DC 3rd Class Test Questions With All
Solved Solutions.
The component in which liquid vapor by absorbing heat is called? - Answer evaporator
the best answer for an electrical grounding method? - Answer Metal stake drive 8 foot into the ground.
A _____ valve should be used for throttling purposes? - Answer Globe
What is the acceptable range for residual sodium sulfite in the boiler maintain? - Answer 30-70
What is the BTU content of a gallon of #4 fuel oil? - Answer 146,000
What does a zeolite water softener system use as a means of regeneration? - Answer brine
What are the 4 steps for a Zeolite Rejuvenation water softener process? - Answer Backwash, Brine,
Rinse, Service
Where medium temperature liquid found? - Answer Condenser
Where is high temperature vapor found? - Answer At the discharge of the compressor or condenser
What stays are used to support the burner chamber in a scotch marine boiler? - Answer Diagonal Stays
What type of safety valve is this? - Answer ( Full) Crosby nozzle-type safety valve. Page 365 BOG
Where do you get superheat reading? - Answer Take suction line pressure
,Name the wire that connects all component of a system to a physical ground or water pipe? - Answer
Grounding electrode conductor
Where do you get sub-cooling reading? - Answer 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? - Answer 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? -
Answer By opening the Quick opening valve first and closing it Last.
ASME Code defines a slow opening valve as what? - Answer 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? - Answer 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? - Answer once per shift
How often do you check the high limit switch? - Answer Annually
What is the recommended time for a complete external inspection of a boiler? - Answer once per shift
What is the first thing to do when shutting down a boiler? - Answer To turn off the fire
A flow control should be blown down when? - Answer once per shift
How often should you check the Low Water Fuel Cut off? - Answer once per shift
Why is oil added to the refrigerant? - Answer lubrication of the compressor
Keep refrigerant migrating
Recycled and filtered refrigerant can be used where? - Answer By the same owner in the same type of
equipment
Solved Solutions.
The component in which liquid vapor by absorbing heat is called? - Answer evaporator
the best answer for an electrical grounding method? - Answer Metal stake drive 8 foot into the ground.
A _____ valve should be used for throttling purposes? - Answer Globe
What is the acceptable range for residual sodium sulfite in the boiler maintain? - Answer 30-70
What is the BTU content of a gallon of #4 fuel oil? - Answer 146,000
What does a zeolite water softener system use as a means of regeneration? - Answer brine
What are the 4 steps for a Zeolite Rejuvenation water softener process? - Answer Backwash, Brine,
Rinse, Service
Where medium temperature liquid found? - Answer Condenser
Where is high temperature vapor found? - Answer At the discharge of the compressor or condenser
What stays are used to support the burner chamber in a scotch marine boiler? - Answer Diagonal Stays
What type of safety valve is this? - Answer ( Full) Crosby nozzle-type safety valve. Page 365 BOG
Where do you get superheat reading? - Answer Take suction line pressure
,Name the wire that connects all component of a system to a physical ground or water pipe? - Answer
Grounding electrode conductor
Where do you get sub-cooling reading? - Answer 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? - Answer 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? -
Answer By opening the Quick opening valve first and closing it Last.
ASME Code defines a slow opening valve as what? - Answer 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? - Answer 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? - Answer once per shift
How often do you check the high limit switch? - Answer Annually
What is the recommended time for a complete external inspection of a boiler? - Answer once per shift
What is the first thing to do when shutting down a boiler? - Answer To turn off the fire
A flow control should be blown down when? - Answer once per shift
How often should you check the Low Water Fuel Cut off? - Answer once per shift
Why is oil added to the refrigerant? - Answer lubrication of the compressor
Keep refrigerant migrating
Recycled and filtered refrigerant can be used where? - Answer By the same owner in the same type of
equipment
