4B - Unit 3 - Boiler Safety Devices Latest Update
2025-2026 Actual Exam 90 Questions with 100%
Verified Correct Answers Guaranteed A+ Verified
by Professor
A blowdown ring is used on a safety valve to:
Select one:
a. Adjust the differential between opening and closing pressures
b. Increase the blowdown frequency of the safety valve
c. Prevent the safety valve from popping while blowing down the boiler
d. Adjust the operating pressure of the valve - CORRECT ANSWER: a
A boiler feedwater isolation valve:
Select one:
a. May be a globe valve, provided water enters below the disc
b. Should be located close to the feedwater pump
c. Must be a globe valve
d. Is used to isolate the deaerator - CORRECT ANSWER: a
A boiler with a single safety valve has a maximum allowable working pressure of 1000
kPa. What is the maximum boiler pressure permissible when the safety valve is
blowing?
Select one:
a. 1100 kPa
b. 1030 kPa
c. 1000 kPa
d. 1060 kPa - CORRECT ANSWER: d
,A feedwater pipe, where connected to a power boiler, must have:
Select one:
a. A quick and slow opening stop valve
b. A stop valve only
c. A check valve between the stop valve and the boiler
d. A check valve, with a stop valve between the check valve and the boiler - CORRECT
ANSWER: d
A flame failure device is unresponsive to:
Select one:
a. Fuel flow
b. Visible light
c. Infra-red light
d. Ultraviolet light - CORRECT ANSWER: a
A flame rod:
Select one:
a. Develops a high resistance in the presence of a flame.
b. Forms an electric circuit with the rod, flame and burner
c. Is used only for oil fired burners
d. Is used in combination with a photocell - CORRECT ANSWER: b
A float operated low water fuel cutoff has its switch separated from boiler pressure by:
Select one:
a. Packing
b. A seal cage
, c. A bellows
d. A float cage - CORRECT ANSWER: c
A gauge glass shows the level of a clear, colourless liquid as very dark, is the
______________ gauge glass.
Select one:
a. Flat
b. Tubular
c. Reflex
d. Bi-colour - CORRECT ANSWER: c
A high gas pressure fuel cut-off switch:
Select one:
a. Prevents excessive fuel pressure from creating an unstable flame condition
b. Is located upstream of the automatic fuel valve
c. Automatically resets itself when the gas pressure is restored
d. Closes when gas pressure is too high - CORRECT ANSWER: a
A high pressure boiler with a heating surface not exceeding _________ in area can
have only a single safety valve.
Select one:
a. 19 m2
b. 28 m2
c. 36 m2
d. 47 m2 - CORRECT ANSWER: d
A hot water boiler operating control (Aquastat) may be a pressure switch:
Select one:
2025-2026 Actual Exam 90 Questions with 100%
Verified Correct Answers Guaranteed A+ Verified
by Professor
A blowdown ring is used on a safety valve to:
Select one:
a. Adjust the differential between opening and closing pressures
b. Increase the blowdown frequency of the safety valve
c. Prevent the safety valve from popping while blowing down the boiler
d. Adjust the operating pressure of the valve - CORRECT ANSWER: a
A boiler feedwater isolation valve:
Select one:
a. May be a globe valve, provided water enters below the disc
b. Should be located close to the feedwater pump
c. Must be a globe valve
d. Is used to isolate the deaerator - CORRECT ANSWER: a
A boiler with a single safety valve has a maximum allowable working pressure of 1000
kPa. What is the maximum boiler pressure permissible when the safety valve is
blowing?
Select one:
a. 1100 kPa
b. 1030 kPa
c. 1000 kPa
d. 1060 kPa - CORRECT ANSWER: d
,A feedwater pipe, where connected to a power boiler, must have:
Select one:
a. A quick and slow opening stop valve
b. A stop valve only
c. A check valve between the stop valve and the boiler
d. A check valve, with a stop valve between the check valve and the boiler - CORRECT
ANSWER: d
A flame failure device is unresponsive to:
Select one:
a. Fuel flow
b. Visible light
c. Infra-red light
d. Ultraviolet light - CORRECT ANSWER: a
A flame rod:
Select one:
a. Develops a high resistance in the presence of a flame.
b. Forms an electric circuit with the rod, flame and burner
c. Is used only for oil fired burners
d. Is used in combination with a photocell - CORRECT ANSWER: b
A float operated low water fuel cutoff has its switch separated from boiler pressure by:
Select one:
a. Packing
b. A seal cage
, c. A bellows
d. A float cage - CORRECT ANSWER: c
A gauge glass shows the level of a clear, colourless liquid as very dark, is the
______________ gauge glass.
Select one:
a. Flat
b. Tubular
c. Reflex
d. Bi-colour - CORRECT ANSWER: c
A high gas pressure fuel cut-off switch:
Select one:
a. Prevents excessive fuel pressure from creating an unstable flame condition
b. Is located upstream of the automatic fuel valve
c. Automatically resets itself when the gas pressure is restored
d. Closes when gas pressure is too high - CORRECT ANSWER: a
A high pressure boiler with a heating surface not exceeding _________ in area can
have only a single safety valve.
Select one:
a. 19 m2
b. 28 m2
c. 36 m2
d. 47 m2 - CORRECT ANSWER: d
A hot water boiler operating control (Aquastat) may be a pressure switch:
Select one:
