DC 3RD CLASS TEST QUESTIONS AND ANSWERS UPDATED 2024/2025 A COMPLETE EXAM SOLUTION ALL ANSWERS GET IT CORRECT DETAILED BEST GRADED A+ FOR PASS

DC 3RD CLASS TEST QUESTIONS AND ANSWERS UPDATED
2024/2025 A COMPLETE EXAM SOLUTION ALL ANSWERS GET
IT CORRECT DETAILED BEST GRADED A+ FOR PASS

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? - CORRECT ANSWERS 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

-6210 -6210

1 Month = 1552.5 pph + .0500



.9500 m = 1552.5 pph

.9500m .9500



1Month = 1,634.21 pph



Gallons per Month = 1634..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? - CORRECT ANSWERS once
per shift



How often do you check the high limit switch? - CORRECT ANSWERS Annually

,DC 3RD CLASS TEST QUESTIONS AND ANSWERS UPDATED
2024/2025 A COMPLETE EXAM SOLUTION ALL ANSWERS GET
IT CORRECT DETAILED BEST GRADED A+ FOR PASS


What is the recommended time for a complete external inspection of a boiler? - CORRECT ANSWERS
once per shift



What is the first thing to do when shutting down a boiler? - CORRECT ANSWERS To turn off the fire



A flow control should be blown down when? - CORRECT ANSWERS once per shift



How often should you check the Low Water Fuel Cut off? - CORRECT ANSWERS once per shift



Why is oil added to the refrigerant? - CORRECT ANSWERS lubrication of the compressor

Keep refrigerant migrating



Recycled and filtered refrigerant can be used where? - CORRECT ANSWERS By the same owner in the
same type of equipment



Data printed on the equipment nameplate would include manufacturer, model, and serial number
and________________? - CORRECT ANSWERS Stamp of approval from commissioning authority



How many BTU's does it take to raise 10 lbs of steam from 40 to 41 degrees? - CORRECT ANSWERS 1
BTU



When working on a boiler, permits should be required? - CORRECT ANSWERS For every shift



How many things do safety controls protect against? - CORRECT ANSWERS Over pressure

Over Heating

Fire side explosions

, DC 3RD CLASS TEST QUESTIONS AND ANSWERS UPDATED
2024/2025 A COMPLETE EXAM SOLUTION ALL ANSWERS GET
IT CORRECT DETAILED BEST GRADED A+ FOR PASS

What chemical compounds in water cause permanent hardness? - CORRECT ANSWERS Calcium Sulfate
and Magnesium Silicate



What chemicals are used to combat corrosion? - CORRECT ANSWERS sodium sulfite and hydrazine



You have boiler water that is found to have a PH of 5. What compound do you add to neutralize? -
CORRECT ANSWERS bases



What produces soft scale? - CORRECT ANSWERS calcium carbonate and magnesium carbonate



With normal oxygen and low alkalinity, what is added to boiler water? - CORRECT ANSWERS
Neutralizing Amines



What is hard forming scale? - CORRECT ANSWERS silica



Which chemicals are used to combat scale? - CORRECT ANSWERS Combined Phosphate Treatment



Which compound is not heat produce? - CORRECT ANSWERS Nitrogen



What takes no actual action in combustion? - CORRECT ANSWERS Nitrogen



With hydroxide present & normal oxygen levels; which chemical will cause problems? - CORRECT
ANSWERS Chlorine



What mechanical device is used to remove scale from Fire Tubes? - CORRECT ANSWERS A Tube Rattler
or Vibrator is used