Gas Technician 3 TSSA Practice Exam
UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
Main component of natural gas - CORRECT ANSWER Methane
Primary function of a thermocouple in a gas appliance - CORRECT ANSWER To
detect the presence of a pilot flame and shut off gas if the flame goes out
What to do if you smell gas in a building - CORRECT ANSWER Shut off the gas
supply, evacuate the building, and call the gas company
Typical pressure of natural gas supplied to residential homes - CORRECT ANSWER 7
inches water column (0.25 psi)
Type of piping commonly used for underground gas installations - CORRECT
ANSWER Polyethylene (PE)
Purpose of a gas regulator - CORRECT ANSWER To reduce and control gas pressure
Minimum clearance required between a gas meter and a window - CORRECT
ANSWER 36 inches
Primary safety hazard of incomplete combustion in a gas appliance - CORRECT
ANSWER Carbon monoxide production
Typical color of a properly adjusted natural gas flame - CORRECT ANSWER Blue
Safety device that shuts off the gas supply if the pilot light goes out - CORRECT
ANSWER Thermocouple
,Primary purpose of venting in a gas appliance - CORRECT ANSWER To expel
combustion gases
What to do if a gas appliance fails a pressure test - CORRECT ANSWER Repair the
leaks and retest
Purpose of a drip leg (sediment trap) in a gas piping system - CORRECT ANSWER To
collect debris and moisture before it enters the appliance
Role of a gas pressure relief valve - CORRECT ANSWER To release excess gas
pressure
Primary function of a flame rollout switch in a gas appliance - CORRECT
ANSWER To shut off the gas if flames roll out of the combustion chamber
Gas added to natural gas for leak detection - CORRECT ANSWER Mercaptan
Component responsible for circulating air in a gas furnace - CORRECT
ANSWER Blower motor
Type of ignition system commonly found in modern gas appliances - CORRECT
ANSWER Hot surface ignition
What to do if a gas appliance produces a yellow flame instead of blue - CORRECT
ANSWER Check for insufficient air supply
Proper ratio of gas to air for complete combustion of natural gas - CORRECT
ANSWER 10:1
, Safety device that shuts off the gas supply in the event of high temperature in a gas furnace -
CORRECT ANSWER Limit switch
Purpose of a pressure regulator vent - CORRECT ANSWER To vent excess gas if the
regulator fails
Purpose of a high-limit switch in a gas furnace - CORRECT ANSWER To shut off the
burner if the furnace overheats
Type B vent - CORRECT ANSWER A vent designed for gas appliances that operate
with a positive pressure.
Single-wall vent - CORRECT ANSWER A type of vent that consists of a single layer
of material.
Direct vent (two-pipe system) - CORRECT ANSWER A venting system that uses two
pipes: one for intake and one for exhaust.
Chimney vent - CORRECT ANSWER A traditional venting system that uses a
chimney to exhaust gases.
Typical ignition temperature for natural gas - CORRECT ANSWER 1,100°F.
Action if a gas appliance fails to ignite - CORRECT ANSWER Shut off the gas supply
and investigate the issue.
Primary byproduct of complete combustion of natural gas - CORRECT
ANSWER Water vapor and carbon dioxide.
Purpose of a flame sensor in a gas furnace - CORRECT ANSWER To detect the
presence of a flame and shut off gas if no flame is detected.
UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
Main component of natural gas - CORRECT ANSWER Methane
Primary function of a thermocouple in a gas appliance - CORRECT ANSWER To
detect the presence of a pilot flame and shut off gas if the flame goes out
What to do if you smell gas in a building - CORRECT ANSWER Shut off the gas
supply, evacuate the building, and call the gas company
Typical pressure of natural gas supplied to residential homes - CORRECT ANSWER 7
inches water column (0.25 psi)
Type of piping commonly used for underground gas installations - CORRECT
ANSWER Polyethylene (PE)
Purpose of a gas regulator - CORRECT ANSWER To reduce and control gas pressure
Minimum clearance required between a gas meter and a window - CORRECT
ANSWER 36 inches
Primary safety hazard of incomplete combustion in a gas appliance - CORRECT
ANSWER Carbon monoxide production
Typical color of a properly adjusted natural gas flame - CORRECT ANSWER Blue
Safety device that shuts off the gas supply if the pilot light goes out - CORRECT
ANSWER Thermocouple
,Primary purpose of venting in a gas appliance - CORRECT ANSWER To expel
combustion gases
What to do if a gas appliance fails a pressure test - CORRECT ANSWER Repair the
leaks and retest
Purpose of a drip leg (sediment trap) in a gas piping system - CORRECT ANSWER To
collect debris and moisture before it enters the appliance
Role of a gas pressure relief valve - CORRECT ANSWER To release excess gas
pressure
Primary function of a flame rollout switch in a gas appliance - CORRECT
ANSWER To shut off the gas if flames roll out of the combustion chamber
Gas added to natural gas for leak detection - CORRECT ANSWER Mercaptan
Component responsible for circulating air in a gas furnace - CORRECT
ANSWER Blower motor
Type of ignition system commonly found in modern gas appliances - CORRECT
ANSWER Hot surface ignition
What to do if a gas appliance produces a yellow flame instead of blue - CORRECT
ANSWER Check for insufficient air supply
Proper ratio of gas to air for complete combustion of natural gas - CORRECT
ANSWER 10:1
, Safety device that shuts off the gas supply in the event of high temperature in a gas furnace -
CORRECT ANSWER Limit switch
Purpose of a pressure regulator vent - CORRECT ANSWER To vent excess gas if the
regulator fails
Purpose of a high-limit switch in a gas furnace - CORRECT ANSWER To shut off the
burner if the furnace overheats
Type B vent - CORRECT ANSWER A vent designed for gas appliances that operate
with a positive pressure.
Single-wall vent - CORRECT ANSWER A type of vent that consists of a single layer
of material.
Direct vent (two-pipe system) - CORRECT ANSWER A venting system that uses two
pipes: one for intake and one for exhaust.
Chimney vent - CORRECT ANSWER A traditional venting system that uses a
chimney to exhaust gases.
Typical ignition temperature for natural gas - CORRECT ANSWER 1,100°F.
Action if a gas appliance fails to ignite - CORRECT ANSWER Shut off the gas supply
and investigate the issue.
Primary byproduct of complete combustion of natural gas - CORRECT
ANSWER Water vapor and carbon dioxide.
Purpose of a flame sensor in a gas furnace - CORRECT ANSWER To detect the
presence of a flame and shut off gas if no flame is detected.
