CH.109
The result of a condensate receiver, which
is too small could be:
A )
high boiler water level(s)
B ) loss of condensate to the
sewer
C )
loss of make-up water
D )
unacceptable high steam pressures
E )
low make-up water flow rates
A float operated mechanical feeder valve
should:
A )
be a normally closed valve
B )
open just after the low-water cut-off switch opens
C )
be located above the water column
D )
not be deemed a stand-by device
E ) not open until the level
is well below the feed pump cut-in level
Equalising lines on a condensate receiver
float chamber:
A ) will dampen level
fluctuations
B )
keep receiver level equal to boiler level
C )
maintain make-up flow equal to condensate flow
D )
eliminate the need for a make-up level control valve
E )
maintains equal flow of condensate to multiple boilers
Neutralising amines:
A ) raise the pH of condensate
B )
lower the pH of boiler water
C )
eliminate boiler pitting
D )
can cause return grooving
E )
absorb carbon dioxide
A condensate receiver low level cut-off
switch will:
A )
act to open a make-up solenoid
B ) stop the feedpump thereby
preventing damage to it
C )
act to close boiler fuel valve(s)
D )
sound an alarm
E )
cause the make-up valve to close
When a boiler equipped with a combination
feedwater control and low-water cut-off device shuts down due to a low-water
condition:
A )
the feedwater flow will also stop
B ) level must be restored to
above the cut-off line before the unit can be restarted
C )
it can be restarted by simply resetting the cut-off switch
D )
a manual reset switch must be used
E )
a prepurge will not be necessary
A Hartford loop will:
A )
eliminate the need for venting a steam heating system
B )
ensure continuous circulation of a hot water system
C )
prevent steam from entering a steam pressure gage
D ) prevent boiler water level
from going below the LPWL
E )
prevent the draining of an expansion tank
An electric feeder valve will:
A )
eliminate the need for a low-water fuel cut-off
B )
prevent a low-water trip
C ) open before the low-water
cut-off line is reached
D )
require manual action to open
E )
open after the unit trips on low-water
In nearly all LP steam heating systems the
feedwater:
A ) is usually condensate
B )
requires daily close scrutiny of chemical values
C )
is a high make-up percentage
D )
must be deaerated
E )
requires preheating in an economiser
A feedwater make-up system should:
A )
utilise demineralizers
B )
utilise a deaerator
C ) be able to satisfy normal
firing needs
D )
always be softened water
E )
be able to satisfy the needs of at least one boiler in a multiboiler
plant
CH.110
An ON-OFF steam boiler:
A )
will maintain a fairly constant steam pressure
B ) operates most efficiently
at continuous firing
C )
will cycle on and off based on temperature
D )
must have a low capacity
E )
cannot operate in a multiboiler system
The type of combustion fuel control
frequently used on a small package boiler, is a/an:
A )
scanner
B )
modulating control
C )
high fuel level cut-off
D )
constant pressure control
E ) on and off control
A levelling indicator is found on:
A )
the casing of a heating boiler
B )
a low-water fuel cut-off switch
C )
a boiler feedwater pump
D )
a modutrol motor
E ) an ON-OFF operating
control switch
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
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
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 ) utilising a closed liquid
filled system
D )
sensitive to steam pressure
E )
sensitive to boiler water pressure
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
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
A resistance control or
"potentiometer" for modulating control:
A ) works in conjunction with
a modutrol motor
B )
utilises 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 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
CH.111
Thermocouples are connected in series to:
A )
monitor more than one flame source
B )
increase the sensitivity of the detection system
C ) generate a higher voltage
D )
provide a spare thermocouple in case of failure of one
E )
none of the above
High limit temperature controls:
A )
increase air flow to the boiler if temperature limits are exceeded
B )
open a 3-way mixing valve to add cold water to the hot water to reduce
the water temperature
C )
are required on steam boilers
D )
are required under Section II of the ASME Codes
E ) shut off the fuel if the
water temperature is too high
A flame failure device:
A )
must be installed on every high pressure boiler
B )
will shut off the steam leaving the boiler
C )
will control the pressure of the boiler
D ) will shut off the fuel to
the burner
E )
will shut down the flame in the boiler
A flame scanner:1) requires a
photoelectric cell2) responds to temperature changes 3) requires a clear line of
sight to the flame 4) produces a steady voltage signal
A )
all of the above are correct
B )
1 & 2 are correct
C )
1, 2, & 4 are correct
D ) 1 & 3 are correct
E )
none of the above
During the start-up, a boiler equipped with
an automatic control system and flame scanning device, the main fuel supply
valve:
A ) must be opened before
ignition can take place
B )
can be opened before the flame scanner sees a flame
C )
can be opened any time during start-up sequence
D )
should be opened as soon as the pilot valve opens
E )
must be closed before ignition
Which of the following is a flame sensing
device?
