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21 Cards in this Set
- Front
- Back
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An ON-OFF steam boiler |
b) operates most efficiently at continuous firing
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A modulating control steam heating boiler
a) is always fully automatic b) will have a wide operating pressure range c) has very efficient operation d) will have a constant combustion air flow rate e) cannot operate in a multiboiler system |
c) has very efficient operation
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An operating control switch for an ON-OFF boiler
a) uses a differential spring to reduce cycling b) can only have its cut-in setting adjusted c) has an unadjustable span between cut-in and cut-out d) utilizes a resistance coil e) operates in conjunction with a modutrol motor |
a) uses a differential spring to reduce cycling
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A levelling indicator is found on
a) the casing of a heating boiler b) a low-water fuel cutoff switch c) a boiler feedwater pump d) a modutrol motor e) an ON-OFF operating control switch |
e) an ON-OFF operating control switch
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An item found upstream of an operating control switch is a
a) modutrol motor b) siphon c) combustion air proving switch d) test connection for an inspector e) feedwater pressure gage |
b) siphon
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On a multiburner boiler the high fire nozzle will
a) be in operation on start-up b) operate continuously when steam demand exceeds boiler capacity c) be ignited by a pilot flame d) respond to electrical resistance e) operate regardless of where the manual over-ride switch is set |
b) operate continuously when steam demand exceeds boiler
capacity |
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A manual "high-low" switch should be switched to "high" or
"auto" a) as soon as the main flame has stabilized b) prior to ignition of the main flame c) when pressure is too low d) when the boiler has been properly warmed up e) during boiler pre-purge |
d) when the boiler has been properly warmed up
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resistance control or "potentiometer" for modulating
control a) works in conjunction with a modutrol motor b) utilizes a mercury switch c) senses steam temperature d) can only be used on a fully automatic boiler e) can operate only in the vertical position |
a) works in conjunction with a modutrol motor
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A potentiometer control
a) varies electrical current to a modutrol motor b) will start and stop a boiler c) cannot have its settings adjusted d) eliminates the need for a high limit control e) will not result in simultaneous adjustment of air and fuel |
a) varies electrical current to a modutrol motor
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A high limit control switch
a) is necessary on all boilers b) activates after the safety valve opens c) is a normally open switch d) usually does not require manual resetting e) must be used when a boiler is not under continuous supervision |
e) must be used when a boiler is not under continuous
supervision |
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Prior to a boiler safety valve popping during routine boiler
operation a) a try lever test should be performed b) the pressure gage should be checked c) the high limit switch should open d) the feedwater pump should stop e) the high level alarm should sound |
c) the high limit switch should open
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A hot water boiler operating control can be a pressure switch
a) which is normally open b) which is sensitive to the expansion and contraction of boiler water c) utilizing a closed liquid filled system d) sensitive to steam pressure e) sensitive to boiler water pressure |
b) which is sensitive to the expansion and contraction of
boiler water |
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A thermal element is
a) used to measure pressure b) capable of sensing temperature and converting it to a pressure signal c) a type of open system d) used to measure heat content e) commonly termed an "aquastat" |
b) capable of sensing temperature and converting it to a
pressure signal |
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An aquastat
a) senses water level b) is like a thermal element without a capillary tube c) can be located away from its point of measurement d) measures water flow e) is a modulating device |
b) is like a thermal element without a capillary tube
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A low fire switch
a) is a type of manual over-ride b) takes no part in the start-up of an automatic boiler c) is a normally closed switch d) utilizes a thermal element for its operation e) acts as an interlock to ensure minimum damper setting |
e) acts as an interlock to ensure minimum damper setting
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What is the purpose of the high limit temperature control on
a hot water boiler? a) to take over operating the boiler if the water level control fails b) to allow you to take off the operating control for maintenance without shutting down the boiler c) to shut down the burner if the water temperature rises too high d) to prevent the pressure in the boiler rising above 210 kPa gage e) to limit high pressure and temperature from developing in the boiler |
c) to shut down the burner if the water temperature rises
too high |
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Combustion air safety switches are commonly found
a) on natural draft boilers b) on hot water boilers only c) on boilers utilizing a forced draft fan d) on gas fired boilers only e) as noninterlocking devices and take no part in a startup |
c) on boilers utilizing a forced draft fan
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A high gas pressure fuel cut-off switch
a) closes when gas pressure is too high b) is never a manual reset device c) must be located upstream of an automatic fuel valve d) is a normally open switch e) opens when gas pressure is too high |
e) opens when gas pressure is too high
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A test lead or "jumper wire" is required when testing
a) high steam pressure or water temperature limiting controls b) a high gas pressure fuel cut-off switch c) a safety valve with the test lever d) the low water fuel cut-off switch e) a low gas pressure fuel cut-off |
a) high steam pressure or water temperature limiting
controls |
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Quickly closing the main burner manual cock valve during
boiler operation should check the a) flame scanner b) combustion air proving switch c) low gas pressure fuel cut-off d) high gas pressure fuel cut-off e) low fire interlock switch |
d) high gas pressure fuel cut-off
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The combustion air proving switch
a) should be checked when air flow is minimum b) should not be checked while the boiler is in the purge cycle of start-up c) is a normally closed switch d) must always be a manual reset device e) should be checked when air flow is maximum |
e) should be checked when air flow is maximum |
