G2 Prep Test [ACTUAL EXAM] LATEST VERSION [QUESTIONS AND
ANSWERS] WITH PRACTICE EXAM DETAILED AND VERIFIED FOR
GUARANTEED PASS- LATEST UPDATE 2025 GRADED A
When sizing a branch line, what is the minimum size of job fabricated welded
fitting that can be used on a NPS 6" gas supply header - CORRECT ANSWER
2" NPS
The instrument used to determine the polarity of an appliance power supply is the
- CORRECT ANSWER Voltmeter
Direct current travels - CORRECT ANSWER In one direction
A 120V power supply for a residential electrical circuit is taken from the -
CORRECT ANSWER Load side of one branch circuit breaker and neutral lug
A hard sharp pilot flame indicates - CORRECT ANSWER The orifice is too
small
Which tool is used to determine if the windings on an electric motor have shorted
- CORRECT ANSWER Voltmeter
When the voltage has been determined to be approximately 120V, which scale on
an analog meter should be selected for the most accuracy - CORRECT
ANSWER 0-125V
One millivolt is equal to - CORRECT ANSWER 1/1000 volt
When checking a circuit of an unknown voltage using an analog meter with 0-30V,
0-125V, 0-250V and 0-600V which scale should be selected - CORRECT
ANSWER 0-600 V
The 24 V control circuit supply for a residential gas furnace comes from a -
CORRECT ANSWER 120/24 step down transformer
As gauge number of a conductor increases, it's current carrying capacity -
CORRECT ANSWER Decreases
The instrument used to determine potential difference in an electrical circuit is
the - CORRECT ANSWER Voltmeter
,The open circuit test reading of a thermocouple should be in the range of -
CORRECT ANSWER 25-30 mV
As the diameter of a wire increase, it's resistance - CORRECT ANSWER
decreases
Millivolt wiring should be isolated from line voltage wiring because - CORRECT
ANSWER The line voltage will induce a voltage into the millivolt wiring
A schematic diagram is used to - CORRECT ANSWER Indicate how the
system works
A thermopile or power pile generates - CORRECT ANSWER Hundreds of
Millivolts (up to 750 mV)
An operating aqua stat is what type of control - CORRECT ANSWER
Normally closed
The resistance of a heating thermistor does what as its temperature rises -
CORRECT ANSWER Decreases
An intermittent pilot is present - CORRECT ANSWER From the time there is a
call for heat until the call has ended
A probe type low water cut-off switch is what type of control - CORRECT
ANSWER Normally open
How much of the appliance-rated gas is supplied to a burner using a two stage
gas valve the thermostat calls for the second stage of heat - CORRECT
ANSWER 100%
A diode - CORRECT ANSWER Allows current flow in one direction only
A thermostat serving a unit which has seperate heating and cooling control
transformer and has one stage of heating and one stage of cooling is a -
CORRECT ANSWER Single pole double throw
What safety control protects a steam boiler if the condensate pump fails to return
condensate to the boiler - CORRECT ANSWER Low water cut off
Trial for Ignition is the time allowed - CORRECT ANSWER Establish ignition
,it is permissible to use gas piping as an electrical ground if - CORRECT
ANSWER it is used as a flame safeguard circuit
A temperature control with a narrow differential will cause a very - CORRECT
ANSWER Close temperature control and short on cycles
If the heat anticipator of a thermostat is set too low, what probable condition
would exist when the heating unit is operating - CORRECT ANSWER Short
cycling of the main burner
A thermostat with a single mercury bulb which controls a single stage heat,
single stage cooling is a _____________ controls - CORRECT ANSWER
Single pole double throw
In a normal thermocouple application, the expected drop out reading is from -
CORRECT ANSWER 2-4 mV
The best method of removing dust from a house is by - CORRECT ANSWER
Filtration
After a direct vent radiant heating system in installed in a new house the cutomer
complains that "The walls and windows are wet". From the following list what is
the most reasonable response - CORRECT ANSWER Recommend the
installation of a mechanical ventilation system
When air is heated, its relative humidity - CORRECT ANSWER remains
constant
Determine the minimum required size of the combustion air opening from
outdoors given the following:
There are 2 appliances in a 10x10x20 structure which has a continuously sealed
vapour barrier and has an equivalent leakage area of 0.05m squared at a
