Power Engineering 4th Class unit B 3
chapter 5 Questions And Answers
A hot water boiler operating control can be a pressure switch:
Choose one answer.
a. That is normally open
b. That is sensitive to the expansion and contraction of boiler water
c. Utilizing a closed liquid filled system
d. That is sensitive to system steam pressure
e. That is sensitive to boiler steam pressure - ANS c
The type of combustion control frequently used on a small packaged boiler is
Choose one answer.
a. a semi-automatic control
b. a modulating control
c. a proportional control
d. a constant pressure control
e. an on-off control - ANS e
A modulating control steam heating boiler:
Choose one answer.
a. Is always fully automatic
b. Will have a narrow operating pressure range
c. Maintains a steady boiler pressure
d. Will have a constant combustion air, flow rate
e. Cannot be adjusted - ANS c
Prior to a boiler safety valve popping during routine boiler operation:
Choose one answer.
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 - ANS c
An operating control switch for an ON-OFF boiler:
Choose one answer.
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 - ANS a
The most important fitting installed between the operating switch of a steam boiler and the boiler
itself is a
Choose one answer.
a. Tee with a plug
b. Syphon
c. Blowdown valve
d. Test connection for an inspector
e. Pressure gage - ANS b
On a cluster burner, the high fire nozzle will:
Choose one answer.
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 - ANS b
What is the purpose of the high limit control on a hot water boiler?
Choose one answer.
a. To stop the boiler if the water level control fails.
b. To act as a emergency stop for the operator
c. To shut down the burner if the water temperature exceeds 121 deg C.
d. To prevent the pressure in the boiler rising above 210 kPa gage.
e. To prevent excessive pressure from developing - ANS c
The main steam boiler control device used with an on/off combustion fuel control is a _____
sensing element.
Choose one answer.
a. Pressure
b. Level
c. Temperature
d. Flow
e. Pneumatic - ANS a
A flame control switch:
Choose one answer.
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
chapter 5 Questions And Answers
A hot water boiler operating control can be a pressure switch:
Choose one answer.
a. That is normally open
b. That is sensitive to the expansion and contraction of boiler water
c. Utilizing a closed liquid filled system
d. That is sensitive to system steam pressure
e. That is sensitive to boiler steam pressure - ANS c
The type of combustion control frequently used on a small packaged boiler is
Choose one answer.
a. a semi-automatic control
b. a modulating control
c. a proportional control
d. a constant pressure control
e. an on-off control - ANS e
A modulating control steam heating boiler:
Choose one answer.
a. Is always fully automatic
b. Will have a narrow operating pressure range
c. Maintains a steady boiler pressure
d. Will have a constant combustion air, flow rate
e. Cannot be adjusted - ANS c
Prior to a boiler safety valve popping during routine boiler operation:
Choose one answer.
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 - ANS c
An operating control switch for an ON-OFF boiler:
Choose one answer.
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 - ANS a
The most important fitting installed between the operating switch of a steam boiler and the boiler
itself is a
Choose one answer.
a. Tee with a plug
b. Syphon
c. Blowdown valve
d. Test connection for an inspector
e. Pressure gage - ANS b
On a cluster burner, the high fire nozzle will:
Choose one answer.
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 - ANS b
What is the purpose of the high limit control on a hot water boiler?
Choose one answer.
a. To stop the boiler if the water level control fails.
b. To act as a emergency stop for the operator
c. To shut down the burner if the water temperature exceeds 121 deg C.
d. To prevent the pressure in the boiler rising above 210 kPa gage.
e. To prevent excessive pressure from developing - ANS c
The main steam boiler control device used with an on/off combustion fuel control is a _____
sensing element.
Choose one answer.
a. Pressure
b. Level
c. Temperature
d. Flow
e. Pneumatic - ANS a
A flame control switch:
Choose one answer.
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
