G2 Gas Technician Module 18 UPDATED
ACTUAL Exam Questions and CORRECT
Answers
What is a temperature control made of in a water heater? Which one is the sensing element? -
CORRECT ANSWER - Rod and tube. Rod is steel and tube is copper. Copper is the
sensing element.
Temperature settings on a water heater? - CORRECT ANSWER - Hot - 160 F
Normal - 130 F
Warm - 120 F
What does a unitrol have in it? - CORRECT ANSWER - Temperature and pressure relief
valve, E.C.O., Main Gas valves, Pilot Gas Valve and a gas regulator
What temp does a temperature and pressure relief valve fusible link melt at? Pressure relieve at?
- CORRECT ANSWER - Melts at 210 F and relieves itself at 150 psi
How does a dip tube function? - CORRECT ANSWER - Allows cold water to enter near
the bottom of the tank as hot water exits the top
What do anodes do in a water heater? When do you need to change them? - CORRECT
ANSWER - Prevents the interior of the tank from corroding and should be changed when
its diameter is 3/8"
What are the components of an instantaneous water heater? - CORRECT ANSWER -
Pump, pump control, flow switch, temperature and pressure relief valve, and a limit control
What must be done with a Twinned Water heater system to ensure it runs properly? - CORRECT
ANSWER - Inlet and outlet piping must have equal resistance on each tank.
, What clearance must a direct vent water heater have on the burner side? - CORRECT
ANSWER - 3 feet
What metals are not acceptable in potable water applications? - CORRECT ANSWER -
Ferrous metals
What is the maximum allowable length of supply and return piping in a combination water
heating system? - CORRECT ANSWER - Max supply and return piping is 50 feet
Can you use chemicals in a combination system? - CORRECT ANSWER - No
How do you size the pumps in a combination system? - CORRECT ANSWER - To match
the flow requirements of the heating system
What is the minimum size and type of water heater that is recommended for a combination
system? - CORRECT ANSWER - 40 gallon high-recovery or high efficiency gas-fired
water heater
What temperature difference do you want from inlet to outlet on a combination system? -
CORRECT ANSWER - 20 F
How do you size a circulating pump? - CORRECT ANSWER - 1 gpm for each 10000 btuh
and friction loss is 1 foot for each 40 feet of pipe
What controls the water temp and gas pressure on a direct fired storage heater? - CORRECT
ANSWER - Unitrol
What are the components of a direct fired storage heater(under fired storage heater) - CORRECT
ANSWER - Dip tube, anode, temperature and pressure relief valve, and mixing valve
ACTUAL Exam Questions and CORRECT
Answers
What is a temperature control made of in a water heater? Which one is the sensing element? -
CORRECT ANSWER - Rod and tube. Rod is steel and tube is copper. Copper is the
sensing element.
Temperature settings on a water heater? - CORRECT ANSWER - Hot - 160 F
Normal - 130 F
Warm - 120 F
What does a unitrol have in it? - CORRECT ANSWER - Temperature and pressure relief
valve, E.C.O., Main Gas valves, Pilot Gas Valve and a gas regulator
What temp does a temperature and pressure relief valve fusible link melt at? Pressure relieve at?
- CORRECT ANSWER - Melts at 210 F and relieves itself at 150 psi
How does a dip tube function? - CORRECT ANSWER - Allows cold water to enter near
the bottom of the tank as hot water exits the top
What do anodes do in a water heater? When do you need to change them? - CORRECT
ANSWER - Prevents the interior of the tank from corroding and should be changed when
its diameter is 3/8"
What are the components of an instantaneous water heater? - CORRECT ANSWER -
Pump, pump control, flow switch, temperature and pressure relief valve, and a limit control
What must be done with a Twinned Water heater system to ensure it runs properly? - CORRECT
ANSWER - Inlet and outlet piping must have equal resistance on each tank.
, What clearance must a direct vent water heater have on the burner side? - CORRECT
ANSWER - 3 feet
What metals are not acceptable in potable water applications? - CORRECT ANSWER -
Ferrous metals
What is the maximum allowable length of supply and return piping in a combination water
heating system? - CORRECT ANSWER - Max supply and return piping is 50 feet
Can you use chemicals in a combination system? - CORRECT ANSWER - No
How do you size the pumps in a combination system? - CORRECT ANSWER - To match
the flow requirements of the heating system
What is the minimum size and type of water heater that is recommended for a combination
system? - CORRECT ANSWER - 40 gallon high-recovery or high efficiency gas-fired
water heater
What temperature difference do you want from inlet to outlet on a combination system? -
CORRECT ANSWER - 20 F
How do you size a circulating pump? - CORRECT ANSWER - 1 gpm for each 10000 btuh
and friction loss is 1 foot for each 40 feet of pipe
What controls the water temp and gas pressure on a direct fired storage heater? - CORRECT
ANSWER - Unitrol
What are the components of a direct fired storage heater(under fired storage heater) - CORRECT
ANSWER - Dip tube, anode, temperature and pressure relief valve, and mixing valve