differential pressure of 10 Pasacals (Pa). One appliance has a draft hood and an
input of 75,000 Btu/h. The second appliance has an input of 100,000 BTu/h and
does not have a draft hood. The required combustion air opening size is -
CORRECT ANSWER 25 square inches
The best way to seal against air leaks is to - CORRECT ANSWER Caulk
When an air supply duct is used to provide the outside air supply, it shall
terminate within __________ feet above, and within _________ feet horizontally
from the burner level of the applinace having the largest input - CORRECT
ANSWER 1'-2'
, A depressurization test conected on a house will help determine the - CORRECT
ANSWER Potential for pressure-induced back-drafting in the house
The instrument used to preform a passive depressurization test is a - CORRECT
ANSWER Magnahelic gauge
Vapour barriers should be installed on - CORRECT ANSWER The warm side
of the insulation
The best way to remove odours from a house is to - CORRECT ANSWER
Ventilate the house
Air enters the house through a process called - CORRECT ANSWER
Infiltration
A boiler room contains the following natural draft appliances
- 2 hot water boilers, each firing at 750,000 Btu/h
- 1 water heater firing at 270,000 Btu/h
- 1 water heater firing at 30,000 Btu/h
What is the minimum required ventilation air opening - CORRECT ANSWER
20 square inches
Which is the most common cause of the flue gas spillage form the gas appliances
- CORRECT ANSWER Negative air pressure caused by mechanical system
A poorly insulated building could result in - CORRECT ANSWER Increased
fuel consumption
What is the minimum size of a combustion air opening from outdoors for an
appliance with a draft hood and having an input of 120,000 Btu/h installed in a
structure that has a continuous vapor barrier and has an equivalent leakage area
of 0.05m sq. at a differential pressure of 10 Pascals (Pa) and dimensions of
10x10x20 - CORRECT ANSWER 10 square inches
When a baffle is required to prevent the direct entry of rain into an air supply
opening, by how much can the baffle reduce the required free area of the opening
- CORRECT ANSWER 0%
Conduction is - CORRECT ANSWER The transfer of heat from particle to
particle
ANSWERS] WITH PRACTICE EXAM DETAILED AND VERIFIED FOR
GUARANTEED PASS- LATEST UPDATE 2025 GRADED A
When sizing a branch line, what is the minimum size of job fabricated welded
fitting that can be used on a NPS 6" gas supply header - CORRECT ANSWER
2" NPS
The instrument used to determine the polarity of an appliance power supply is the
- CORRECT ANSWER Voltmeter
Direct current travels - CORRECT ANSWER In one direction
A 120V power supply for a residential electrical circuit is taken from the -
CORRECT ANSWER Load side of one branch circuit breaker and neutral lug
A hard sharp pilot flame indicates - CORRECT ANSWER The orifice is too
small
Which tool is used to determine if the windings on an electric motor have shorted
- CORRECT ANSWER Voltmeter
When the voltage has been determined to be approximately 120V, which scale on
an analog meter should be selected for the most accuracy - CORRECT
ANSWER 0-125V
One millivolt is equal to - CORRECT ANSWER 1/1000 volt
When checking a circuit of an unknown voltage using an analog meter with 0-30V,
0-125V, 0-250V and 0-600V which scale should be selected - CORRECT
ANSWER 0-600 V
The 24 V control circuit supply for a residential gas furnace comes from a -
CORRECT ANSWER 120/24 step down transformer
As gauge number of a conductor increases, it's current carrying capacity -
CORRECT ANSWER Decreases
The instrument used to determine potential difference in an electrical circuit is
the - CORRECT ANSWER Voltmeter
,The open circuit test reading of a thermocouple should be in the range of -
CORRECT ANSWER 25-30 mV
As the diameter of a wire increase, it's resistance - CORRECT ANSWER
decreases
Millivolt wiring should be isolated from line voltage wiring because - CORRECT
ANSWER The line voltage will induce a voltage into the millivolt wiring
A schematic diagram is used to - CORRECT ANSWER Indicate how the
system works
A thermopile or power pile generates - CORRECT ANSWER Hundreds of
Millivolts (up to 750 mV)
An operating aqua stat is what type of control - CORRECT ANSWER
Normally closed
The resistance of a heating thermistor does what as its temperature rises -
CORRECT ANSWER Decreases
