DC 3rd Class Test Exam Questions with 100% Complete Solutions, A+
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Course
DC 3rd Class
Institution
DC 3rd Class
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 su...
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
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
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