NATE Gas Furnace Service Preparation Version 3
Newest 2026-2027 With Complete Questions And
Correct Detailed Answers| Brand New Version!
Floor diffusers should be installed in boots or register boxes using -
ANSWER-Sheet metal screws and banding
When suspended with metal strap and no saddle, flexible duct should
be supported with a minimum strap with of - ANSWER-1 ½"
Spray-type atomizing humidifiers are installed to discharge moisture
into - ANSWER-The supply duct
A technician is installing a gas furnace and the customer has decided
not to install an air conditioner. How will their decision affect the
installation of the supply ductwork - ANSWER-Adequate space should
be allowed for addition of a coil in the future
Electronic air cleaners (EAC) installed in a gas furnace system should be
wired so they only operate - ANSWER-When the EAC ON-OFF switch is
turned to ON and the supply air blower is operating
1|Page
,Why is the polarity of a 120V gas furnace equipped with electronic
flame rectification important - ANSWER-The ignition control may not
prove the flame
Before starting a gas furnace after its installation, the technician should
do a visual check of all wiring on the equipment. Which of the following
must be included with these checks - ANSWER-A check that all
connections are secure and tight
Using a voltmeter, how does a technician determine voltage drop at a
gas furnace - ANSWER-With the furnace not operating and the with the
furnace operating
How is the setting on a 4 speed PSC blower motor changed - ANSWER-
Changing the motor tap connections
An important consideration when installing a motorized economizer is
to check to be certain that - ANSWER-The vanes operate without
binding
When starting up a dual fuel system, the temperature rise method for
determining air flow cannot be used with the compressor cycle of the
heat pump because - ANSWER-The capacity of the system varies too
much with the outdoor temperature
2|Page
,What flame pattern would the technician expect to see on a properly
operating single stage furnace equipped with in-shot type burners -
ANSWER-A hard forceful flame with a light blue appearance and little or
no yellow
Which of the following is recommended for a pressurization leak test of
a fuel gas pipe - ANSWER-Compressed air
Which of the following is used to measure air pressure - ANSWER-
Diaphragm type differential pressure gauge
A technician wishes to determine the airflow of a gas furnace on startup
using temperature rise method. The gas meter has been clocked and
gas flow rate has been determined. The gas heating value is known. The
heat rise across the heat exchanger is measures. What should the
technician do next to find the CFM - ANSWER-Calculate the CFM using a
formula
A dirty or clogged filter in an operating gas furnace can cause -
ANSWER-An increase in temperature rise
3|Page
, Why are leak detecting solutions specifically formulated for use on gas
piping preferred over household soap solutions - ANSWER-Leak
detection solutions will not damage the piping
Bent vanes of a direct blower wheel in a gas furnace can cause -
ANSWER-Loss in airflow, excessive blower motor wear and increased
noise
A gas clothes dryer can interfere with the operation of a nearby natural
draft gas furnace with an atmospheric burner by - ANSWER-Stealing the
combustion air preventing complete fuel burning
During a preventative maintenance check of a gas furnace, ductwork
should always be checked for - ANSWER-Leaks and damages
Which of the following is likely a problem if a gas furnace has a
temperature differential across the heat exchanger which exceeds the
value on the manufacturer's data plate - ANSWER-Inadequate system
airflow
When performing preventing maintenance on a gas furnace, check the
wiring to be certain - ANSWER-No wire are broken or loosened
4|Page
Newest 2026-2027 With Complete Questions And
Correct Detailed Answers| Brand New Version!
Floor diffusers should be installed in boots or register boxes using -
ANSWER-Sheet metal screws and banding
When suspended with metal strap and no saddle, flexible duct should
be supported with a minimum strap with of - ANSWER-1 ½"
Spray-type atomizing humidifiers are installed to discharge moisture
into - ANSWER-The supply duct
A technician is installing a gas furnace and the customer has decided
not to install an air conditioner. How will their decision affect the
installation of the supply ductwork - ANSWER-Adequate space should
be allowed for addition of a coil in the future
Electronic air cleaners (EAC) installed in a gas furnace system should be
wired so they only operate - ANSWER-When the EAC ON-OFF switch is
turned to ON and the supply air blower is operating
1|Page
,Why is the polarity of a 120V gas furnace equipped with electronic
flame rectification important - ANSWER-The ignition control may not
prove the flame
Before starting a gas furnace after its installation, the technician should
do a visual check of all wiring on the equipment. Which of the following
must be included with these checks - ANSWER-A check that all
connections are secure and tight
Using a voltmeter, how does a technician determine voltage drop at a
gas furnace - ANSWER-With the furnace not operating and the with the
furnace operating
How is the setting on a 4 speed PSC blower motor changed - ANSWER-
Changing the motor tap connections
An important consideration when installing a motorized economizer is
to check to be certain that - ANSWER-The vanes operate without
binding
When starting up a dual fuel system, the temperature rise method for
determining air flow cannot be used with the compressor cycle of the
heat pump because - ANSWER-The capacity of the system varies too
much with the outdoor temperature
2|Page
,What flame pattern would the technician expect to see on a properly
operating single stage furnace equipped with in-shot type burners -
ANSWER-A hard forceful flame with a light blue appearance and little or
no yellow
Which of the following is recommended for a pressurization leak test of
a fuel gas pipe - ANSWER-Compressed air
Which of the following is used to measure air pressure - ANSWER-
Diaphragm type differential pressure gauge
A technician wishes to determine the airflow of a gas furnace on startup
using temperature rise method. The gas meter has been clocked and
gas flow rate has been determined. The gas heating value is known. The
heat rise across the heat exchanger is measures. What should the
technician do next to find the CFM - ANSWER-Calculate the CFM using a
formula
A dirty or clogged filter in an operating gas furnace can cause -
ANSWER-An increase in temperature rise
3|Page
, Why are leak detecting solutions specifically formulated for use on gas
piping preferred over household soap solutions - ANSWER-Leak
detection solutions will not damage the piping
Bent vanes of a direct blower wheel in a gas furnace can cause -
ANSWER-Loss in airflow, excessive blower motor wear and increased
noise
A gas clothes dryer can interfere with the operation of a nearby natural
draft gas furnace with an atmospheric burner by - ANSWER-Stealing the
combustion air preventing complete fuel burning
During a preventative maintenance check of a gas furnace, ductwork
should always be checked for - ANSWER-Leaks and damages
Which of the following is likely a problem if a gas furnace has a
temperature differential across the heat exchanger which exceeds the
value on the manufacturer's data plate - ANSWER-Inadequate system
airflow
When performing preventing maintenance on a gas furnace, check the
wiring to be certain - ANSWER-No wire are broken or loosened
4|Page
