DC 3rd Class Test QUESTIONS WITH COMPLETE SOLUTIONS.

DC 3rd Class Test QUESTIONS WITH COMPLETE
SOLUTIONS


1. The component in which liquid vapor by absorbing heat is called?:evapo-
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rator
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2. thebestanswerforanelectricalgroundingmethod?:Metalstakedrive8foot into
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the ground.
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3. A valve should be used for throttling purposes?: Globe
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4. What is the acceptable range for residual sodium sulfite in the boiler main-
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tain?: 30-70
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5. What is the BTU content of a gallon of #4 fuel oil?: 146,000
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6. Whatdoesazeolitewatersoftenersystemuseasameansofregeneration?-
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: brine
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7. What are the 4 steps for a Zeolite Rejuvenation water softener process?: -
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Backwash, Brine, Rinse, Service fi fi fi




8. Where medium temperature liquid found?: Condenser fi fi fi fi fi




9. Where is high temperature vapor found?:At the discharge of the compressor
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or condenser
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10. What stays are used to support the burner chamber in a scotch marine
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boiler?: Diagonal Stays
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11. Whattypeofsafetyvalveisthis?:(Full)Crosbynozzle-typesafetyvalve.Page
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365 BOG
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12. Where do you get superheat reading?:Take suction line pressure fi fi fi fi fi fi fi fi fi




13. Name the wire that connects all component of a system to a physical fi fi fi fi fi fi fi fi fi fi fi fi




ground or water pipe?: Grounding electrode conductor
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14. Where do you get sub-cooling reading?:Take liquid line pressure fi fi fi fi fi fi fi fi fi




Cross reference to temperature using a P/T Chart
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Get liquid line temperature
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Subtract actual temperature from cross referenced temperature fi fi fi fi fi fi




Result is Sub cooling
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,15. On the boilers that have both Quick opening and Screw type blow down
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valves, the Quick opening valve must be located?: closest to the boiler and
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followed by the screw-type valve
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16. HighpressureboilersequippedwithQuickopeningandScrewtypevalves
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areblowndownhow?: ByopeningtheQuickopeningvalvefirstandclosingitLast.
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17. ASME Code defines a slow opening valve as what?:One requiring at least 5
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full 360 degree turns between full open and close position.
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18. A 300 Horsepower boiler operating at 100psi has an average load of 75%
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with 80% condensate return and 5% blow down.The treatment provides a
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chemical which costs $8.75 per gallon, and will treat 600 gallon. Find the
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amountofthechemicalneededforthedayperiod,andthecostofthechemical for a
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30 days period?: Water In = Water Out
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, Makeup + Condensate Return = Evaporator + Blow Down fi fi fi fi fi fi fi fi




Average Evaporator Rate = 300 x 34.5 pph x .75% load = 7762, 50 pph
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1 Month + .8( 7762.50 pph) = 7762.50 pph + 0500 m
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1 Month + 6210 pph = 7762.50 pph + .0500 m
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-6210 -6210 fi




1 Month = 1552.5 pph + .0500
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.9500 m = 1552.5 pph fi fi fi fi




.9500m .9500 fi




1Month = 1,634.21 pph fi fi fi




Gallons per Month = 1634..33 x 24 x 30 = 141, 252.24 gallons per month
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Chemical needed = 141,252.24 gallon / 600 gallon = 235, 40 gallon fi fi fi fi fi fi fi fi fi fi fi




Cost per month = 235, 40 gallon x 8.75 = $2,059.75
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19. During a 24 hours operation how often should you check the water level?- fi fi fi fi fi fi fi fi fi fi fi fi




: once per shift
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20. How often do you check the high limit switch?:Annually
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21. What is the recommended time for a complete external inspection of a
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boiler?: once per shift
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22. What is the first thing to do when shutting down a boiler?:To turn off the fire
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23. A flow control should be blown down when?:once per shift
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24. How often should you check the LowWater Fuel Cut off?:once per shift
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25. Why is oil added to the refrigerant?:lubrication of the compressor
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Keep refrigerant migrating
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26. Recycled and filtered refrigerant can be used where?:By the same owner in fi fi fi fi fi fi fi fi fi fi fi fi




the same type of equipment
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27. Data printed on the equipment nameplate would include manufacturer,
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model, and serial number and
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missioning authority
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