Power engineering 5th class final
exam
A boiler item which should be checked monthly is: - ANS - The flame detection system
A complete check of the boiler heating system should be carried out: - ANS - At the
end of the heating season
A disadvantage of condensing boilers is that: - ANS - The boilers are more expensive
than customary boilers
A fin coil consists of one or more rows of parallel tubes fitted with fins to
_____________exchange. - ANS - Increase the rate of heat
A heating boiler must have a permanently attached marker indicating: - ANS - Lowest
permissible water level
A leaking steam trap will allow steam to blow from the radiator into the: - ANS - Return
lines
A low percentage (15%) of the energy delivered by the electricity is absorbed as heat in
the boiler.
true or false - ANS - False
A machined and slightly tapered piece of pipe found in cast-iron sectional heating
boilers is referred to as a: - ANS - Push nipple
A modular cast-iron heating boiler - ANS - Consists of a number of horizontal
sectional cast-iron boilers
A pipe siphon is used on a boiler to: - ANS - Maintain a water seal between the steam
and the Bourdon tube
A pressure gauge can most accurately be calibrated by using: - ANS - A dead weight
tester
,A programming control on a natural draft gas fired boiler operates in the following
sequence. - ANS - The operating control initiates a startup
The load relay energizes the ignition transformer and the pilot gas valve
The flame detector senses the flame and causes the main gas valve to open
The main burner is ignited
The ignition transformer and pilot gas valve are de-energized and closed, if an
interrupted pilot is used
A thermocouple consists of two dissimilar wires welded together at one end to form a: -
ANS - Hot junction
A valve commonly used as a boiler stop valve is the _____ valve. - ANS - Gate
Air is basically composed of a mixture of oxygen and nitrogen. The approximate
proportions are _____ oxygen and _____nitrogen by volume. - ANS - 21%, 79%
Air is composed of mostly: - ANS - Nitrogen
All valves must be properly identified with one of the markings indicating the: - ANS -
Manufacturer's name or trademark
Allowance for expansion and contraction of piping is necessary because of the
___________ changes the piping material is subjected to. - ANS - Temperature
An advantage of a multiple heating boiler plant is: - ANS - Most low capacity can be
moved through standard sized doorways
An advantage of a refractory burner is: - ANS - The short luminous flame spreads
over a large cross-section of the furnace resulting in high radiant heat transfer
An advantage of an electric boiler is the: - ANS - Compactness of the boiler
An advantage of plastic piping is: - ANS - Ease of assembly
An automatic/manual selector switch is provided on a boiler with the following burner
control system. - ANS - Modulating fire control
An immersion type electric boiler has - ANS - elements
, An intermittent pilot: - ANS - Is automatically ignited at the start of each burner
operation and continues to burn throughout the main burner period
As per applicable code the pressure and temperature limiting factors for steam and hot
water heating boilers are: - ANS - 103 kPa (15 psi) for steam and 121˚C or 1100 kPa
(250˚F or 160 psi) for hot water
At normal boiler steaming rates, a condensate receiver tank should contain a sufficient
volume of water equivalent to the water evaporated by the boiler for a maximum period
of _____ minutes. - ANS - 30
Attached to the tube of the convector are metal fins that serve to ___________ transfer
from the tube to the air circulating passed the convector. - ANS - Increase the heat
Before a boiler can be fired it must first have a/an: - ANS - Current inspection
certificate
Before assembly the threads must be thoroughly cleaned and a small amount of thick
lubricant, sometimes called pipe dope, is applied to the: - ANS - Male pipe threads
Black light is the popular name for invisible light in the near _________ range of wave
lengths. - ANS - Ultraviolet
Black steel piping cannot be used for ___________ lines. - ANS - Potable (drinking
water) water
Boiler explosions may be listed under two general classifications: - ANS - Furnace
explosions and Pressure explosions
Boiler fittings are: - ANS - Devices directly attached to the pressure part of a boiler
Boiler gauge glass packing nuts may be tightened: - ANS - Once the pressure has
been removed
Boiler stack temperature is rising due to soot build-up on the boiler tubes. This could: -
ANS - Cause a furnace explosion
Building air infiltration should be kept to a minimum even if a certain amount of fresh air
is required to provide ___________ within the building. - ANS - Ventilation
exam
A boiler item which should be checked monthly is: - ANS - The flame detection system
A complete check of the boiler heating system should be carried out: - ANS - At the
end of the heating season
A disadvantage of condensing boilers is that: - ANS - The boilers are more expensive
than customary boilers
A fin coil consists of one or more rows of parallel tubes fitted with fins to
_____________exchange. - ANS - Increase the rate of heat
A heating boiler must have a permanently attached marker indicating: - ANS - Lowest
permissible water level
A leaking steam trap will allow steam to blow from the radiator into the: - ANS - Return
lines
A low percentage (15%) of the energy delivered by the electricity is absorbed as heat in
the boiler.
