Power Engineering 4th Class -
B3 Questions and Complete
Solutions Graded A+
The type of firing rate control frequently used on small capacity packaged boilers is:
a. a modulating control
b. a high fuel pressure cut-off
c. a constant pressure control
d. an on/off control - Answer: d
A feedwater pipe, where connected to a power boiler, must have:
a. A quick and slow opening stop valve
b. A stop valve only
c. A check valve between the stop valve and the boiler
d. A check valve, with a stop valve between the check valve and the boiler - Answer: d
An essential fitting between the boiler and the steam pressure gauge is a:
a. Siphon
b. Gauge glass
c. Gate valve
d. Check valve - Answer: a
A variable resistance modulating control:
a. Works in conjunction with a modulating motor
,b. Utilizes a mercury switch
c. Senses steam temperature
d. Operates only in the vertical position - Answer: a
If a boiler produces steam at a higher rate than the rate of steam consumption, and this condition goes
unchecked
a. soot will develop on the fireside
b. the boiler efficiency will drop
c. the boiler will overheat
d. the boiler will over-pressurize - Answer: d
A boiler feedwater isolation valve:
a. May be a globe valve, provided water enters below the disc
b. Should be located close to the feedwater pump
c. Must be a globe valve
d. Is used to isolate the deaerator - Answer: a
A hot water boiler operating control (Aquastat) may be a pressure switch:
a. that is normally open
b. that responds to the expansion and contraction of boiler water
c. operated by a filled system thermometer
d. that is sensitive to steam pressure - Answer: c
In steam boiler firing rate control systems, the measured variable is
a. fuel pressure
, b. combustion air damper position
c. the steam pressure
d. firing rate control valve position - Answer: c
Do not open the safety valve with the test lever:
a. If the valve is not vented to the roof
b. If there are more than two safety valves on the boiler
c. If the pressure is less than 75% working pressure
d. If the valve is less than 2.5 cm inlet diameter - Answer: c
Transparent gauge glasses are lined with mica to:
a. Provide a high temperature seal
b. Increase the strength of the glass
c. Cool the glass
d. Protect the glass - Answer: d
A boiler with a single safety valve has a maximum allowable working pressure of 1000 kPa. What is the
maximum boiler pressure permissible when the safety valve is blowing?
a. 1100 kPa
b. 1030 kPa
c. 1000 kPa
d. 1060 kPa - Answer: d
How many blow-off valves are required by most power boilers?
a. Two
B3 Questions and Complete
Solutions Graded A+
The type of firing rate control frequently used on small capacity packaged boilers is:
a. a modulating control
b. a high fuel pressure cut-off
c. a constant pressure control
d. an on/off control - Answer: d
A feedwater pipe, where connected to a power boiler, must have:
a. A quick and slow opening stop valve
b. A stop valve only
c. A check valve between the stop valve and the boiler
d. A check valve, with a stop valve between the check valve and the boiler - Answer: d
An essential fitting between the boiler and the steam pressure gauge is a:
a. Siphon
b. Gauge glass
c. Gate valve
d. Check valve - Answer: a
A variable resistance modulating control:
a. Works in conjunction with a modulating motor
,b. Utilizes a mercury switch
c. Senses steam temperature
d. Operates only in the vertical position - Answer: a
If a boiler produces steam at a higher rate than the rate of steam consumption, and this condition goes
unchecked
a. soot will develop on the fireside
b. the boiler efficiency will drop
c. the boiler will overheat
d. the boiler will over-pressurize - Answer: d
A boiler feedwater isolation valve:
a. May be a globe valve, provided water enters below the disc
b. Should be located close to the feedwater pump
c. Must be a globe valve
d. Is used to isolate the deaerator - Answer: a
A hot water boiler operating control (Aquastat) may be a pressure switch:
a. that is normally open
b. that responds to the expansion and contraction of boiler water
c. operated by a filled system thermometer
d. that is sensitive to steam pressure - Answer: c
In steam boiler firing rate control systems, the measured variable is
a. fuel pressure
, b. combustion air damper position
c. the steam pressure
d. firing rate control valve position - Answer: c
Do not open the safety valve with the test lever:
a. If the valve is not vented to the roof
b. If there are more than two safety valves on the boiler
c. If the pressure is less than 75% working pressure
d. If the valve is less than 2.5 cm inlet diameter - Answer: c
Transparent gauge glasses are lined with mica to:
a. Provide a high temperature seal
b. Increase the strength of the glass
c. Cool the glass
d. Protect the glass - Answer: d
A boiler with a single safety valve has a maximum allowable working pressure of 1000 kPa. What is the
maximum boiler pressure permissible when the safety valve is blowing?
a. 1100 kPa
b. 1030 kPa
c. 1000 kPa
d. 1060 kPa - Answer: d
How many blow-off valves are required by most power boilers?
a. Two
