222)
222)
The electrical disconnect box for a rooftop unit is:
A)
Mounted on the unit.
B)
Not required for rooftop installations.
C)
Mounted on a separate post next to the unit.
D)
Located inside to protect it from the weather.
Answer:
A
Explanation:
223)
223)
In multizone systems with one trunk duct to each zone, what is used to adjust the temperature of
the air?
A)
Fans
B)
Mixing dampers
C)
Outside air
D)
Hot and cold decks
Answer:
D
Explanation:
224)
224)
Constant–air–volume systems can deliver different levels of heating or cooling:
A)
By blocking registers in rooms that are not being used.
B)
By reheating the cool air with strip heat.
C)
By varying the speed of the constant–volume blower.
D)
By using variable–air–volume mixing boxes.
Answer:
D
Explanation:
225)
225)
Why would a preheat coil be used on the energy–recovery wheel?
A)
To prevent frost from forming on the wheel
B)
To dry the intake air
C)
To warm the exhaust air
D)
To prevent moisture transfer to the supply air
Answer:
A
Explanation:
59
226)
226)
The general types of commercial control systems include:
A)
Electric, electronic, and pneumatic.
B)
Low–voltage, line voltage, and millivoltage.
C)
DC millivoltage, DC microamp loop, and AC frequency modulation.
D)
Self–contained and remote.
Answer:
A
Explanation:
227)
227)
Where should the humidity level sensor be placed?
A)
In the dehumidifier
B)
In the outside air supply duct
C)
In the return–air plenum
D)
In the conditioned space
Answer:
D
Explanation:
228)
228)
The primary control for all HVACR functions in a direct digital control (DDC) system is:
A)
A multistage thermostat.
B)
A relay pack.
C)
Not necessary. DDC systems do not use primary controllers.
D)
A computer.
Answer:
D
Explanation:
229)
229)
What is general corrosion?
A)
Corrosion due to attack by metal–eating organisms
B)
Corrosion due to chemical incompatibility between the coil and the refrigerant
C)
Corrosion due to oxidation and chemical attack
D)
Corrosion at the contact point of two types of metal in the presence of an electrolyte
Answer:
C
Explanation:
60
230)
230)
Very large air–conditioning loads are normally handled by:
A)
Rooftop packaged air conditioners.
B)
Packaged terminal air conditioners.
C)
Chillers.
D)
Vertical packaged air conditioners.
Answer:
C
Explanation:
231)
231)
When an air handler has both a DX cooling coil and a hot water heating coil, which coil is located
first in the airstream?
A)
The hot water heating coil
B)
The two coils are in different airstreams.
C)
The DX cooling coil
D)
The air does not travel over the hot water heating coil.
Answer:
A
Explanation:
232)
232)
The three common types of axial fans are:
A)
Forward–curved, backward–curved, and propeller.
B)
Propeller, vane axial, and tube axial.
C)
Clockwise, counterclockwise, and oscillating.
D)
Box fan, window fan, and oscillating.
Answer:
B
Explanation:
233)
233)
What is a HEPA filter?
A)
A very–high–efficiency air filter
B)
A high–efficiency water filter
C)
A filter for heated pans
D)
A filter for a steam heating coil
Answer:
A
Explanation:
61
234)
234)
The most common fan used for moving air across outdoor condenser coils in residential air
conditioning is:
A)
Forward–curved centrifugal.
B)
Backward–curved centrifugal.
C)
Vane axial.
D)
Propeller.
Answer:
D
Explanation:
235)
235)
Rooftop units should be leveled when they are installed so that:
A)
The refrigerant will travel through the system correctly.
B)
The airflow will travel in the right direction through the evaporator.
C)
The oil will return to the compressor.
D)
The condensate can drain properly.
Answer:
D
Explanation:
236)
236)
Gas pressure should be checked at the rooftop valve prior to installation. The gas line pressure for
natural gas in inches of water column should not exceed:
A)
2 psi.
B)
5.0 in WC.
C)
3.5 in WC.
D)
10.5 in WC.
Answer:
D
Explanation:
237)
237)
Under normal operations, some outside air will always be included to:
A)
Maintain the correct humidity levels.
B)
Increase the speed of air circulation.
C)
Prevent excessive levels of CO2 from building up.
D)
Control the temperature more accurately.
Answer:
C
Explanation:
62
238)
238)
What input sensor is found in the fan section?
A)
Supply–air temperature sensor
B)
Filter status toggle switch
C)
Low temperature thermostat
D)
Mixed–air temperature sensor
Answer:
A
Explanation:
239)
239)
Pneumatic control systems:
A)
Use air pressure to modulate control valves.
B)
Are the most recent type of commercial control.
C)
Have no moving parts.
D)
Use electric motors to modulate control valves.
Answer:
A
Explanation:
240)
240)
What is the possible consequence of cutting through a bonded roof to install a vent pipe?
A)
The vent will not vent correctly when passing through a bonded roof.
B)
An electrical short will be created between the vent pipe and the bond on the roof.
C)
The HVAC/R contractor could ultimately be liable for any water damage resulting from
leaks.
D)
Cutting through bonded roofing is safe because the roof is insured.
Answer:
C
Explanation:
241)
241)
Condenser heat reclaiming systems used to heat conditioned space are most frequently found in:
A)
Supermarkets.
