DC Third Testing Exam
Questions With Revised Correct
Detailed Answers
>Latest Update>>
1. An air handler unit that has hot & cold air ducts connected to (molding
boxes?) located in each building space is called a __________air handler
unit? - ANSWER Dual duct
2. An air handler unit supplies a constant supply air temperature of 55 degree
F to building spaces and includes a coil called _____air handler unit? -
ANSWER A terminal reheat
3. An air handler unit that provides heating, cooling, ventilation, and air
conditioning to more than one building or area and has its cooling &
heating Coil in separate side-by side ducts is called a _______air handling
unit? - ANSWER Multi zone
4. A duplex reciprocating pump runs at 75 rpm. The pump is a 12 x 5 x 12,
Operating with 7% slip. What is the capacity of the pump?
GPM = LANE
231 - ANSWER GPM = 12 x (5 x 5 x 0.7854) x 75 x 2 x (1-0.07)
231
,GPM = 32868.99
231
GPM = 142.29 gpm.
5. What is the area of a steam engine cylinder reading 10 x 24, when the
piston is only travelling at 2/3 of the way? - ANSWER 160 (10 x 24 x
2/3 ) =160
6. In a dual duct air handling system space thermostatic control building
temperature by? - ANSWER Moving the air from the hot & cold duct in
a molding box serving the space
7. A boiler is rated at (86,250 lbs, 88,250 lbs, 96,250 lbs) of steam per hour.
What is the equivalent boiler horsepower? - ANSWER 2500 HP =
86,.5 = 2500 lbs
8. What is the area of a steam engine cylinder reading 10 x 24, when the
piston is only travelling at 2/3 of the way? - ANSWER 160 (10 x 24 x
2/3 ) =160
9. What is the total force acting on a 4 inches diameter safety value disc with
a boiler pressure of 12 psi? - ANSWER 150.79 TF = 150.79
10. The expansion tank on a closed loop system should be located? - ANSWER
On the suction side of the pump
, 11. What is the primary purpose of a crank case heater on a reciprocating
chiller? - ANSWER To prevent refrigeration migration
12. What is meant by the percent of (skip, step, and slip) in a pump? - ANSWER
Percentage of flow compared minimum speed and full speed
e. The difference in theoretical capacity compared to the actual capacity
13. Which of the following types pump can be started with the discharge value
closed? - ANSWER Centrifugal
14 The vertical distance from the center line of the pump up to top level of the
supply tank is called? - ANSWER Static suction head
15. In a multi-zone air handling unit, the zone thermostat controls the zone
temperature by? - ANSWER Dampers that control the air flow from the hot &
cold deck
16. What is meant by a pump becoming steam bound? - ANSWER When the
static pressure at the suction of the pump falls below the vapor pressure
corresponding to its temperature.
17. 62.Which of the following is a positive displacement pump? - ANSWER
Reciprocating
18. The heart of a refrigeration system is the _______? - ANSWER
Compressor
, 19. Refrigerant flow into the evaporator is controlled by ___________? -
ANSWER A metering device
20. What does the whistle on the top of the water column indicating? - ANSWER
High and low water condition
A reciprocating compressor operating with refrigerant R-410 head pressure of
476 psi and a suction pressure of 118 psi. What is the compressor's compression
ratio? - ANSWER 4 = 4:1 2nd choice
The part of the refrigeration system that absorbs heat into the system is
controlled by the ______? - ANSWER Evaporator
A replacement refrigerant for R-12 medium and high temperature refrigeration
application is _____? - ANSWER 134 A
The color for an R-134 a refrigerant cylinder is _______? - ANSWER Light
Blue
The color for an R-410 a refrigerant cylinder is _______? - ANSWER Rose
Which of the following is a hanged joint between two or more _____ furnace and
may be located in the center of the furnace, with _______ than 18-inches an
apart? - ANSWER Adamson ring page BOG
Questions With Revised Correct
Detailed Answers
>Latest Update>>
1. An air handler unit that has hot & cold air ducts connected to (molding
boxes?) located in each building space is called a __________air handler
unit? - ANSWER Dual duct
2. An air handler unit supplies a constant supply air temperature of 55 degree
F to building spaces and includes a coil called _____air handler unit? -
ANSWER A terminal reheat
3. An air handler unit that provides heating, cooling, ventilation, and air
conditioning to more than one building or area and has its cooling &
heating Coil in separate side-by side ducts is called a _______air handling
unit? - ANSWER Multi zone
4. A duplex reciprocating pump runs at 75 rpm. The pump is a 12 x 5 x 12,
Operating with 7% slip. What is the capacity of the pump?
GPM = LANE
231 - ANSWER GPM = 12 x (5 x 5 x 0.7854) x 75 x 2 x (1-0.07)
231
,GPM = 32868.99
231
GPM = 142.29 gpm.
5. What is the area of a steam engine cylinder reading 10 x 24, when the
piston is only travelling at 2/3 of the way? - ANSWER 160 (10 x 24 x
2/3 ) =160
6. In a dual duct air handling system space thermostatic control building
temperature by? - ANSWER Moving the air from the hot & cold duct in
a molding box serving the space
7. A boiler is rated at (86,250 lbs, 88,250 lbs, 96,250 lbs) of steam per hour.
What is the equivalent boiler horsepower? - ANSWER 2500 HP =
86,.5 = 2500 lbs
8. What is the area of a steam engine cylinder reading 10 x 24, when the
piston is only travelling at 2/3 of the way? - ANSWER 160 (10 x 24 x
2/3 ) =160
9. What is the total force acting on a 4 inches diameter safety value disc with
a boiler pressure of 12 psi? - ANSWER 150.79 TF = 150.79
10. The expansion tank on a closed loop system should be located? - ANSWER
On the suction side of the pump
, 11. What is the primary purpose of a crank case heater on a reciprocating
chiller? - ANSWER To prevent refrigeration migration
12. What is meant by the percent of (skip, step, and slip) in a pump? - ANSWER
Percentage of flow compared minimum speed and full speed
e. The difference in theoretical capacity compared to the actual capacity
13. Which of the following types pump can be started with the discharge value
closed? - ANSWER Centrifugal
14 The vertical distance from the center line of the pump up to top level of the
supply tank is called? - ANSWER Static suction head
15. In a multi-zone air handling unit, the zone thermostat controls the zone
temperature by? - ANSWER Dampers that control the air flow from the hot &
cold deck
16. What is meant by a pump becoming steam bound? - ANSWER When the
static pressure at the suction of the pump falls below the vapor pressure
corresponding to its temperature.
17. 62.Which of the following is a positive displacement pump? - ANSWER
Reciprocating
18. The heart of a refrigeration system is the _______? - ANSWER
Compressor
, 19. Refrigerant flow into the evaporator is controlled by ___________? -
ANSWER A metering device
20. What does the whistle on the top of the water column indicating? - ANSWER
High and low water condition
A reciprocating compressor operating with refrigerant R-410 head pressure of
476 psi and a suction pressure of 118 psi. What is the compressor's compression
ratio? - ANSWER 4 = 4:1 2nd choice
The part of the refrigeration system that absorbs heat into the system is
controlled by the ______? - ANSWER Evaporator
A replacement refrigerant for R-12 medium and high temperature refrigeration
application is _____? - ANSWER 134 A
The color for an R-134 a refrigerant cylinder is _______? - ANSWER Light
Blue
The color for an R-410 a refrigerant cylinder is _______? - ANSWER Rose
Which of the following is a hanged joint between two or more _____ furnace and
may be located in the center of the furnace, with _______ than 18-inches an
apart? - ANSWER Adamson ring page BOG
