OBT3 Ch. 7 & 11 Questions with
Guaranteed Pass Solutions 2026
Updated.
Describe the purpose(s) of a combustion chamber.
Select one or more:
a.
rapid heat up/cool down
b.
contains the flame
c.
reflects heat back into the flame - Answer a. rapid heat up/cool down
b. contains the flame
c. 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 flame
INCREASE 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
more
more
Hard firebrick is the best material for combustion chambers in residential appliances
Select one:
True
False - Answer false
Cerafelt combustion chamber liners and wet-packs belong to which of the following material
types:
Select one:
a.
Metal
b.
,Hard firebrick
c.
Soft, insulating firebrick
d.
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 Dioxide
b.
Oxygen
c.
Hydrogen
d.
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 combustion
Select one:
True
False - Answer true
What are the two things that must be mixed to have complete combustion?
Select one:
a.
Fuel oil vapour and combustion air
b.
Liquid fuel oil and excess air
c.
Fuel oil vapour and excess air
d.
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:
True
False - 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 shorter
hotter
Carbon monoxide is a product of the incomplete combustion of:
Select one:
a. Hydrocarbons
b. Sulphur
c. Nitrogen
d. 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. 4
b. 1/2 to 1 1/4
c. 2 to 2 1/4
d. 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 matter
b. 80 square inches
c. 100 square inches
Guaranteed Pass Solutions 2026
Updated.
Describe the purpose(s) of a combustion chamber.
Select one or more:
a.
rapid heat up/cool down
b.
contains the flame
c.
reflects heat back into the flame - Answer a. rapid heat up/cool down
b. contains the flame
c. 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 flame
INCREASE 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
more
more
Hard firebrick is the best material for combustion chambers in residential appliances
Select one:
True
False - Answer false
Cerafelt combustion chamber liners and wet-packs belong to which of the following material
types:
Select one:
a.
Metal
b.
,Hard firebrick
c.
Soft, insulating firebrick
d.
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 Dioxide
b.
Oxygen
c.
Hydrogen
d.
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 combustion
Select one:
True
False - Answer true
What are the two things that must be mixed to have complete combustion?
Select one:
a.
Fuel oil vapour and combustion air
b.
Liquid fuel oil and excess air
c.
Fuel oil vapour and excess air
d.
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:
True
False - 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 shorter
hotter
Carbon monoxide is a product of the incomplete combustion of:
Select one:
a. Hydrocarbons
b. Sulphur
c. Nitrogen
d. 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. 4
b. 1/2 to 1 1/4
c. 2 to 2 1/4
d. 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 matter
b. 80 square inches
c. 100 square inches
