gas exam questions with complete solutions

gas exam questions with complete solutions

List the 3 common purposes of a burner - answer-Mix fuel and air, ignite it, remove
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products of combustion
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Define primary air - answer-air that is mixed with the fuel prior to combustion
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3, Define secondary air - answer-Air that is mixed with the fuel at the point of combustion
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Define atmospheric burner - answer-no mechanical means of adding combustion air
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5, define premix burner - answer-Air and fuel are mixed mechanically prior to
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combustion
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What is one main difference between a fan assist system and a power burner? - answer-
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Fan assist systems are downstream OF COMBUSTION CHAMBER ......
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7, explain turn down ratio - answer-The ratio to which a burner may be throttled or
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modulated...........
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8. what is a nozzle mix burner - answer-Primary air and fuel is mixed at the nozzle under
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pressure
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9, the following type of pilot would have a primary air opening built into it - answer-
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Aerated

10. the following type of pilot system would employ a means of verification prior to
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ignition - answer-Proven type
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11, define Piezoelectric - answer-Mechanical force is applied to a substance which
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generates electricity when compressed/deformed
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12. the source of ignition is present during the entire call for heat is the definition of -
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answer-Intermittent ignition
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13, where electrical current passes through an element which heats to ignite the gas is
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commonly referred to as - answer-HSI
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14. the coefficient of expansion of a metal is its - answer-Its calculated rate of expansion
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in change of temp.
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, 15, the "bulb and bellows" flame sensing device relies on the expansion of what in the
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bulb? - answer-Liquid
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16. if the flame goes out, how does a thermocouple system stop the flow of gas? -
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answer-With no flame, it means of electrical generation is gone the solenoid disengages
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and the flow of gas ceases.
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17, a thermistor is a - answer-Device that has its resistance change based on temp
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18. a flame rectification system uses what as a conductor? - answer-The flame
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19, flame is proven in a rectification system because - answer-The conversion of AC to
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DC
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a fan/limit control has 3 sets of contacts. They are what in correct order - answer-Fan off,
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fan on, high limit
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22. what causes the contacts on a pressuretrol to open? - answer-Setpoint
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23, a probe type low water cut off uses what as the conductor - answer-Water
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24. roll out differ from high limits on account that they... - answer-Roll outs must be
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manually reset and high limits are automatic
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gas fired refrigerators must incorporate what safety? - answer-High limit and CO
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detector
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28. what is a "low boy" furnace? - answer-Burner section is beside the blower
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compartment
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29, what is the purpose of an expansion tank? - answer-To allow for the expansion of
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water in a boiler loop
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30. how does a duct heater differ from a unit heater? - answer-Unit heater do not have
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ductwork
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31, what device maintains setpoint in a steam boiler - answer-Pressuretrol
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33, when making a conversion from LP to NG, the orifices will need to be..... - answer-
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The same, but the pressure will need to change as NG operates off 7.0" WC and LP off
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11.0" WC
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34. when making a conversion from one gas to another, what must be noted on the
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rating plate? - answer-The new type of gas
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