4B Older Practice questions Controls Flashcards
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 multi-boiler system
b. Operates most efficiently at continuous firing
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 multi-boiler system
c. Has very efficient operation
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
e. On and off control
A high limit control switch:
a. Is necessary on all boilers.
b. Must be used when a boiler is not under continuous supervision.
c. Is a normally open switch.
d. Usually does not require manual resetting.
e. Activates after the safety valve opens.
b. Must be used when a boiler is not under continuous supervision.
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
A leveling 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.
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
A 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
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. Will not result in simultaneous adjustment of air and fuel
e. Eliminates the need for a high limit control
a. Varies electrical current to a modutrol motor
On a multi-burner 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. Operate regardless of where the manual over-ride switch is set.
e. Respond to electrical resistance.
b. Operate continuously when steam demand exceeds boiler capacity
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
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
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 steam pressure
c. Utilizing a closed liquid filled system
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
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
Modulating combustion controls
a. Regulate the steam and feedwater supply
b. Regulate the fuel and air supplies
c. Control the oil atomizer
d. Control the back draft damper
e. Control the draft and feedwater temperature
b. Regulate the fuel and air supplies
Modulating burner controls operate by regulating:
a. Steam flow and fuel flow
b. Fuel temperature and air, flow
c. Fuel flow, air, flow, and feedwater pressure
d. Fuel flow and air, flow
e. Fuel flow and atomizing steam flow
d. Fuel flow and air, flow
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.
c. To shut down the burner if the water temperature rises too high.
The main boiler control device used with an on/off combustion fuel control is a _____ sensing element.
a. Pressure
b. Level
c. Temperature
d. Electronic
e. Pneumatic
a. Pressure
A device found on the pressure side of a boilers 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
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
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 un-adjustable 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
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. Acts as an interlock to ensure minimum damper setting
d. Utilizes a thermal element for its operation
e. Is a normally closed switch.
c. Acts as an interlock to ensure minimum damper setting
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
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. As non-interlocking devices and take no part in a startup
e. On gas fired boilers only.
c. On boilers utilizing a forced draft fan
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
d. Will shut off the fuel to the burner
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. Generate a lower voltage
c. Generate a higher voltage
During the start-up, a boiler equipped with an automatic control system and a 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.
e. Must be closed before ignition
Flame rods:
a. Should be cleaned of deposits regularly.
b. Require frequent filing of electrical contacts to prevent corrosion build-up and failure of the device.
c. Should shut off the fuel within four seconds of flame failure.
d. Are very reliable and maintenance free.
e. Should not be exposed to temperatures above 100°C.
c. Should shut off the fuel within four seconds of flame failure
All flame safeguard devices:
a. Close the main fuel valve in case of pilot flame failure or main burner failure.
b. Require a photoelectric cell.
c. Are limited to temperatures comfortable to the hand.
d. Monitor the pilot flame and main burner simultaneously.
e. Activate an alarm system if flame failure is detected
a. Close the main fuel valve in case of pilot flame failure or main burner failure.
The maximum allowable temperature for the water in a hot water heating boiler is:
a. 100°C b. 150°C c. 121°C d. 170°C e. 250°C.
c. 121°C
A flame scanner:
- Requires a photoelectric cell
- Responds to temperature changes
- Requires a clear line of sight to the flame
- Produces a steady voltage signal
a. 1, 2, 3, 4
b. 2, 3
c. 1, 2, 4
d. 1, 3
e. 2, 3, 4.
d. 1, 3
The “Purple Peeper” scans the boiler furnace for radiation in the _____ range.
a. Visible
b. Ultrasonic
c. Infrared
d. Invisible
e. Ultraviolet
e. Ultraviolet.
The requirement for each automatically fired hot water heating or hot water supply boiler to be protected from over temperature by two temperature-operated controls is stated in:
a. ASME Section I
b. ASME Section IV
c. CSA B-51
d. Alberta Pressure Equipment Safety Regulation
e. Alberta Power Engineers Regulation.
b. ASME Section IV