On a steam boiler with single element feedwater control, the following item is measured:

On a steam boiler with single element feedwater control, the following item is measured:

a) steam flow
b) feedwater flow
c) boiler water level
d) fuel flow
e) feedwater pressure







Answer: C

In a two element feedwater control the following items are measured:

In a two element feedwater control the following items are measured:

a) boiler water level and steam flow
b) feedwater flow and steam flow
c) boiler water level and feedwater flow
d) boiler water level and fuel flow
e) temperature and volume of feedwater



Answer: A

A boiler control transfer or selector station

A boiler control transfer or selector station

a) can be used to manually override automatic control loops
b) can be changed from manual to automatic without balancing
c) is located upstream of the controller in a control loop
d) output is directed to the primary element of a loop
e) must be operated in manual mode for only short periods




Answer: A

With single element feedwater control the level transmitter output is

With single element feedwater control the level transmitter output is

a) received by a final element
b) proportional to drum level
c) sent to a selector station
d) constant regardless of level
e) a function of steam flow




Answer: B

Boiler modulating feedwater control flow rate depends on

Boiler modulating feedwater control flow rate depends on

a) level set point
b) control valve position
c) actual level
d) feedwater pressure
e) set point, level, and valve position





Answer: E

Which of the following is a flame sensing device?

Which of the following is a flame sensing device?

a) thermopile
b) heat sensing control
c) stack relay
d) cut-off valve
e) scanner





Answer: E

The function of a flame failure device is to

The function of a flame failure device is to

a) shut off the fuel supply when the pressure gets too high
b) shut off the fuel when the burner flame goes out
c) shut off the fuel when the fuel temperature is high
d) shut off the feedwater supply to the boiler
e) de-energize the fan and feedwater systems

Answer: B

To operate the type of flame failure device which incorporates a lead sulphide cell, it must receive

To operate the type of flame failure device which incorporates a lead sulphide cell, it must receive

a) heat from flame
b) ultraviolet rays
c) infrared rays
d) heat and radiation
e) a digital signal

Answer: C

A lead sulphide cell is sensitive to IR rays and

A lead sulphide cell is sensitive to IR rays and

a) its resistance to current flow varies inversely with ray emissions
b) its resistance to current does not change during operation
c) will not sense steady IR rays, only pulsating ones
d) will not respond to glowing hot refractory
e) must be replaced at least monthly




Answer: A

A combustion air proving switch

A combustion air proving switch

a) senses O2 content of the air
b) senses flue gas pressure
c) detects O2 in flue gas
d) senses windbox pressure
e) senses air temperature






Answer: D

On a packaged boiler a number of electrical switches connected in series can be categorized as

On a packaged boiler a number of electrical switches connected in series can be categorized as

a) controls
b) interlocks
c) start-up devices
d) programmer controls
e) detectors





Answer: B

The low water fuel cut-off of an unattended automatically fired heating boiler should shut the fuel off if the water level drops below:

The low water fuel cut-off of an unattended automatically fired heating boiler should shut the fuel off if the water level drops below:

a. Below the top row of tubes
b. The furnace tube
c. The lowest visible water level
d. 25 mm above the bottom of the gauge glass
e. The lowest permissible water level





Answer: C

Modulating combustion control will:

Modulating combustion control will:

a. Change air and fuel flow proportionally to steam pressure change
b. Always be at set point when demand is at 50%
c. Alter only the air flow if a selector station is on manual
d. Respond to changes in atmospheric pressure
e. Always be a cascading control system




Answer: A

Modulating pressure controller output:

Modulating pressure controller output:

a. Will shut down and start up the burner
b. Will vary the fuel and air flow to the boiler
c. Will control the temperature of the furnace
d. Is used on small boilers only
e. Is unresponsive to steam flow.





Answer: B

A sudden drop in steam pressure causes

A sudden drop in steam pressure causes

a. a sudden increase in drum level
b. a rapid collapse of steam bubbles in the boiler
c. "shrinkage"
d. a drop in drum level
e. a single element feedwater control to immediately add water to the drum

Answer: A

Overheating of boiler heating surfaces due to low water:

Overheating of boiler heating surfaces due to low water:

a. Is a major cause of boiler failure
b. Will cause a furnace explosion
c. Can be eliminated with a low water fuel cutoff
d. Cannot occur in a hot water boiler
e. Can be prevented with proper water treatment

Answer: A

A hot water boiler low water fuel cutoff:

A hot water boiler low water fuel cutoff:

a. Should be tested weekly during routine boiler operation
b. Cannot be tested during routine boiler operation
c. Cannot be tested
d. Must be located at the lowest permissible water level
e. Must have a normally closed switch





Answer: B

An automatic boiler On-Off or operating control switch has an adjustment for pressure set-point and another for:

An automatic boiler On-Off or operating control switch has an adjustment for pressure set-point and another for:

a. A differential between the two
b. Manual or automatic control
c. For rate of modulation
d. High steam pressure limit
e. Rate of feedback





Answer: A

The low water cut-off of a low pressure steam heating boiler should be tested

The low water cut-off of a low pressure steam heating boiler should be tested

a. By electrician who specializes in boiler controls
b. By lowering the water level, and ensuring the boiler shuts off before the water reaches the bottom of the visible part of the gage glass
c. Several times per shift
d. For correct operation on an annual basis
e. By first shutting off the burner, to prevent boiler damage if the cut-off should fail during testing.

Answer: B

Modulating combustion control on a heating boiler is accomplished by:

Modulating combustion control on a heating boiler is accomplished by:

a. Shutting down or lighting up the burner as pressure or temperature rises or falls
b. Regulating the air flow to control combustion
c. Changing the amount of fuel and air to the burner
d. Opening or closing the forced draft damper
e. Regulating the fuel and feed water flow





Answer: C