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OBT3 Updated Exam 2026 WITH Recent Newest Verified And Well
Analyzed Exam Questions (Actual Exam 2026-2027) Correct Detailed
& Verified ANSWERS (100% Accurate Solutions) ALREADY GRADED
A+||NEWEST VERSION Of The Exam Guarantee Pass!!


In the refining process, ____________ separates crude oil in component fractions.
This is followed by __________, which changes the chemical compound.
a) Extraction, distillation
b) Filtration, catalytic cracking
c) Distillation, catalytic cracking
d) Filtration, extraction -ANSWER-C


The minimum standards for the six grades of fuel oil and the two grades of
kerosene are specified by regulation in Canada by which organization?
a) American Society for Testing Materials (ASTM)
b) Canadian Gas Association (CGA)
c) Canadian General Standards Board (CGSB)
d) Canadian Oil Heat Association (COHA) -ANSWER-C


The most common grade of fuel oil used in residential and light commercial
appliances is: a) Kerosene
b) No , 1 fuel oil
c) No. 2 fuel oil
d) No. 4 fuel oil -ANSWER-C

,Which of the following fuel oil characteristics are affected by the temperature of
the fuel oil?
a) Droplet size through the atomizing nozzle.
b) Flow rate through piping or tubing
c)Viscosity
d) All of the listed choices -ANSWER-D




As the degrees of API gravity number increases, the carbon content of the fuel oil
______________ (increases or decreases). -ANSWER-Decreases


True or False:
When properly burned, one gallon of No. 1 fuel oil will produce less heat than
gallon of No. 2 fuel oil. -ANSWER-True


The higher the viscosity of a fuel oil the ___________ (more or less) resistance to
flow -ANSWER-More


The colder the fuel oil the_________ (higher or lower) the viscosity -ANSWER-
Higher


The minimum flash point of No. 2 fuel oil allowed by Standard is:
a) 38°C (100°F)
b) 68°C (155°F)
c) 150°C (300°F)
d) 100°C (212°F) -ANSWER-A

,True or False:
In assessing the distillation test results for a fuel oil, the temperature at which 10
% of the oil is distilled has to be within an acceptable range of the initial boiling
point ( IBP ) as is the case with each successive 10 % increment of distillation. -
ANSWER-True


True or False:
The higher the flash point of fuel oil, the safer it is for storage purposes. -
ANSWER-True


True or False:
The pour point temperature of a fuel oil has no practical significance for an OBT. -
ANSWER-False


A fuel oil with a high temperature cloud point may cause:
a) Excessive corrosion of the appliance and vent.
b) The fuel oil to flow faster through the nozzle
c) Filters, fuel lines or burner parts to become clogged with wax when the fuel is
cold
d) Filters, fuel lines or burner parts to become clogged with clouds when the fuel
is hot. -ANSWER-C


Which of the following causes the formation of sludge at the bottom of fuel oil
storage tanks?
a) Water
b) Carbon

, c) Hydrogen
d) Sulphur -ANSWER-A


True or False:
Used oil or waste derived fuel can be used in any appliance in small amounts. -
ANSWER-False


Which of the following statements is correct? a) Perfect combustion is both
desirable and achievable at every installation.
b) Carbon dioxide (CO2) is a toxic gas.
c) Carbon monoxide (CO) is a toxic gas
d) Carbon is a desired product of complete combustion -ANSWER-C


True or False:
Excess air is necessary for complete combustion of fuel oil. -ANSWER-True




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-Less, CO, Soot


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-Decrease, Increase