An intermittent pilot is present - CORRECT ANSWER From the time there is a
call for heat until the call has ended
A probe type low water cut-off switch is what type of control - CORRECT
ANSWER Normally open
How much of the appliance-rated gas is supplied to a burner using a two stage
gas valve the thermostat calls for the second stage of heat - CORRECT
ANSWER 100%
A diode - CORRECT ANSWER Allows current flow in one direction only
A thermostat serving a unit which has seperate heating and cooling control
transformer and has one stage of heating and one stage of cooling is a -
CORRECT ANSWER Single pole double throw
What safety control protects a steam boiler if the condensate pump fails to return
condensate to the boiler - CORRECT ANSWER Low water cut off
Trial for Ignition is the time allowed - CORRECT ANSWER Establish ignition
,it is permissible to use gas piping as an electrical ground if - CORRECT
ANSWER it is used as a flame safeguard circuit
A temperature control with a narrow differential will cause a very - CORRECT
ANSWER Close temperature control and short on cycles
If the heat anticipator of a thermostat is set too low, what probable condition
would exist when the heating unit is operating - CORRECT ANSWER Short
cycling of the main burner
A thermostat with a single mercury bulb which controls a single stage heat,
single stage cooling is a _____________ controls - CORRECT ANSWER
Single pole double throw
In a normal thermocouple application, the expected drop out reading is from -
CORRECT ANSWER 2-4 mV
The best method of removing dust from a house is by - CORRECT ANSWER
Filtration
After a direct vent radiant heating system in installed in a new house the cutomer
complains that "The walls and windows are wet". From the following list what is
the most reasonable response - CORRECT ANSWER Recommend the
installation of a mechanical ventilation system
When air is heated, its relative humidity - CORRECT ANSWER remains
constant
Determine the minimum required size of the combustion air opening from
outdoors given the following:
There are 2 appliances in a 10x10x20 structure which has a continuously sealed
vapour barrier and has an equivalent leakage area of 0.05m squared at a
differential pressure of 10 Pasacals (Pa). One appliance has a draft hood and an
input of 75,000 Btu/h. The second appliance has an input of 100,000 BTu/h and
does not have a draft hood. The required combustion air opening size is -
CORRECT ANSWER 25 square inches
The best way to seal against air leaks is to - CORRECT ANSWER Caulk
When an air supply duct is used to provide the outside air supply, it shall
terminate within __________ feet above, and within _________ feet horizontally
from the burner level of the applinace having the largest input - CORRECT
ANSWER 1'-2'
, A depressurization test conected on a house will help determine the - CORRECT
ANSWER Potential for pressure-induced back-drafting in the house
The instrument used to preform a passive depressurization test is a - CORRECT
ANSWER Magnahelic gauge
Vapour barriers should be installed on - CORRECT ANSWER The warm side
of the insulation
The best way to remove odours from a house is to - CORRECT ANSWER
Ventilate the house
Air enters the house through a process called - CORRECT ANSWER
Infiltration
A boiler room contains the following natural draft appliances
- 2 hot water boilers, each firing at 750,000 Btu/h
- 1 water heater firing at 270,000 Btu/h
- 1 water heater firing at 30,000 Btu/h
What is the minimum required ventilation air opening - CORRECT ANSWER
20 square inches
Which is the most common cause of the flue gas spillage form the gas appliances
- CORRECT ANSWER Negative air pressure caused by mechanical system
A poorly insulated building could result in - CORRECT ANSWER Increased
fuel consumption
What is the minimum size of a combustion air opening from outdoors for an
appliance with a draft hood and having an input of 120,000 Btu/h installed in a
structure that has a continuous vapor barrier and has an equivalent leakage area
of 0.05m sq. at a differential pressure of 10 Pascals (Pa) and dimensions of
10x10x20 - CORRECT ANSWER 10 square inches
When a baffle is required to prevent the direct entry of rain into an air supply
opening, by how much can the baffle reduce the required free area of the opening
- CORRECT ANSWER 0%
Conduction is - CORRECT ANSWER The transfer of heat from particle to
particle
