DC BOILER & STATIONARY Third test Exam 2025–2026 Accurate
Exam Questions and Verified Revised Answers.
Where is medium temperature is 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
What type of safety valve is this?
( Full) Crosby nozzle-type safety valve. Page 365 BOG
Where do you found superheat reading?
Take suction line pressure
Cross reference using a P/T Chart
Get tail coil Temperature
1|Page
,Subtract cross references temperature from tail coil temperature
Result will be superheat
Name the wire that connects all component of a system to a physical ground or
water pipe?
Grounding Electrode Conductor
Where do 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. Page 403 BOG
ASME Code defines a slow opening valve as what?
2|Page
,One requiring at least 5 full 360 degree turns between full open and close
position. Page 374
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
-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
3|Page
, During a 24 hours operation how often should you check the water level?
Once per shift
A 15 psi steam boiler produces 8000 pound of steam per hour. The
Minimum pipe size for the pipe leaving the boiler is___12__inches.
(Density is 0.037 lbs/ft3)
Equation:
D = 12 (C/d/h /.7854)
D = 12 (.037/60) = 3,603.60
D = .ft = 3,927
D = 3.603.,927 = 0.917647058
D = 0.957938963 * 12
D = 11.49 OR 12 "pipe
The boiler steam line is 350 Feet long. During start-up the pipe is heated
From 60 F to 350 F. The 350 F. The pipe wills expand__7.92__inches
Due to the change in temperature
Equation:
(T 1 - T2) x L x .0000065
(350 - 60) x 350 x .0000065
290 x 350 x 12 x .0000065 = 7.92
4|Page
Exam Questions and Verified Revised Answers.
Where is medium temperature is 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
What type of safety valve is this?
( Full) Crosby nozzle-type safety valve. Page 365 BOG
Where do you found superheat reading?
Take suction line pressure
Cross reference using a P/T Chart
Get tail coil Temperature
1|Page
,Subtract cross references temperature from tail coil temperature
Result will be superheat
Name the wire that connects all component of a system to a physical ground or
water pipe?
Grounding Electrode Conductor
Where do 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. Page 403 BOG
ASME Code defines a slow opening valve as what?
2|Page
,One requiring at least 5 full 360 degree turns between full open and close
position. Page 374
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
-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
3|Page
, During a 24 hours operation how often should you check the water level?
Once per shift
A 15 psi steam boiler produces 8000 pound of steam per hour. The
Minimum pipe size for the pipe leaving the boiler is___12__inches.
(Density is 0.037 lbs/ft3)
Equation:
D = 12 (C/d/h /.7854)
D = 12 (.037/60) = 3,603.60
D = .ft = 3,927
D = 3.603.,927 = 0.917647058
D = 0.957938963 * 12
D = 11.49 OR 12 "pipe
The boiler steam line is 350 Feet long. During start-up the pipe is heated
From 60 F to 350 F. The 350 F. The pipe wills expand__7.92__inches
Due to the change in temperature
Equation:
(T 1 - T2) x L x .0000065
(350 - 60) x 350 x .0000065
290 x 350 x 12 x .0000065 = 7.92
4|Page
