OBT3 COMPREHENSIVE STUDY GUIDE
2026 FULL QUESTIONS AND
SOLUTIONS GRADED A+
◍ Describe the purpose(s) of a combustion chamber.Select one or more:a.rapid
heat up/cool downb.contains the flamec.reflects heat back into the flame.
Answer: a. rapid heat up/cool downb. contains the flamec. reflects heat back
into the flame
◍ Increasing excess air will _______________ (increase or decrease) the
temperature of the flame and ________________ (increase or decrease) the
temperature of the flue gases leaving the heat exchanger..
Answer: excess air will DECREASE temp of the flameINCREASE temp of
flue gas
◍ Chamberless firing usually results in _____ (more or less) heat transfer from
the flame to the heat exchanger and _____ (more or less) noise compared to
firing into a chamber..
Answer: moremore
◍ Hard firebrick is the best material for combustion chambers in residential
appliancesSelect one:TrueFalse.
Answer: false
◍ Cerafelt combustion chamber liners and wet-packs belong to which of the
following material types:Select one:a.Metalb.Hard firebrickc.Soft, insulating
firebrickd.Soft fibre ceramic.
Answer: d. soft fibre ceramic
◍ Which of the following gases is inert and passes through the combustion
reaction without significant effect except for absorbing heat?Select
one:a.Carbon Dioxideb.Oxygenc.Hydrogend.Nitrogen.
, Answer: d. nitrogen
◍ Flame and/or oil spray impingement; oil mist hits the wall, puddles back
into liquid mass that cannot burn properly; incomplete combustion are some
of the effects that too small of a combustion chamber would have on
combustionSelect one:TrueFalse.
Answer: true
◍ What are the two things that must be mixed to have complete
combustion?Select one:a.Fuel oil vapour and combustion airb.Liquid fuel
oil and excess airc.Fuel oil vapour and excess aird.Liquid fuel oil and
combustion air.
Answer: a. fuel oil vapor and combustion air
◍ The purpose of a nozzle in an oil burner is to atomize the oil in order to
prepare it for combustion.Select one:TrueFalse.
Answer: true
◍ Smoke and soot produced by the combustion of oil are unburnt _________
(carbon or hydrogen) atoms which indicates that ___________ (complete or
incomplete) combustion is occurring..
Answer: carbon incomplete
◍ A properly adjusted flame retention head burner has a ________ (shorter or
longer) flame length and a ________ (hotter or cooler) flame temperature
compared to a similar conventional burner..
Answer: shorterhotter
◍ Carbon monoxide is a product of the incomplete combustion of:Select one:a.
Hydrocarbonsb. Sulphurc. Nitrogend. Air.
Answer: a. hydrocarbons
◍ As a general rule, the wall height of combustion chambers should be
_________ times the height of the nozzle to the floor.Select one:a. 4b. 1/2 to
1 1/4c. 2 to 2 1/4d. 1.
Answer: c. c. 2 to 2 1/4
, ◍ The floor area of a combustion chamber in a normal residential appliance
fired at 1 GPH should be:Select one:a. doesn't really matterb. 80 square
inchesc. 100 square inchesd. 90 square inches.
Answer: b. 80 square inches
◍ What are some of the symptoms of carbon monoxide poisoning?Select
one:a.Headaches, nausea, dizzinessb.Disorientation, rapid heart rate, blue
lipsc.Deathd.All of the available choices.
Answer: d. all of the above
◍ Zero smoke levels in the flue gases is an indicator of complete and efficient
combustion.Select one:TrueFalse.
Answer: false
◍ To protect yourself and your customers from carbon monoxide
poisoning:Select one:a. Use an accurate detector to investigate any
indication of COb. Always carry a canary to service callsc. Look for white
flames and ensure there is no soot in the products of combustiond. Ventilate
the structure if you smell carbon monoxide.
Answer: a. use an accurate detector to investigate any indication of CO
◍ Incomplete combustion produces ______ (less or more) heat than complete
combustion and results in the unwanted production of _________________
(carbon dioxide CO2 or carbon monoxide CO) as well as _______ (excess
air or soot) in the flue gases..
Answer: lesscarbon monoxide (CO)soot
◍ cooler flame and combustion gas temperature; droplets won't burn in
suspension as they are not heated fast enough to properly vaporize; possible
incomplete combustion are some of the affects that too large of a
combustion chamber would have on combustionSelect one:TrueFalse.
Answer: true
◍ The size and shape of the combustion chamber is more important for proper
combustion with a conventional high pressure atomizing burner than a flame
retention head burner.Select one:TrueFalse.
