Book 1 Chapter 8: Heating Boiler Operating Controls

Question 1

The burner control that continually adjusts the firing rate to maintain the boiler pressure at a constant value is called _________.
A) on-off
B) high-low
C) modulating
D) high limit

Answer 1

C) modulating

Question 2

The name of the second spring that is used to increase the span between cut-in cut-out is the ____________ control.
A) differential
B) high-low
C) mid spring
D) set point

Answer 2

A) differential

Question 3

The simplest type of burner operating control used on low capacity boilers is the ___________.
A) modulating
B) high-low
C) high limit
D) on-off

Answer 3

D) on-off

Question 4

The device used on hot water boilers to maintain the water temperature is the _________.
A) immersion bulb
B) bellows
C) modulator
D) aquastat

Answer 4

D) aquastat

Question 5

The name of the switch used to start or stop the boiler is the _________ switch.
A) selector
B) burner
C) flame control
D) high-low

Answer 5

B) burner

Question 6

If the low air pressure switch is activated it will close the _________.
A) damper
B) main fuel valve
C) pilot gas valve
D) feedwater valve

Answer 6

B) main fuel valve

Question 7

The cut-out pressure setting for a high pressure safety control used to protect a low-pressure steam boiler will be:
A) 103 kPa
B) lower than the cut-out pressure of the operating control
C) just below the popping pressure
D) no higher than 200 kPa

Answer 7

C) just below the popping pressure

Question 8

A manual “high-low” switch should be switched to “high” or “auto”:
A) Prior to ignition of the main flame
B) When the pressure is too low
C) As soon as the main flame has stabilized
D) During the boiler pre-purge
E) When the boiler has been properly warmed up

Answer 8

E) When the boiler has been properly warmed up

Question 9

A levelling indicator is found on:
A) A low water fuel cut-off switch
B) An on-off pressure control switch
C) The casing of a heating boiler
D) A modutrol motor
E) A boiler feedwater pump

Answer 9

B) An on-off pressure control switch

Question 10

In a hot water heating system, the water temperature must never exceed:
A) 121C
B) 100C
C) 80C
D) 110C
E) 60C

Answer 10

A) 121C

Question 11

Quickly closing the main burner manual cock valve during boiler operation should check the:
A) Flame Scanner
B) High gas pressure fuel cut-off
C) Combustion air proving switch
D) Low gas pressure fuel cut-off
E) Low fire interlock switch

Answer 11

B) High gas pressure fuel cut-off

Question 12

Code requirement maximum setting for a high limit control on a steam heating is:
A) 68.9 kPa (10psi)
B) 103 kPa (15psi)
C) 862 kPa (125psi)
D) 207 kPa (30psi)
E) 35 kPa (5psi)

Answer 12

B) 103 kPa (15psi)

Question 13

Modulating burner controls operate by regulating:
A) Steam flow and fuel flow
B) Fuel flow, air flow, and feedwater pressure
C) Fuel temperature and air flow
D) Fuel flow and air flow
E) Fuel flow and atomizing steam flow

Answer 13

D) Fuel flow and air flow

Question 14

The high steam pressure fuel cut-off:
1. Requires an isolation valve for maintenance
2. Is exposed to boiler steam
3. Requires a water seal between it and the boiler
4. Needs to be reset after each operation

A) 1,2
B) 2,3
C) 1,2,3,4
D) 2,3,4
E) 3,4

Answer 14

E) 3,4

Question 15

A high limit control switch:
A) Must be used when a boiler is not under continuous supervision
B) Usually does not require manual resetting
C) Is a normally open switch
D) Is necessary on all boilers
E) Activates after the safety valve opens

Answer 15

A) Must be used when a boiler is not under continuous supervision

Question 16

The main concern of the boiler operator is to operate a boiler:
A) With the water level as high as possible
B) As quietly as possible
C) Without need for water treatment
D) As economically as possible
E) As safely and as efficiently as possible

Answer 16

E) As safely and as efficiently as possible

Question 17

An on-off steam boiler:
A) Cannot operate in a multi-boiler system
B) Will cycle on and off based on a regular timed cycle
C) Must have a low capacity
D) Will maintain a fairly constant steam pressure
E) Operates most efficiently at continuous firing

