ABSA 5th Class Final Exam Test 2026\2027.
Where are the return openings located regarding air distribution systems?
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?
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
1, 3, 5
Carbon, which is not combined with hydrogen, is referred to as:
Fixed Carbon
Maximum static pressure in a fuel oil line is approximately:
35 kPa
Combustion of a fuel in a boiler furnace:
should be performed with a minimum of excess air
What is a hydrostatic test?
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?
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
3, 4
In hot water boiler operation the maximum operating temperature should never exceed:
,ABSA 5th Class Final Exam Test 2026\2027.
121 degrees celsius
A substance, which will absorb humidity inside a boiler during dry lay up is:
Activated alumina
When draft is produced by natural means:
cooler air surrounding the boiler increases draft
Coal is composed of the following combustible components:
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
3,4,5
Which grade of oil is the most popular for domestic and small commercial boilers?
Grade 2
The inclined manometer as compared to the U manometer is what?
More accurate.
How can the draft through a natural draft furnace be increased?
Increase the temperature of the stack
The main function of a gas burner is:
provision of O2 - fuel contact
The minimum distance from furnace to oil storage tank is:
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
10,000 - 12,000 volts.
Combustion of a fuel in a boiler furnace should be performed in what conditions?
There should be a minimum of excess air.
What type of oil burner is used when oil is supplied under high pressure?
Mechanical Atomizing Burner
An air atomizing compressor is usually what type?
A rotary type.
Which of the following advantages does oil have over coal as a boiler fuel?
1. requires less storage space
, ABSA 5th Class Final Exam Test 2026\2027.
2. costs less to handle
3. fuel quantity is easier to control
4. burns more cleanly
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?
To allow better boiler warm-ups
What is a manometer used for?
Measure draft
A draft gauge on a furnace indicates the draft in:
mm of water column
A solenoid type fuel gas valve is held close by what?
Fuel pressure
Regarding a burner with 3 fixed capacity nozzles,the secondary and tertiary nozzles are ignited by:
Primary burner
Ethane is a component of natural gas and constitutes a percent volume of:
10-20%
An interrupted pilot does what?
Lights, completes a trial, and extinguishes after the main flame is established.
A very popular packaged boiler gas burner is the:
Ring burner
An intermittent pilot does what?
Lights the main flame and remains on with it.
Before atomization can occur, heavy oils are heated to approximately _____ degrees C.
95
A fuel storage tank must be located a minimum of ____ away from the furnace
2 feet
A refractory burner disadvantage is:
High initial cost
Maximum static pressure in a fuel oil line is approximately what?
35 KPA
When a gas fired burner is burning fuel properly
a) it will have a blue flame with short yellow tips
b) the furnace will pulsate
c) there will be no turbulence
d) it will have a long bright yellow flame
e) the induced draft fan can be shut off
A
In a forced draft system, the furnace pressure is:
Above atmospheric pressure
Where are the return openings located regarding air distribution systems?
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?
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
1, 3, 5
Carbon, which is not combined with hydrogen, is referred to as:
Fixed Carbon
Maximum static pressure in a fuel oil line is approximately:
35 kPa
Combustion of a fuel in a boiler furnace:
should be performed with a minimum of excess air
What is a hydrostatic test?
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?
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
3, 4
In hot water boiler operation the maximum operating temperature should never exceed:
,ABSA 5th Class Final Exam Test 2026\2027.
121 degrees celsius
A substance, which will absorb humidity inside a boiler during dry lay up is:
Activated alumina
When draft is produced by natural means:
cooler air surrounding the boiler increases draft
Coal is composed of the following combustible components:
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
3,4,5
Which grade of oil is the most popular for domestic and small commercial boilers?
Grade 2
The inclined manometer as compared to the U manometer is what?
More accurate.
How can the draft through a natural draft furnace be increased?
Increase the temperature of the stack
The main function of a gas burner is:
provision of O2 - fuel contact
The minimum distance from furnace to oil storage tank is:
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
10,000 - 12,000 volts.
Combustion of a fuel in a boiler furnace should be performed in what conditions?
There should be a minimum of excess air.
What type of oil burner is used when oil is supplied under high pressure?
Mechanical Atomizing Burner
An air atomizing compressor is usually what type?
A rotary type.
Which of the following advantages does oil have over coal as a boiler fuel?
1. requires less storage space
, ABSA 5th Class Final Exam Test 2026\2027.
2. costs less to handle
3. fuel quantity is easier to control
4. burns more cleanly
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?
To allow better boiler warm-ups
What is a manometer used for?
Measure draft
A draft gauge on a furnace indicates the draft in:
mm of water column
A solenoid type fuel gas valve is held close by what?
Fuel pressure
Regarding a burner with 3 fixed capacity nozzles,the secondary and tertiary nozzles are ignited by:
Primary burner
Ethane is a component of natural gas and constitutes a percent volume of:
10-20%
An interrupted pilot does what?
Lights, completes a trial, and extinguishes after the main flame is established.
A very popular packaged boiler gas burner is the:
Ring burner
An intermittent pilot does what?
Lights the main flame and remains on with it.
Before atomization can occur, heavy oils are heated to approximately _____ degrees C.
95
A fuel storage tank must be located a minimum of ____ away from the furnace
2 feet
A refractory burner disadvantage is:
High initial cost
Maximum static pressure in a fuel oil line is approximately what?
35 KPA
When a gas fired burner is burning fuel properly
a) it will have a blue flame with short yellow tips
b) the furnace will pulsate
c) there will be no turbulence
d) it will have a long bright yellow flame
e) the induced draft fan can be shut off
A
In a forced draft system, the furnace pressure is:
Above atmospheric pressure
