MECHANICAL PRACTICE EXAM QUESTIONS AND
ANSWERS
What turns off the gas if there is a problem at a water heater and/or gas furnace? -
Answers :Thermocouple
Where is the only place cross connection is allowed/acceptable? - Answers :On the
Brine Line of a water ionization system
Appliance fuel connectors shall have a maximum overall length of - Answers :6 feet
A water temperature limiting device shall be provided to limit the hot water supplied
bathtub or whirl pool bathtub to a maximum of - Answers :120 F
The total fall in a fixture drain due to pipe slope is limited to a maximum of - Answers
:One pipe diameter
Where a fixture is separately trapped what is the maximum vertical distance permitted
fixture outlet to the trap weir? - Answers :24 inches
What chimney part prevents moisture from entering between the brick and the flue? -
Answers :Chimney cap/crown
Soot on a gas water heater door indicates: - Answers :Improper combustion (spillage)
Type B vent and hood must be a minimum of how many feet from the end of the vent? -
Answers :2 feet from the highest penetration
P-Trap cannot be greater than_____from the bottom of a lavatory basin or sink -
Answers :24''
Atmospheric vacuum breakers: - Answers :Prevent back flow
What minimum clearance from side &bottom of an openable window to forced fan vent
gas appliance? - Answers :4'-4'
What is a typical problem with a gas hot water heater supply valve? - Answers :Carbon
Build up
What is the appropriate temperature difference between return and supply A/c? -
Answers :15-20 Delta-T
Gas lines enter a room with a water heater and furnace. Where should the shut off valve
be located? - Answers :At each appliance
, Gas dryer supply line is not being used. Check: - Answers :Gas line is capped
Incomplete combustion of natural gas produces: - Answers :Carbon Monoxide; Life
expectancy is 6 years
Using a mirror and flashlight to view the heat exchanger on a gas furnace allows you to
see - Answers :Les than 20% of the heat exchanger
The vent connector should slope: - Answers :Upward going away from the furnace at
minimum quarter inch per foot
How much should a belt deflect when it is under proper tension? - Answers :About an
inch
What is required to be checked on air conditioning system? - Answers :Temperature
Differential
What does the yellow tipped flame on a gas furnace indicate? - Answers :Insufficient
Primary Air
When the heat pump capacity exactly matches heating loss during heat pump operation
occurs? - Answers :Balance Point which is 70F
What color should the flame on a gas furnace be? - Answers :Blue
What shuts off the burners on a gas furnace when the output temperature is excessive?
- Answers :Limit Switch
A sound in the tub after flushing the toilet might be caused by - Answers :Toilet not
resealing after flushing
Whites the most common cause of a leaking faucet? - Answers :worn out washer
What is a crown/trap weir? - Answers :An interior projection in the outlet side of the
trap/to aid in maintaining the seal
What are the components to a restroom toilet? - Answers :Flapper seal, ballcock, bowl,
tank, valve,handle, fill tube
What locations can an electric water heater be located? - Answers :Per manufacturers
installation instruction
Dryer flex duct line should be? - Answers :6 ft not concealed/ 8 ft not concealed
Footer or floor drains should be installed where? - Answers :Laundry room/wet bar area
with ice maker
ANSWERS
What turns off the gas if there is a problem at a water heater and/or gas furnace? -
Answers :Thermocouple
Where is the only place cross connection is allowed/acceptable? - Answers :On the
Brine Line of a water ionization system
Appliance fuel connectors shall have a maximum overall length of - Answers :6 feet
A water temperature limiting device shall be provided to limit the hot water supplied
bathtub or whirl pool bathtub to a maximum of - Answers :120 F
The total fall in a fixture drain due to pipe slope is limited to a maximum of - Answers
:One pipe diameter
Where a fixture is separately trapped what is the maximum vertical distance permitted
fixture outlet to the trap weir? - Answers :24 inches
What chimney part prevents moisture from entering between the brick and the flue? -
Answers :Chimney cap/crown
Soot on a gas water heater door indicates: - Answers :Improper combustion (spillage)
Type B vent and hood must be a minimum of how many feet from the end of the vent? -
Answers :2 feet from the highest penetration
P-Trap cannot be greater than_____from the bottom of a lavatory basin or sink -
Answers :24''
Atmospheric vacuum breakers: - Answers :Prevent back flow
What minimum clearance from side &bottom of an openable window to forced fan vent
gas appliance? - Answers :4'-4'
What is a typical problem with a gas hot water heater supply valve? - Answers :Carbon
Build up
What is the appropriate temperature difference between return and supply A/c? -
Answers :15-20 Delta-T
Gas lines enter a room with a water heater and furnace. Where should the shut off valve
be located? - Answers :At each appliance
, Gas dryer supply line is not being used. Check: - Answers :Gas line is capped
Incomplete combustion of natural gas produces: - Answers :Carbon Monoxide; Life
expectancy is 6 years
Using a mirror and flashlight to view the heat exchanger on a gas furnace allows you to
see - Answers :Les than 20% of the heat exchanger
The vent connector should slope: - Answers :Upward going away from the furnace at
minimum quarter inch per foot
How much should a belt deflect when it is under proper tension? - Answers :About an
inch
What is required to be checked on air conditioning system? - Answers :Temperature
Differential
What does the yellow tipped flame on a gas furnace indicate? - Answers :Insufficient
Primary Air
When the heat pump capacity exactly matches heating loss during heat pump operation
occurs? - Answers :Balance Point which is 70F
What color should the flame on a gas furnace be? - Answers :Blue
What shuts off the burners on a gas furnace when the output temperature is excessive?
- Answers :Limit Switch
A sound in the tub after flushing the toilet might be caused by - Answers :Toilet not
resealing after flushing
Whites the most common cause of a leaking faucet? - Answers :worn out washer
What is a crown/trap weir? - Answers :An interior projection in the outlet side of the
trap/to aid in maintaining the seal
What are the components to a restroom toilet? - Answers :Flapper seal, ballcock, bowl,
tank, valve,handle, fill tube
What locations can an electric water heater be located? - Answers :Per manufacturers
installation instruction
Dryer flex duct line should be? - Answers :6 ft not concealed/ 8 ft not concealed
Footer or floor drains should be installed where? - Answers :Laundry room/wet bar area
with ice maker
