1
Grade 3 Engineering Omaha Exam Prep
by NAPE Updated Version 2025-2026.
Quizs & Correct Answers. Graded A
# 112 Why is a boiler feed pump used on some boilers and not others? -
ANS you will not need a pump if the operating pressure of the boiler is
below city water pressure
# 89 If maintenance was done on your boiler, put back in operation, and the
stack temperature was higher than normal, what would you look for as the
cause? - ANSwater tube boiler: most likely defective or missing baffles
fire tube boiler: could be missing turbulators or blocked tubes
#1 How can you loose your license? - ANSdrinking on the job, sleeping on
the job, negligence unsafe work, signing a falsified license application for
someone, failing to renew your license annually
#10 What is a crown sheet and its purpose?
-----
what is a tube sheet and its purpose? - ANSin a vertical firetube boiler
holds the tubes and is thicker because it is exposed to the fire.
-----
holds the tubes and does not see the fire
1
, 2
#100 How high above the top row of tubes in an HRT boiler must the lower
gauge cock be set to have a safe amount of water at this point? - ANSat
least 3" above the top row of tubes
#101 Name 3 appliances that can warn you of low water - ANS1) water
sight glass
2) low water alarm
3) fusible plug
#102 If your boiler has only one low water cutoff, what is the ASME code
requirement? - ANSit must be a manual reset.
Side note: the City of Omaha requires one to be a manual reset even if you
have 2 cutoffs. if there is repair work done on the boiler there must be a
manual reset added.
#103 What is the purpose of a high fire limit control on a boiler?
-----
what is a modulating control? - ANSit proves that the forced fan damper
has fully opened prior to starting the pre-purge period to insure adequate
purge air flow.
-----
it adjusts the firing rate of the burner to maintain the boiler steam pressure
#104 Is an automatic shutoff allowed between the boiler and the water
column? - ANSNO, only between the water column and gauge glass
2
, 3
#105 What type valves are allowed between the boiler and the water
column? - ANSonly O.S.&Y. valves or stopcocks which are locked or
sealed open. (outside screw & yolk)
#106 Name 2 types of fusible plugs - ANS1) fire side
2) water side
refers to the side where they are installed
#107 What is a bourdon tube? - ANSA curved tube with an oval cross-
section. One end is attached to the frame and pressure connection. The
other end is attached to a pointer by linkage and gears. An increase in
pressure tends to straighten the tube; its motion is transmitted to the
pointer.
#108 What is a siphon tube and what is it used for? - ANSa siphon tube or
pigtail loop protects the mechanism of a gauge from live steam.
#109 What pressure range should the steam gauge be when used on a
boiler? - ANSit should be a compound gauge at least 1 1/2 times the
maximum allowable working pressure
#11 What is a water leg on a boiler? - ANSspace between the outer shell
and the furnace containing boiler water. it absorbs heat that would be
wasted and increases the capacity of the boiler. the surfaces are flat and
must be stayed.
#110 Where is the steam gauge connected to the boiler?
3
, 4
-----
how do you properly mount a steam gauge to a boiler? - ANSmounted on
top of the water column or the the top of the steam drum.
-----
gauge is mounted with:
1) a siphon tube
2) a isolation valve
3) a test connection
#111 Name 3 types of feed-water regulator systems - ANS1) On-off such
as float or probe
2) Modulating such as thermodynamic or thermohydrolic
3) Metering such as a two or three ement
#113 What is the most important valve on a boiler? - ANSSAFETY VALVE!
#114 What is a safety valve?
-----
how does it operate? - ANSa device to EXPEL ALL EXCESS steam
pressure from a boiler
-----
the huddling chamber causes the valve to open fully and quickly causing a
definite drop in pressure before closing
#115 A safety valve is limited to how many square feet of heating surface? -
ANSany boiler with more than 500 square feet of heating surface must
have 2 or more safety valves
4
Grade 3 Engineering Omaha Exam Prep
by NAPE Updated Version 2025-2026.
Quizs & Correct Answers. Graded A
# 112 Why is a boiler feed pump used on some boilers and not others? -
ANS you will not need a pump if the operating pressure of the boiler is
below city water pressure
# 89 If maintenance was done on your boiler, put back in operation, and the
stack temperature was higher than normal, what would you look for as the
cause? - ANSwater tube boiler: most likely defective or missing baffles
fire tube boiler: could be missing turbulators or blocked tubes
#1 How can you loose your license? - ANSdrinking on the job, sleeping on
the job, negligence unsafe work, signing a falsified license application for
someone, failing to renew your license annually
#10 What is a crown sheet and its purpose?
-----
what is a tube sheet and its purpose? - ANSin a vertical firetube boiler
holds the tubes and is thicker because it is exposed to the fire.
-----
holds the tubes and does not see the fire
1
, 2
#100 How high above the top row of tubes in an HRT boiler must the lower
gauge cock be set to have a safe amount of water at this point? - ANSat
least 3" above the top row of tubes
#101 Name 3 appliances that can warn you of low water - ANS1) water
sight glass
2) low water alarm
3) fusible plug
#102 If your boiler has only one low water cutoff, what is the ASME code
requirement? - ANSit must be a manual reset.
Side note: the City of Omaha requires one to be a manual reset even if you
have 2 cutoffs. if there is repair work done on the boiler there must be a
manual reset added.
#103 What is the purpose of a high fire limit control on a boiler?
-----
what is a modulating control? - ANSit proves that the forced fan damper
has fully opened prior to starting the pre-purge period to insure adequate
purge air flow.
-----
it adjusts the firing rate of the burner to maintain the boiler steam pressure
#104 Is an automatic shutoff allowed between the boiler and the water
column? - ANSNO, only between the water column and gauge glass
2
, 3
#105 What type valves are allowed between the boiler and the water
column? - ANSonly O.S.&Y. valves or stopcocks which are locked or
sealed open. (outside screw & yolk)
#106 Name 2 types of fusible plugs - ANS1) fire side
2) water side
refers to the side where they are installed
#107 What is a bourdon tube? - ANSA curved tube with an oval cross-
section. One end is attached to the frame and pressure connection. The
other end is attached to a pointer by linkage and gears. An increase in
pressure tends to straighten the tube; its motion is transmitted to the
pointer.
#108 What is a siphon tube and what is it used for? - ANSa siphon tube or
pigtail loop protects the mechanism of a gauge from live steam.
#109 What pressure range should the steam gauge be when used on a
boiler? - ANSit should be a compound gauge at least 1 1/2 times the
maximum allowable working pressure
#11 What is a water leg on a boiler? - ANSspace between the outer shell
and the furnace containing boiler water. it absorbs heat that would be
wasted and increases the capacity of the boiler. the surfaces are flat and
must be stayed.
#110 Where is the steam gauge connected to the boiler?
3
, 4
-----
how do you properly mount a steam gauge to a boiler? - ANSmounted on
top of the water column or the the top of the steam drum.
-----
gauge is mounted with:
1) a siphon tube
2) a isolation valve
3) a test connection
#111 Name 3 types of feed-water regulator systems - ANS1) On-off such
as float or probe
2) Modulating such as thermodynamic or thermohydrolic
3) Metering such as a two or three ement
#113 What is the most important valve on a boiler? - ANSSAFETY VALVE!
#114 What is a safety valve?
-----
how does it operate? - ANSa device to EXPEL ALL EXCESS steam
pressure from a boiler
-----
the huddling chamber causes the valve to open fully and quickly causing a
definite drop in pressure before closing
#115 A safety valve is limited to how many square feet of heating surface? -
ANSany boiler with more than 500 square feet of heating surface must
have 2 or more safety valves
4
