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.
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