2025 update DC Third testing questions and answers
2026\2027 A+ Grade
The component in which liquid vapor by absorbing heat is called?
- correct answer Evaporator
Select the best answer electrical grounding method?
- correct answer Metal stake drive 8 foot into the ground.
A _____ valve should be used for throttling purpose?
- correct answer Globe
What is the acceptable range for residual sodium sulfite in the boiler maintain?
- correct answer 30-70
What is the BTU content of a gallon of #4?
- correct answer 146,000
What does a zeolite water softener system use as a means of regeneration?
- correct answer Brine
What are the 4 steps for a Zeolite Rejuvenation water softener process?
- correct answer Back wash
Backwash, brine, rinse, service
Where is medium temperature is liquid found?
- correct answer Condenser
Where is high temperature vapor found?
- correct answer At the discharge of the compressor or condenser
,What stays are used to support the burner chamber in a scotch marine boiler?
- correct answer Diagonal Stays
What type of safety valve is this?
- correct answer ( Full) Crosby nozzle-type safety valve. Page 365 BOG
What type of safety valve is this?
- correct answer ( Full) Crosby nozzle-type safety valve. Page 365 BOG
Where do you found superheat reading?
- correct answer Take suction line pressure
Cross reference using a P/T Chart
Get tail coil Temperature
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?
- correct answer Grounding Electrode Conductor
Where do get sub-cooling reading?
- correct 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?
- correct 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?
- correct answer By opening the Quick opening valve first and closing it Last. Page 403 BOG
ASME Code defines a slow opening valve as what?
- correct answer 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?
- correct 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
2026\2027 A+ Grade
The component in which liquid vapor by absorbing heat is called?
- correct answer Evaporator
Select the best answer electrical grounding method?
- correct answer Metal stake drive 8 foot into the ground.
A _____ valve should be used for throttling purpose?
- correct answer Globe
What is the acceptable range for residual sodium sulfite in the boiler maintain?
- correct answer 30-70
What is the BTU content of a gallon of #4?
- correct answer 146,000
What does a zeolite water softener system use as a means of regeneration?
- correct answer Brine
What are the 4 steps for a Zeolite Rejuvenation water softener process?
- correct answer Back wash
Backwash, brine, rinse, service
Where is medium temperature is liquid found?
- correct answer Condenser
Where is high temperature vapor found?
- correct answer At the discharge of the compressor or condenser
,What stays are used to support the burner chamber in a scotch marine boiler?
- correct answer Diagonal Stays
What type of safety valve is this?
- correct answer ( Full) Crosby nozzle-type safety valve. Page 365 BOG
What type of safety valve is this?
- correct answer ( Full) Crosby nozzle-type safety valve. Page 365 BOG
Where do you found superheat reading?
- correct answer Take suction line pressure
Cross reference using a P/T Chart
Get tail coil Temperature
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?
- correct answer Grounding Electrode Conductor
Where do get sub-cooling reading?
- correct 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?
- correct 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?
- correct answer By opening the Quick opening valve first and closing it Last. Page 403 BOG
ASME Code defines a slow opening valve as what?
- correct answer 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?
- correct 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