true or false - ANS - False
A machined and slightly tapered piece of pipe found in cast-iron sectional heating
boilers is referred to as a: - ANS - Push nipple
A modular cast-iron heating boiler - ANS - Consists of a number of horizontal
sectional cast-iron boilers
A pipe siphon is used on a boiler to: - ANS - Maintain a water seal between the steam
and the Bourdon tube
A pressure gauge can most accurately be calibrated by using: - ANS - A dead weight
tester
,A programming control on a natural draft gas fired boiler operates in the following
sequence. - ANS - The operating control initiates a startup
The load relay energizes the ignition transformer and the pilot gas valve
The flame detector senses the flame and causes the main gas valve to open
The main burner is ignited
The ignition transformer and pilot gas valve are de-energized and closed, if an
interrupted pilot is used
A thermocouple consists of two dissimilar wires welded together at one end to form a: -
ANS - Hot junction
A valve commonly used as a boiler stop valve is the _____ valve. - ANS - Gate
Air is basically composed of a mixture of oxygen and nitrogen. The approximate
proportions are _____ oxygen and _____nitrogen by volume. - ANS - 21%, 79%
Air is composed of mostly: - ANS - Nitrogen
All valves must be properly identified with one of the markings indicating the: - ANS -
Manufacturer's name or trademark
Allowance for expansion and contraction of piping is necessary because of the
___________ changes the piping material is subjected to. - ANS - Temperature
An advantage of a multiple heating boiler plant is: - ANS - Most low capacity can be
moved through standard sized doorways
An advantage of a refractory burner is: - ANS - The short luminous flame spreads
over a large cross-section of the furnace resulting in high radiant heat transfer
An advantage of an electric boiler is the: - ANS - Compactness of the boiler
An advantage of plastic piping is: - ANS - Ease of assembly
An automatic/manual selector switch is provided on a boiler with the following burner
control system. - ANS - Modulating fire control
An immersion type electric boiler has - ANS - elements
, An intermittent pilot: - ANS - Is automatically ignited at the start of each burner
operation and continues to burn throughout the main burner period
As per applicable code the pressure and temperature limiting factors for steam and hot
water heating boilers are: - ANS - 103 kPa (15 psi) for steam and 121˚C or 1100 kPa
(250˚F or 160 psi) for hot water
At normal boiler steaming rates, a condensate receiver tank should contain a sufficient
volume of water equivalent to the water evaporated by the boiler for a maximum period
of _____ minutes. - ANS - 30
Attached to the tube of the convector are metal fins that serve to ___________ transfer
from the tube to the air circulating passed the convector. - ANS - Increase the heat
Before a boiler can be fired it must first have a/an: - ANS - Current inspection
certificate
Before assembly the threads must be thoroughly cleaned and a small amount of thick
lubricant, sometimes called pipe dope, is applied to the: - ANS - Male pipe threads
Black light is the popular name for invisible light in the near _________ range of wave
lengths. - ANS - Ultraviolet
Black steel piping cannot be used for ___________ lines. - ANS - Potable (drinking
water) water
Boiler explosions may be listed under two general classifications: - ANS - Furnace
explosions and Pressure explosions
Boiler fittings are: - ANS - Devices directly attached to the pressure part of a boiler
Boiler gauge glass packing nuts may be tightened: - ANS - Once the pressure has
been removed
Boiler stack temperature is rising due to soot build-up on the boiler tubes. This could: -
ANS - Cause a furnace explosion
Building air infiltration should be kept to a minimum even if a certain amount of fresh air
is required to provide ___________ within the building. - ANS - Ventilation
