Where are the return openings located regarding air distribution systems? - ANS Return air openings are located on inner walls.
The minimum temperature of the water used in a hydrostatic test of a boiler cannot be less than what temperature? - ANS 20 degrees Celsius
Which ...
Latest ABSA 5th Class Exam Questions
And Answers
Where are the return openings located regarding air distribution systems? - ANS Return
air openings are located on inner walls.
The minimum temperature of the water used in a hydrostatic test of a boiler cannot be less than
what temperature? - ANS 20 degrees Celsius
Which of the following are causes of pressure explosions?
1. effects of corrosion
2. weak pilot flame
3. stressed material due to heating too quickly
4. insufficient purge
5. scale and sludge build-up - ANS 1, 3, 5
Carbon, which is not combined with hydrogen, is referred to as: - ANS Fixed Carbon
Maximum static pressure in a fuel oil line is approximately: - ANS 35 kPa
Combustion of a fuel in a boiler furnace: - ANS should be performed with a minimum of
excess air
What is a hydrostatic test? - ANS A way in which pressure vessels can be tested for
strength and leaks.
How often do burner and fan motors which uses standard bearing normally require lubrication? -
ANS Yearly
On a hot water boiler, the pressure differential between the operating pressure and the safety
relief valve set pressure must be (at a minimum):
,1. 25% of operating pressure
2. 125% of operating pressure
3. 69 kPa
4. 25% of the safety relief valve set pressure - ANS 3, 4
In hot water boiler operation the maximum operating temperature should never exceed: - ANS
121 degrees celsius
A substance, which will absorb humidity inside a boiler during dry lay up is: - ANS
Activated alumina
When draft is produced by natural means: - ANS cooler air surrounding the boiler
increases draft
Coal is composed of the following combustible components: - ANS Carbon, hydrogen,
Sulphur
Which of the following are causes of furnace explosions?
1. main fuel valve closed when the burner flame is lost
2. insufficient purge
3. burners lit from hot refractory
4. effects of corrosion
5. admission of fuel before ignition source - ANS 3,4,5
Which grade of oil is the most popular for domestic and small commercial boilers? - ANS
Grade 2
The inclined manometer as compared to the U manometer is what? - ANS More accurate.
How can the draft through a natural draft furnace be increased? - ANS Increase the
temperature of the stack
The main function of a gas burner is: - ANS provision of O2 - fuel contact
The minimum distance from furnace to oil storage tank is: - ANS 2 feet
, One of the main component of an electric ignition system is the step-up transformer which takes
120 V and boosts it to _____ volts - ANS 10,000 - 12,000 volts.
Combustion of a fuel in a boiler furnace should be performed in what conditions? - ANS
There should be a minimum of excess air.
What type of oil burner is used when oil is supplied under high pressure? - ANS
Mechanical Atomizing Burner
An air atomizing compressor is usually what type? - ANS A rotary type.
Which of the following advantages does oil have over coal as a boiler fuel?
1. requires less storage space
2. costs less to handle
3. fuel quantity is easier to control
4. burns more cleanly - ANS All of the above
In a boiler burner with 3 fixed capacity nozzles,the intermediate and high burner nozzles have
higher capacities than the primary burner nozzle for what reason? - ANS To allow better
boiler warm-ups
What is a manometer used for? - ANS Measure draft
A draft gauge on a furnace indicates the draft in: - ANS mm of water column
A solenoid type fuel gas valve is held close by what? - ANS Fuel pressure
Regarding a burner with 3 fixed capacity nozzles,the secondary and tertiary nozzles are ignited
by: - ANS Primary burner
Ethane is a component of natural gas and constitutes a percent volume of: - ANS 10-20%
An interrupted pilot does what? - ANS Lights, completes a trial, and extinguishes after the
main flame is established.
A very popular packaged boiler gas burner is the: - ANS Ring burner
An intermittent pilot does what? - ANS Lights the main flame and remains on with it.
Before atomization can occur, heavy oils are heated to approximately _____ degrees C. - ANS
95
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