DC 3rd Class Test Exam Questions with 100% Complete Solutions, A+

The component in which liquid vapor by absorbing heat is called? evaporator the best answer for an electrical grounding method? Metal stake drive 8 foot into the ground. A _____ valve should be used for throttling purposes? Globe What is the acceptable range for residual sodium sulfite in the boiler maintain? 30-70 What is the BTU content of a gallon of #4 fuel oil? 146,000 What does a zeolite water softener system use as a means of regeneration? brine What are the 4 steps for a Zeolite Rejuvenation water softener process? Backwash, Brine, Rinse, Service Where medium temperature liquid found? Condenser Where is high temperature vapor found? At the discharge of the compressor or condenser What stays are used to support the burner chamber in a scotch marine boiler? Diagonal Stays What type of safety valve is this? ( Full) Crosby nozzle-type safety valve. Page 365 BOG Where do you get superheat reading? Take suction line pressure AD Name the wire that connects all component of a system to a physical ground or water pipe? Grounding electrode conductor Where do you get sub-cooling reading? Take liquid line pressure Cross reference to temperature using a P/T Chart Get liquid line temperature Subtract actual temperature from cross referenced temperature Result is Sub cooling On the boilers that have both Quick opening and Screw type blow down valves, the Quick opening valve must be located? closest to the boiler and followed by the screw-type valve High pressure boilers equipped with Quick opening and Screw type valves are blown down how? By opening the Quick opening valve first and closing it Last. ASME Code defines a slow opening valve as what? One requiring at least 5 full 360 degree turns between full open and close position. A 300 Horsepower boiler operating at 100psi has an average load of 75% with 80% condensate return and 5% blow down. The treatment provides a chemical which costs $8.75 per gallon, and will treat 600 gallon. Find the amount of the chemical needed for the day period, and the cost of the chemical for a 30 days period? Water In = Water Out Makeup + Condensate Return = Evaporator + Blow Down Average Evaporator Rate = 300 x 34.5 pph x .75% load = 7762, 50 pph 1 Month + .8( 7762.50 pph) = 7762.50 pph + 0500 m 1 Month + 6210 pph = 7762.50 pph + .0500 m - 1 Month = 1552.5 pph + .0500 .9500 m = 1552.5 pph .9500m .9500 1Month = 1,634.21 pph Gallons per Month = 1634.21 / 8.33 x 24 x 30 = 141, 252.24 gallons per month Chemical needed = 141,252.24 gallon / 600 gallon = 235, 40 gallon Cost per month = 235, 40 gallon x 8.75 = $2,059.75 During a 24 hours operation how often should you check the water level? once per shift How often do you check the high limit switch? Annually What is the recommended time for a complete external inspection of a boiler? once per shift What is the first thing to do when shutting down a boiler? To turn off the fire