Answer 17

E) Operates most efficiently at continuous firing

Question 18

A high gas pressure fuel cut-off switch:
A) Must be located upstream of an automatic
B) Is a normally open switch
C) Closes when gas pressure is too high
D) Opens when gas pressure is too high
E) Is never a manual reset device

Answer 18

D) Opens when gas pressure is too high

Question 19

Ideally, the cut out pressure of the high limit control of a steam heating boiler should not exceed:
A) 95% of the safety valve setting
B) 90% of the safety valve setting
C) 100% of the safety valve setting
D) 75% of the safety valve setting
E) 80% of the safety valve setting

Answer 19

B) 90% of the safety valve setting

Question 20

A safeguard is a device or mechanism for ensuring safety. An example of a Safeguard is:
A)Everything listed here
B) High steam pressure fuel cut-off
C) Low gas pressure fuel cut-off switch
D) Low water level fuel cut-off
E) Low air pressure fuel cut-off

Answer 20

A) Everything listed here

Question 21

Operating controls for hot water boilers are not operated by:
A) Liquid expansion
B) Water temperature changes
C) Sensing bulb and capillary tube
D) Steam pressure
E) Bellows controls

Answer 21

D) Steam pressure

Question 22

Common control switches found on low-pressure heating boilers may include:
A) Auto-manual selector switch
B) Low and high fire switches
C) All the switches described here
D) Flame control switch
E) Damper positioning switch

Answer 22

C) All the switches described here

Question 23

The On-Off pressure controller contains two adjustable variables, one is the pressure adjustment and the other is the:
A) Cut-in Lever
B) Operating lever
C) Levelling indicator
D) Pressure bellows
E) Differential adjustment

Answer 23

E)Differential adjustment

Question 24

The modulating fire control system uses _____ to control the combustion process.
A) Variable fuel/air flow
B) Fuel on-off control
C) Air on-off control
D) Fixed fuel flow and variable air flow
E) Fixed air flow and variable fuel flow

Answer 24

A) Variable fuel/air flow

Question 25

Controls found on heating boilers include:
1. Operating controls
2. Pressure relief controls
3. High limit cut-off controls
4. Condensate level controls
5. Low limit cut-off switches

A) 1,2,3
B)2,3,4
C) 1,3,5
D) 3,4,5

Answer 25

C) 1,3,5

Question 26

The high limit control of a steam heating boiler should operate at the:
A) Maximum allowable working pressure
B) Blowdown pressure of the safety valve
C) Between the set pressures of the operating control and safety valve
D) Set pressure of the safety valve
E) Cut-out pressure of the operating control

Answer 26

C) Between the set pressures of the operating control and safety valve

Question 27

Damper position switches are found on boilers with the following burner control systems:
1. On-off control
2. High-low control
3. Modulating control
4. High-limit control

A) 3,4
B) 1,3
C) 1,2
D)2,3
E)4,5

Answer 27

D) 2,3

Question 28

The hot water heating boiler burner control uses the ______ as the sensed variable
A) Boiler steam temperature
B) Drum water level
C) Boiler water pressure
D) Boiler water temperature
E) Feedwater pressure

Answer 28

D)Boiler water temperature

Question 29

The High-Low fire control method requires two pressure controllers, one is called the high-low fire control and the other is called the:
A) High limit control
B) On-off fire control
C) Operating limit fire control
D) Operating limit pressure control
E) Modulating fire control

Answer 29

D) Operating limit pressure control

Question 30

An automatic/manual selector switch is provided on a boiler with the following burner control system
A) High-Low fire control
B) On-Off fire control
C) Operating limit fire control
D) Modulating fire control
E) High limit fire control

Answer 30

D) Modulating fire control

Question 31

If the pressure of the gas supplied to the burner drops below a minimum value the ____ switch will de-energize the fuel valve.
A) Low gas pressure
B) High gas pressure
C) Low water level
D) High limit
E) Low air pressure

Answer 31

A) Low gas pressure

Question 32

The low air pressure cut-off switch can be tested by:
A) Quickly closing the main burner shut-off valve
B) Closing the main gas valve quickly
C) Slowly raising the boiler pressure above the operating setpoint
D) Slowly closing the main gas valve
E) Slowly covering the air supply to the fan

Answer 32

E) Slowly covering the air supply to the fan