2nd qt refrigeration test review

43. The electrical connections to a central air-conditioning condensing unit typically include a_connection for control

24 Vac

28. Air velocity greater than_fpm at a register may result in a draft

25

33. If the pressure drop across a disposable air filter is more than_% of the pressure drop across the fan, the air filter should be changed.

25

19. The maximum air movement within a room is generally limited to_ to prevent discomfort to the occupants.

25 fpm

48. When a condensing unit is installed at a higher elevation than its evaporator, a U-bend should be put in the Suction line to

assist in oil return

59. A centrifugal compressor chiller's economizer

reduces refrigerant pressure to produce flash gas for liquid line subcooling

52. The ARI standard recommends that chiller evaporators operate at a chilled water temperature of

44°F (7°C)

4. The human comfort level for summer is about_and 50% rh.

75°F (24°C) db

42. Which of the following statements regarding refrigerant line installation is false?

A filter-drier placed in the suction line will prevent condensate from forming.

8. Which of the following statements about air ducts is true?

Air ducts may be made of galvanized sheet metal.

15. Which of the following statements about airflow in duct systems is false?

Airflow compression will be reduced through the use of additional 90° elbows.

12. Which of the following statements about damper controls is false?

All automatic dampers open and close based on the pressure of the conditioned air.

25. Odors and vapors can be removed from the conditioned space

All of the above

41. When installing refrigerant lines,

All of the above

16. Which of the following principles applies when designing a duct system for a building?

All of the above.

20. Smoke from smoke sticks, smoke guns, or smoke candles can be used to

All of the above.

27. Dirt buildup on fan motors can cause

All of the above.

5. If the rooms in a building are tightly sealed, the_

All of the above.

63. Which of the following statements about cooling towers is true?

All of the above.

24. Which of the following is not a step used when balancing a system?

Block all dampers in the ducts and at each room supply.

47. What is the first step in performing maintenance on an air handler?

Clean or replace the air filter.

9. Which of the following statements about duct systems is false?

Ducts in concrete are made by drilling airways with large drill bits and hole saws

87. The overall size of a supply outlet determines a fixture's capacity.

False

93. Registers that pass from unconditioned spaces into conditioned spaces can be sealed to the drywall or subfloor to reduce heat leakage.

False

94. A multiple-blade damper is used primarily in round ducts to control airflow.

False

95. A butterfly damper is used primarily in square or rectangular ducts to restrict or completely shut off airflow to a room or zone.

False

99. Ducts should be installed in the end of a plenum for balanced airflow.

False

3. Which of the following statements about an evaporative cooling system is false?

It decreases the rh level of the air while raising its db temperature.

7. Which of the following statements about air distribution systems is false?

Negative pressure in a building decreases the infiltration at windows and doors.

51. Which of the following statements about rooftop units is false?

RTU parts are purchased individually and assembled on-site.

44. Which of the following is not part of central air-conditioning system service?

Service should begin by removing and cleaning the evaporator,

13. Which of the following statements about fire dampers is false?

Static systems require fire dampers at locations in which fan pressure will be on during a fire.

100. Radial flow fans may be directly driven by the fan motor or driven by a belt and pulley system.

True

75. The space between a false ceiling and a real ceiling may be used as a return air plenum

True

78. A cubic foot of air warmed by a standard heating system will change room temperature more than a cubic foot of air cooled by a standard cooling system,

True

79. As relative humidity decreases, each pound of air will occupy a greater space.

True

82. Heat is released when water vapor condenses.

True

84. When moving cooled air as opposed to moving warmed air, a 30% to 50% airflow increase is usually used

True

85.When sensible heat is removed from air, there is a decrease in dry-bulb temperature

True

86. Air circulation depends on the velocity of the air moving through the supply outlets.

True

88. Ideally, return air ducts would be located both near the floor and the ceiling.

True

89. Return duct inlets should be located at the farthest distance from the supply duct outlets.

True

90. Fresh air intakes are especially important in newer construction or in buildings that have been extensively insulated and weatherproofed.

True

91. Fabric joints can be used to absorb noise caused by the expansion and contraction movements of metal ducts.

True

92. The deflectors in registers are stationary and immovable, maintaining a set direction of airflow.

True

96. When installing a damper, it is helpful to draw a line on the end of the shaft that extends out of the duct to show damper position.

True

97. Proper functioning of a heating or cooling system depends on the duct sizes and damper settings.

True

98. Locating an air handler in a central location minimizes the lengths of the longest supply and return ducts.

True

10. Which of the following statements about duct systems installed in concrete is false?

Upflow furnaces are used with this type of installation

50. A _system is a multi-split, multizone system.

VRF

35. Which of the following statements about air-conditioning systems is false?

When cooling mode is active, the burner is off and the evaporator is heated.

