UNIT 50 REVIEW QUESTIONS ANSWER KEY GO BACK TO INDEX
50-1) Discuss the origin of natural gas.
50-2) List the three broad categories of fuel gasses.
50-3) Complete this table of fuel gas characteristics.
Gas Heat
Specific
50-4) What are the products of complete combustion of a hydrocarbon gas?
50-5) What are the products of incomplete combustion of a hydrocarbon gas?
50-6) Why are LP gasses considered more hazardous than natural gas?
50-7) Describe the two types of flames and their characteristics.
Yellow and blue. Yellow, called luminous combustion, is from incomplete
50-8) Describe the gas combustion process as it applies to a gas furnace.
Gas passes through an orifice and the gas stream travels into the burner
50-9) Explain the causes of flue gas condensation and how it can be stopped.
Flue gas condensation occurs when the water vapor in the flue gas is cooled
50-10) Explain the cause of soot formation on the heat exchanger and how it can be
stopped.
50-11) Explain how carbon monoxide is formed.
50-12) Discuss furnace combustion air requirements.
50-13) List agencies that establish standards for gas furnaces.
DOE, AGA, NIST, NSF, UL, CSA
50-15) Explain AFUE.
50-16) What is the minimum AFUE rating for a new furnace in the United States?
50-17) Which agencies both set equipment standards and test equipment.
50-19) What can be done to minimize the pollutants produced by a gas furnace?
50-20) What is the purpose of excess air in furnace combustion?