer C) 28
All pressure measurements employed by OBT's are based on zero pressure being
A) absolute 0
B) the atmospheric pressure at sea level
C) local atmospheric pressure
D) any of the above - Answer D) any of the above
name 3 different types of draft measurement instruments - Answer incline manometer,
draftrite pressure gauge, MZF draft gauge
which statement concerning thermal draft is not correct
A) thermal draft creates a positive pressure in the vent connector
B) as the temperature of the flue gases increase, the draft is increased
C) as the outdoor temperature decreases, the draft increases
D) the higher the chimney the higher the draft - Answer A) thermal draft creates a positive
pressure in the vent connector
True or false
changing the air supply to a furnace room will have no effect on a neutral draft vented furnace -
Answer False
True or false
a dirty heat exchanger will have no effect on draft - Answer False
The law of electrical charges or the characteristics of electrical charges are - Answer opposite
charges attract each other, like charges repel one another
True or false
energy can be defined as the ability to do work - Answer True
the 3 ways that the energy of the atom can be used to transmit electricity and create other
forms of energy - Answer conduction, induction, electromagnetism
