Power Engineering 4th Class - B3 Updated
questions and answers
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
A
d. an on/off control - ANS d
VI
A feedwater pipe, where connected to a power boiler, must have:
a. A quick and slow opening stop valve
TU
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 - ANS d
IS
An essential fitting between the boiler and the steam pressure gauge is a:
a. Siphon
OM
b. Gauge glass
c. Gate valve
d. Check valve - ANS a
A variable resistance modulating control:
NA
a. Works in conjunction with a modulating motor
b. Utilizes a mercury switch
c. Senses steam temperature
JP
d. Operates only in the vertical position - ANS 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 - ANS 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 - ANS a
A hot water boiler operating control (Aquastat) may be a pressure switch:
A
a. that is normally open
b. that responds to the expansion and contraction of boiler water
VI
c. operated by a filled system thermometer
d. that is sensitive to steam pressure - ANS c
TU
In steam boiler firing rate control systems, the measured variable is
a. fuel pressure
b. combustion air damper position
IS
c. the steam pressure
d. firing rate control valve position - ANS c
OM
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
NA
d. If the valve is less than 2.5 cm inlet diameter - ANS c
Transparent gauge glasses are lined with mica to:
a. Provide a high temperature seal
JP
b. Increase the strength of the glass
c. Cool the glass
d. Protect the glass - ANS 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 - ANS d
How many blow-off valves are required by most power boilers?
a. Two
b. Three
c. One
A
d. Zero - ANS a
VI
When a boiler steam outlet stop valve is required by code, the preferred style of valve
is:
TU
a. a ball valve
b. a non-rising stem gate valve
c. an outside screw and yoke, rising stem valve
d. a non-rising stem globe valve - ANS c
IS
The purpose of the tee fitting on the piping leading to a boiler steam pressure gauge is
to:
OM
a. Attach a test gauge
b. Blowoff condensate from the pigtail
c. Test a sample of steam for purity
d. Bypass the siphon tube - ANS a
NA
A packaged steam boiler modulating combustion control system will routinely:
a. Maintain drum level within a desired range
b. Maintain flue gas temperature at some set point
JP
c. Maintain boiler steam pressure within a desired range
d. Alter flue flow without changing the air flow - ANS c
Every steam boiler must have a safety valve that is:
a. Connected to the steam or water space of the boiler, without any intervening fitting.
b. Fitted in a vertical position, directly connected to the top of the boiler.
c. Fitted securely to a shut-off valve, which is directly connected to the top of the boiler.
questions and answers
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
A
d. an on/off control - ANS d
VI
A feedwater pipe, where connected to a power boiler, must have:
a. A quick and slow opening stop valve
TU
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 - ANS d
IS
An essential fitting between the boiler and the steam pressure gauge is a:
a. Siphon
OM
b. Gauge glass
c. Gate valve
d. Check valve - ANS a
A variable resistance modulating control:
NA
a. Works in conjunction with a modulating motor
b. Utilizes a mercury switch
c. Senses steam temperature
JP
d. Operates only in the vertical position - ANS 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 - ANS 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 - ANS a
A hot water boiler operating control (Aquastat) may be a pressure switch:
A
a. that is normally open
b. that responds to the expansion and contraction of boiler water
VI
c. operated by a filled system thermometer
d. that is sensitive to steam pressure - ANS c
TU
In steam boiler firing rate control systems, the measured variable is
a. fuel pressure
b. combustion air damper position
IS
c. the steam pressure
d. firing rate control valve position - ANS c
OM
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
NA
d. If the valve is less than 2.5 cm inlet diameter - ANS c
Transparent gauge glasses are lined with mica to:
a. Provide a high temperature seal
JP
b. Increase the strength of the glass
c. Cool the glass
d. Protect the glass - ANS 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 - ANS d
How many blow-off valves are required by most power boilers?
a. Two
b. Three
c. One
A
d. Zero - ANS a
VI
When a boiler steam outlet stop valve is required by code, the preferred style of valve
is:
TU
a. a ball valve
b. a non-rising stem gate valve
c. an outside screw and yoke, rising stem valve
d. a non-rising stem globe valve - ANS c
IS
The purpose of the tee fitting on the piping leading to a boiler steam pressure gauge is
to:
OM
a. Attach a test gauge
b. Blowoff condensate from the pigtail
c. Test a sample of steam for purity
d. Bypass the siphon tube - ANS a
NA
A packaged steam boiler modulating combustion control system will routinely:
a. Maintain drum level within a desired range
b. Maintain flue gas temperature at some set point
JP
c. Maintain boiler steam pressure within a desired range
d. Alter flue flow without changing the air flow - ANS c
Every steam boiler must have a safety valve that is:
a. Connected to the steam or water space of the boiler, without any intervening fitting.
b. Fitted in a vertical position, directly connected to the top of the boiler.
c. Fitted securely to a shut-off valve, which is directly connected to the top of the boiler.
