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20 Cards in this Set
- Front
- Back
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The ability of hot air to rise and cool air to fall is an example of what?
1) Conduction 2) Natural Convection 3) Force Air Convection 4) Natural Conduction |
2) Natural Convection
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The flow of unconditioned air from the house into the furnace is called what?
1) Supply Air 2) Combustion Air 3) Return Air 4) Nominal Air |
3) Return Air
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Many different furnace systems exist for all applications in homes. The main difference between Up-flow, Down-Flow, and Horizontal flow is what?
1) The style of heat exchanger 2) The direction of flow of the air through the furnace. 3) The fuel used. 4) Whether it is Natural or Forced air convection |
2) The direction or flow of air through the furnace.
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What are the requirements for combustion?
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Fuel, Oxygen, Heat
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What gases are Natural Gas made from.
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Methane, Ethane (Sometimes Propane is added)
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What is the unit of measurement used for the sale of propane?
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The Gallon
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What does having a specific weight of .6 tell you about natural gas?
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It's lighter then Air. Air has a specific weight of 1.
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A Therm is equal to 100,000 BTU of Heat energy. What is a CCF equal to?
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100 Cubic Feet of fuel
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What is the average heating value of Natural Gas in BTUH?
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1050 BTUH
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At a minimum, how many cu. ft. of air is required to combust 1 cu. ft. of Natural Gas
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10 cu. ft. of Air
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At a minimum, how many cu. ft. of air is required to combust 1 cu. ft. of Propane.
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23.5 Cu. Ft. of Air
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How much excess air is added to the products of combustion for Natural Gas?
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5 Cu. Ft. of Excess Air or 50 percent.
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A flue CO reading of ________ ppm with a single gas analyzer that only detects CO could have a CO Air-free of as high as 400 ppm depending on the amount of excess air in the flue gas.
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235 ppm
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"Confined space" is defined as "and area that is less than ____ cubic feet per 1000 BTUH of all appliances in the space.
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50
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The pressure that is created in the vent system when draft naturally occurs. Negative or Positive
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Negative
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What is required in a masonry chimney when exposed to combustion products from natural gas.
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It must have a fired clay tile liner.
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Where are the regulations for combustion air venting listed for gas burning appliances.
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NFPA 54 (The National Fuel Gas Code)
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When using horizontal ducts or openings to supply combustion air to a confined space, each opening must have a free area of 1 sq. in. per _______ BTUH of combined input from all appliances in the space.
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2000 BTUH
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What is the minimum vertical height for type "B" vents?
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5' above the highest connected draft hood.
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When a furnace has a draft diverter, how much extra dilution air is typically neccessary for proper venting?
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15 cu. feet
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