A )
thermopile
B )
heat sensing control
C )
stack relay
D )
cut-off valve
E ) scanner
Fuel should be shut off immediately if it
fails to ignite:
A )
to save fuel
B ) to prevent furnace
explosions
C )
to prevent spills
D )
to save power
E )
to prevent boiler corrosion
The maximum allowable temperature for the
water in a hot water heating boiler is:
A )
100 °C
B )
150 °C
C ) 120 °C
D )
170 °C
E )
250 °C
Flame rods:
A )
should be cleaned of deposits regularly
B )
should not be exposed to temperatures above 100 degrees C
C ) should shut off the fuel
within four seconds of flame failure
D )
are very reliable and maintenance free
E )
require frequent filing of electrical contacts to prevent corrosion
build-up and failure of the device
Flame safeguard devices:
A )
are all unaffected by heat
B )
should be kept as far away from the fire as possible
C )
should not be cleaned except by a qualified serviceman
D )
should be kept cool enough to be touched by hand
E ) should be tested following
the manufacturers instructions
CH.112
Parallel blade dampers are usually used
for:
A )
changing the direction of the air flow
B )
varying the amount of air flow
C ) turning the air flow on or
off
D )
proportional operation
E )
mixed air control (outside and inside air)
A pneumatic control system:
A ) uses a sensing device to
change pressures in the control line
B )
requires an intermittent air supply
C )
always uses pressure actuated final controlled devices
D )
is not used to control air flow for ventilation
E )
is seldom used to control humidity
A pneumatic relay can also be called a:
A )
selector switch
B )
air reservoir
C )
bleed type controller
D ) cumulator
E )
pneumatic-electric switch
In a non-bleed type controller the device
that senses a change in room temperature is called a:
A )
sensing valve
B ) bellows
C )
set point gage
D )
temperature switch
E )
feedback switch
A )
reducing valve
B ) three way air valve
C )
damper
D )
pump
E )
bellows
In a self-contained control system the
energy for operation is provided by:
A )
electricity
B )
air pressure
C ) the reaction of the
sensing device
D )
a bellows
E )
a bleed type nozzle
The device used to maintain a constant
pressure throughout a pneumatic control system is called a:
A ) reducing valve
B )
control regulator
C )
pneumatic valve
D )
balancing valve
E )
none of the above
Pneumatic controllers are divided into two
basic classes:
A )
direct and indirect
B )
off/on and proportional
C )
positive and negative action
D ) bleed and non-bleed
E )
reset and gain
An example of final control device for a
heating system is a:
A )
slide-gate
B )
pump
C )
fan
D )
set of louvers
E ) all of the above
The most common type of damper operator is
a:
A )
slide
B )
ramp
C )
bellows
D ) piston
E )
pilot positioner
CH.113
An example of a controlled device would be:
A ) a damper motor operating
air louvers
B )
a hot water boiler
C )
a radiator
D )
a steam boiler
E )
a thermostat
On-off thermostats are equipped with:
A ) an open contact switch
B )
a high temperature switch
C )
a low temperature switch
D )
a high voltage switch
E )
a low voltage switch
Pressure controllers can be divided into
two classes:
A )
high and low temperature
B ) high and low pressure
C )
high and low flow
D )
inside and outside mounting
E )
all of the above
A device used to position dampers and
control valves is termed:
A )
a controller
B )
a relay
C )
a transformer
D ) an actuator
E )
a temperature controller
In a basic electric control system an
example of a controlled device is:
A )
a fuel valve
B )
a louver
C )
a diverter valve
D )
an electric switch
E ) all of the above
In a basic electrical control system the
device that senses a drop in air temperature is called the:
A )
final controlled device
B )
pneumatic temperature sensor
C )
humidistat
D ) thermostat
E )
regulator
A bimetal thermostat's operating range is
between:
A )
5 and 40 °C
B )
0 and 50 °C
C )
0 and 40 °C
D ) 10 and 32 °C
E )
50 and 90 °C
A room thermostat should be mounted on an
inside wall about:
A )
0.5 m above the floor
B )
0.75 m above the floor
C )
1.0 m above the floor
D )
1.25 m above the floor
E ) 1.5 m above the floor
Control motors are divided into two
classifications:
A )
large and small
B )
AC and DC
C ) valve operators and damper
operators
D )
high voltage and low voltage
E )
pump and fan controllers
Thermostats may be classified according to
their:
A )
application
B )
type of temperature sensing element
C )
type of control action provided
D )
temperature range
E ) all of the above
CH.114
A pressure sensor converts pressure changes
into:
A )
an electrical signal
B )
a change in electrical resistance
C ) variables such as voltage,
current, or resistance
D )
air pressure
E )
a temperature change
An example of a final control element is a:
A )
thermostat
B )
fire eye
C )
relay
D ) damper
E )
thermocouple
An electronic controller is:
A )
not part of the electronic control system
B ) used to position an
actuator
C )
used to generate a set point
D )
a type of sensor
E )
used only in pneumatic systems
An advantage of an electronic control
system is that:
A ) the controllers can accept
a wide variety of inputs
B )
they are inexpensive to operate
C )
they are inexpensive to install
D )
the controllers can be used outdoors
E )
it is very compact
Electronic controllers can be divided into
two types:
A )
on or off
B )
modulating and direct acting
C )
indirect and direct acting
D ) on or off and modulating
E )
actuators and relays
Transmitters or transducers can measure:
A )
temperature
B )
air flow
C )
air flow velocity
D )
water flow
E ) all of the above
Resistance temperature devices can provide
a relatively linear resistance variation from:
A )
-60 to 80 °C
B ) -40 to 120 °C
C )
-40 to 250 °C
D )
0 to 100 °C
E )
40 to 100 °C
An electronic control system is comprised
of a:
A )
meter, sensor, and valve
B ) sensor, controller, and
final control element
C )
sensor, transmitter, and thermostat
D )
controller, thermostat, and sensor
E )
thermostat, electronic controls, and furnace
The electrical resistance of a thermistor
will:
A )
decrease when cooled
B ) decrease when heated
C )
increase when heated
D )
remain constant with temperature changes
E )
none of the above
A transducer is a device that is used to:
A )
generate a set point
B )
produce an off or on signal
C ) convert an electronic
signal to a pneumatic output
D )
amplify an electronic signal
E )
filter an electronic signal