37. Which of the following statements about quick-connect couplings is false?

When the halves are connected, the spring punctures the diaphragm allowing the refrigerant to flow

60. A chiller with a centrifugal compressor has an oil pump that is driven by

a separate motor

22. Soft fabrics, such as drapes, curtains, and fabric-covered furniture, are generally noise

absorbers

23. Tools that allow a technician to create a point in the HVAC system from which to inspect and clean are

access tools

62. The main method of capacity control used by a centrifugal compressor is done by

adjusting the guide vanes

58. The main method of capacity control used by a screw compressor is done by

adjusting the slide valve

31. An instrument used to measure the total airflow of a central HVAC system is a(n)

air handler flowmeter

49. The line set of a ductless system does not typically contain

an occupancy sensor

46. Scheduled periodic maintenance should be performed

annually, before the start of the cooling season

17. Fans used in air distribution systems_

are usually axial flow or radial flow

64. A water valve's main body is most often installed in a system

between the water supply and the condenser

40. The purpose of blank-off plates is to

block off areas of the plenum so all the air passes through the evaporator

67. The process in which some water is intentionally drained for the purpose of reducing certain mineral concentrations in a cooling tower's water is referred to as

blowdown

29. A(n)_test shows how effectively the building envelope minimizes the amount of unconditioned air passing through into conditioned space.

blower door

61. The oil pump used with a chiller's centrifugal compressor

can provide lubrication even before the compressor begins turning

36. A_system includes a single evaporator installed in an air handler cabinet that is connected to a network of ducts.

central air-conditioning

57. To prevent backward flow of refrigerant when the system is shut down, a scroll compressor uses a

check valve

26. One step in preparing a house for blower door testing is to

close exterior windows and doors

72. An anti-icing control monitors the temperature of the

evaporator

55. When a chiller's compressor uses cylinder unloading, compressor power consumption

decreases

30. An instrument used to pressure test a central HVAC system's ductwork is a(n)

duct blaster

45. A common service is to add algaecide tablets to the condensate pan under the

evaporator

76. Residential duct sizing and damper settings must prevent air from traveling too slowly to prevent noise in the system

false

77. As its temperature drops or its pressure rises, air expands to fill a greater space.

false

80. Cold air holds more moisture than warm air.

false

81. A decrease of dry-bulb temperature occurs when sensible heat is added into air.

false

83. An intermittent forced air system provides a more constant temperature in rooms than a continuous blower system.

false

32. An instrument used to measure the airflow through a duct at a given supply or return is a(n)

flow hood

53. To effectively remove noncondensables from a well-maintained chiller, a purge unit will run

for short periods of time

69. A water-filled container on top of a cooling tower that has precision holes through which accumulated water flows onto wet decks is a_ basin.

gravity flow

68. A collection of components used in a cooling tower that pumps water through pipes and out of spray heads along the top of the tower is called a(n)_system

pressured water

2. Air delivered to a room from a supply duct is called_

primary air

1.The heat released when moisture condenses out of the air is_heat

latent

70. A cooling tower that relies on wind and natural convection to blow through the tower to aid evaporation is a(n)_ cooling tower.

natural-draft

18. If there is more return air than supply air in a room, the room will have a_pressure.

negative

65. A water valve that regulates water flow based on the valve's bellow's reaction to high-side pressure is a_ water valve.

pressure

21. Hard, smooth surfaces like walls, ceilings, and floors are noise

reflectors

71. To prevent water from leaking through the opening, a_must be installed between the base rail of a rooftop unit and the top edge of the roof curb.

resilient gasket

73. A fluid that is circulated to absorb heat from a conditioned space is an_refrigerant.

secondary

54. While purge units do help to keep chillers running well, they will release_ on occasion.

small amounts of refrigerant to the atmosphere

34. Ductwork is not required for_system

split

11. Diffusers in air distribution systems

spread the air leaving the duct more uniformly than registers

74. A commercial building can rely on its VRF system to provide the following benefits, except

sufficient ventilation

56. Cylinder unloading is commonly accomplished by holding

the suction valve open

39. The safety controls of comfort cooling systems include

thermal overloads

66. A water valve that regulates water flow to a water-cooled condenser based on the temperature of condenser exhaust water is a _water valve.

thermostatic

38. The operating controls of an air-conditioning system include

thermostats, motor starters, and relays

6. Heat recovery ventilators (HRV,s)_

use a fan to bring in fresh air from the outside

14. Automatic fire dampers should be installed in all ducts in commercial and industrial buildings.

vertical