2026 FULL QUESTIONS AND
SOLUTIONS GRADED A+
◍ Describe the purpose(s) of a combustion chamber.Select one or more:a.rapid
heat up/cool downb.contains the flamec.reflects heat back into the flame.
Answer: a. rapid heat up/cool downb. contains the flamec. reflects heat back
into the flame
◍ Increasing excess air will _______________ (increase or decrease) the
temperature of the flame and ________________ (increase or decrease) the
temperature of the flue gases leaving the heat exchanger..
Answer: excess air will DECREASE temp of the flameINCREASE temp of
flue gas
◍ Chamberless firing usually results in _____ (more or less) heat transfer from
the flame to the heat exchanger and _____ (more or less) noise compared to
firing into a chamber..
Answer: moremore
◍ Hard firebrick is the best material for combustion chambers in residential
appliancesSelect one:TrueFalse.
Answer: false
◍ Cerafelt combustion chamber liners and wet-packs belong to which of the
following material types:Select one:a.Metalb.Hard firebrickc.Soft, insulating
firebrickd.Soft fibre ceramic.
Answer: d. soft fibre ceramic
◍ Which of the following gases is inert and passes through the combustion
reaction without significant effect except for absorbing heat?Select
one:a.Carbon Dioxideb.Oxygenc.Hydrogend.Nitrogen.
, Answer: d. nitrogen
◍ Flame and/or oil spray impingement; oil mist hits the wall, puddles back
into liquid mass that cannot burn properly; incomplete combustion are some
of the effects that too small of a combustion chamber would have on
combustionSelect one:TrueFalse.
Answer: true
◍ What are the two things that must be mixed to have complete
combustion?Select one:a.Fuel oil vapour and combustion airb.Liquid fuel
oil and excess airc.Fuel oil vapour and excess aird.Liquid fuel oil and
combustion air.
Answer: a. fuel oil vapor and combustion air
◍ The purpose of a nozzle in an oil burner is to atomize the oil in order to
prepare it for combustion.Select one:TrueFalse.
Answer: true
◍ Smoke and soot produced by the combustion of oil are unburnt _________
(carbon or hydrogen) atoms which indicates that ___________ (complete or
incomplete) combustion is occurring..
Answer: carbon incomplete
◍ A properly adjusted flame retention head burner has a ________ (shorter or
longer) flame length and a ________ (hotter or cooler) flame temperature
compared to a similar conventional burner..
Answer: shorterhotter
◍ Carbon monoxide is a product of the incomplete combustion of:Select one:a.
Hydrocarbonsb. Sulphurc. Nitrogend. Air.
Answer: a. hydrocarbons
◍ As a general rule, the wall height of combustion chambers should be
_________ times the height of the nozzle to the floor.Select one:a. 4b. 1/2 to
1 1/4c. 2 to 2 1/4d. 1.
Answer: c. c. 2 to 2 1/4
, ◍ The floor area of a combustion chamber in a normal residential appliance
fired at 1 GPH should be:Select one:a. doesn't really matterb. 80 square
inchesc. 100 square inchesd. 90 square inches.
Answer: b. 80 square inches
◍ What are some of the symptoms of carbon monoxide poisoning?Select
one:a.Headaches, nausea, dizzinessb.Disorientation, rapid heart rate, blue
lipsc.Deathd.All of the available choices.
Answer: d. all of the above
◍ Zero smoke levels in the flue gases is an indicator of complete and efficient
combustion.Select one:TrueFalse.
Answer: false
◍ To protect yourself and your customers from carbon monoxide
poisoning:Select one:a. Use an accurate detector to investigate any
indication of COb. Always carry a canary to service callsc. Look for white
flames and ensure there is no soot in the products of combustiond. Ventilate
the structure if you smell carbon monoxide.
Answer: a. use an accurate detector to investigate any indication of CO
◍ Incomplete combustion produces ______ (less or more) heat than complete
combustion and results in the unwanted production of _________________
(carbon dioxide CO2 or carbon monoxide CO) as well as _______ (excess
air or soot) in the flue gases..
Answer: lesscarbon monoxide (CO)soot
◍ cooler flame and combustion gas temperature; droplets won't burn in
suspension as they are not heated fast enough to properly vaporize; possible
incomplete combustion are some of the affects that too large of a
combustion chamber would have on combustionSelect one:TrueFalse.
Answer: true
◍ The size and shape of the combustion chamber is more important for proper
combustion with a conventional high pressure atomizing burner than a flame
retention head burner.Select one:TrueFalse.
