HVAC Gas Heat Exam UPDATED
ACTUAL QUESTIONS AND CORRECT
ANSWERS
To test for an obstructed flue pipe on an induced draft furnace , a technician should use ; - CORRECT
ANSWER a manometer to test the negative pressure generated by the induced draft motor
A gas furnace is to be installed in a garage . National standards require that the burners and ignition
sources must be located above the floor ; - CORRECT ANSWER 18 inches
3 . Redundant gas valves used on gas furnaces have ; - CORRECT ANSWER B. no manual gas
shut off .
Burning one cubic foot of liquified petroleum ( LP ) gas completely will produce approximately ; -
CORRECT ANSWER D. 2,000-2,500 Btu .
Liquified petroleum ( LP ) gas has a specific gravity of ; - CORRECT ANSWER C. 1.5-2.0 .
What is the purpose of using an adjustable shutter on older burners ? - CORRECT ANSWER
Mix primary air and gas
The primary function of the limit switch is to de - energize the ; - CORRECT ANSWER C. gas
valve if the furnace overheats .
A technician is using an extension ladder to work on a roof top unit . The top of the ladder should
extend beyond the support point by ; - CORRECT ANSWER C. 3 feet .
A technician determines that a natural gas furnace has a defective heat exchanger , The technician
should ; - CORRECT ANSWER Inform the homeowner and turn off the gas supply to the
furnace
The gas pressure usually required at the manifold and burners in a natural gas furnace is ; -
CORRECT ANSWER 3.5 inches WC
, The National Fuel Gas Code classifies a vent system for a condensing furnace as ; - CORRECT
ANSWER D. Category IV
The minimum distance Type - B vent pipe must be kept from combustible materials is ; - CORRECT
ANSWER D. one inch .
Typical condensing furnaces have an efficiency rating of at least ; - CORRECT ANSWER D.
90 % .
You have installed a Category IV , two - pipe vent system that terminates through the roof of the
residence . The elbow for the combustion air intake , above the roof , should ; - CORRECT ANSWER
point down .
The reason heating thermostats have anticipators or cycle rate adjustment is to - CORRECT
ANSWER reduce temperature swing .
Higher system efficiency is achieved in a category IV condensing furnace when the water vapor in the
flue gas condenses and releases ; - CORRECT ANSWER dioxide latent heat .
Natural gas consists primarily of ; - CORRECT ANSWER B. methane .
Burning one cubic foot of natural gas will produce approximately ; . - CORRECT ANSWER
900-1,100 Btu .
A furnace nameplate specifies a temperature rise of 40 to 70 degrees . Temperature measurements .
indicate a rise of 80 degrees . The most appropriate action is to ; - CORRECT ANSWER B.
increase fan speed .
A Btu is the amount of heat required to raise the temperature of one pound of water ; - CORRECT
ANSWER one - degree Fahrenheit .
Pressure drop in a natural gas piping system primarily occurs due to ; - CORRECT ANSWER
friction or resistance caused by the pipe and fittings installed in the piping system
ACTUAL QUESTIONS AND CORRECT
ANSWERS
To test for an obstructed flue pipe on an induced draft furnace , a technician should use ; - CORRECT
ANSWER a manometer to test the negative pressure generated by the induced draft motor
A gas furnace is to be installed in a garage . National standards require that the burners and ignition
sources must be located above the floor ; - CORRECT ANSWER 18 inches
3 . Redundant gas valves used on gas furnaces have ; - CORRECT ANSWER B. no manual gas
shut off .
Burning one cubic foot of liquified petroleum ( LP ) gas completely will produce approximately ; -
CORRECT ANSWER D. 2,000-2,500 Btu .
Liquified petroleum ( LP ) gas has a specific gravity of ; - CORRECT ANSWER C. 1.5-2.0 .
What is the purpose of using an adjustable shutter on older burners ? - CORRECT ANSWER
Mix primary air and gas
The primary function of the limit switch is to de - energize the ; - CORRECT ANSWER C. gas
valve if the furnace overheats .
A technician is using an extension ladder to work on a roof top unit . The top of the ladder should
extend beyond the support point by ; - CORRECT ANSWER C. 3 feet .
A technician determines that a natural gas furnace has a defective heat exchanger , The technician
should ; - CORRECT ANSWER Inform the homeowner and turn off the gas supply to the
furnace
The gas pressure usually required at the manifold and burners in a natural gas furnace is ; -
CORRECT ANSWER 3.5 inches WC
, The National Fuel Gas Code classifies a vent system for a condensing furnace as ; - CORRECT
ANSWER D. Category IV
The minimum distance Type - B vent pipe must be kept from combustible materials is ; - CORRECT
ANSWER D. one inch .
Typical condensing furnaces have an efficiency rating of at least ; - CORRECT ANSWER D.
90 % .
You have installed a Category IV , two - pipe vent system that terminates through the roof of the
residence . The elbow for the combustion air intake , above the roof , should ; - CORRECT ANSWER
point down .
The reason heating thermostats have anticipators or cycle rate adjustment is to - CORRECT
ANSWER reduce temperature swing .
Higher system efficiency is achieved in a category IV condensing furnace when the water vapor in the
flue gas condenses and releases ; - CORRECT ANSWER dioxide latent heat .
Natural gas consists primarily of ; - CORRECT ANSWER B. methane .
Burning one cubic foot of natural gas will produce approximately ; . - CORRECT ANSWER
900-1,100 Btu .
A furnace nameplate specifies a temperature rise of 40 to 70 degrees . Temperature measurements .
indicate a rise of 80 degrees . The most appropriate action is to ; - CORRECT ANSWER B.
increase fan speed .
A Btu is the amount of heat required to raise the temperature of one pound of water ; - CORRECT
ANSWER one - degree Fahrenheit .
Pressure drop in a natural gas piping system primarily occurs due to ; - CORRECT ANSWER
friction or resistance caused by the pipe and fittings installed in the piping system