B)
Medical buildings.
C)
Warehouses.
D)
High–rise apartments.
Answer:
A
Explanation:
63
242)
242)
The steam grid humidifier works by:
A)
Spraying water through nozzles and atomizing it to steam.
B)
Passing air over a wetted element.
C)
Boiling water in a pan to steam.
D)
Introducing live steam into the air stream though a grid of orifices.
Answer:
D
Explanation:
243)
243)
What is the RPM of a fan that uses a 4 in motor pulley, 8 in fan pulley, and a motor RPM of 1,750?
A)
750
B)
1,250
C)
500
D)
875
Answer:
D
Explanation:
244)
244)
The electrical disconnect can be mounted to the rooftop unit, provided that:
A)
It does not block access to any service panels.
B)
It is mounted inside the unit.
C)
It can easily be removed for service.
D)
It is a general–duty box.
Answer:
A
Explanation:
245)
245)
A device that moves a device such as a valve or damper is called:
A)
A sensor.
B)
An actuator.
C)
A sending unit.
D)
A switch.
Answer:
B
Explanation:
64
246)
246)
The two broad types of fan designs are:
A)
Forward–curved and backward–curved.
B)
Forced draft and induced draft.
C)
Propeller and squirrel cage.
D)
Centrifugal and axial.
Answer:
D
Explanation:
247)
247)
Rooftop units can have the ductwork connected to either:
A)
The bottom or top of the unit.
B)
The main unit or a satellite blower coil.
C)
The bottom or side of the unit.
D)
The top or side of the unit.
Answer:
C
Explanation:
248)
248)
What input sensor is found in the filter section?
A)
Mixed–air temperature sensor
B)
Filter status switch
C)
Low–temperature thermostat
D)
Filter moisture–sensing capillary
Answer:
A
Explanation:
249)
249)
Types of humidifiers used with commercial air–handling equipment include:
A)
Steam grid, steam pan, and direct water spray.
B)
Direct expansion, steam, and hot water.
C)
Direct expansion, chilled water, and steam.
D)
Bypass, atomizing, and wetted media.
Answer:
A
Explanation:
65
250)
250)
Where is the mixed–air temperature measure on an air handler?
A)
In the VAV box where the conditioned air and room air are mixed
B)
Outside by the fresh air intake
C)
In the mixing box
D)
Inside near the return air grille
Answer:
C
Explanation:
251)
251)
Why does a chilled water cooling coil have more rows of coils than a hot water heating coil?
A)
More surface is necessary for dehumidification.
B)
Hot water heating coils can take advantage of radiant heat transfer and cooling coils cannot.
C)
Heat does not travel into cold water as readily as it does into hot water.
D)
Most buildings require more cooling than heating.
Answer:
A
Explanation:
252)
252)
What are differential enthalpy sensors used to control?
A)
The economizer
B)
Second–stage heat
C)
The DX coil
D)
The steam grid
Answer:
A
Explanation:
253)
253)
How is the airflow adjusted on most commercial air handlers?
A)
By adjusting the pitch of the blades on the blower wheel
B)
By adjusting the sheave on an adjustable pulley
C)
By moving the speed tap on the blower motor
D)
By increasing or decreasing the voltage to the fan motor
Answer:
B
Explanation:
66
254)
254)
Cavitation in a water control valve can be caused by:
A)
Installing the control upstream of the coil instead of downstream.
B)
Installing the control downstream of the coil instead of upstream.
C)
Excessively high pressure drop through the valve.
D)
Extremely low pressure drop through the valve.
Answer:
C
Explanation:
255)
255)
The amp draw of a propeller fan will ________ if the airflow leaving the blower is blocked or
restricted.
A)
not change
B)
decrease
C)
increase
D)
Amp draw cannot be determined on a propeller fan.
Answer:
C
Explanation:
256)
256)
What speed will a fan turn if the drive motor is turning at 1,250 RPM, the motor pulley is 4 in in
diameter, and the fan pulley is 8 in in diameter?
A)
625 RPM
B)
The fan RPM cannot be determined using this information.
C)
1,250 RPM
D)
2,500 RPM
Answer:
A
Explanation:
67
257)
257)
To use a fan curve, you need to know:
A)
The RPM and tip speed.
B)
The required CFM and the static pressure the fan must operate against.
C)
The CFM and the RPM.
D)
The horsepower and efficiency.
Answer:
B
Explanation:
258)
258)
When is a forward–curved centrifugal blower motor most likely to draw high amps?
A)
When the airflow leaving the blower is restricted
B)
When the airflow to the blower is restricted
C)
When the motor RPM is set lower than the manufacturer’s specifications
D)
When there is no restriction to the airflow in or out of the blower
Answer:
D
Explanation:
259)
259)
Larger fan coil units are commonly used to condition:
A)
Offices and stores where common air distribution is feasible.
B)
Bedrooms.
C)
Schools.
D)
Hotel and motel rooms.
Answer:
C
Explanation:
260)
260)
Why do air–handling units require field adjustment during the commissioning phase?
A)
Manufacturing errors that affect blower performance are common.
B)
Air–handling units normally do not require field adjustment.
C)
The performance requirements of the blower cannot be determined in advance.
D)
To match the blower performance to the system requirements
Answer:
D
Explanation:
68
261)
261)
The components of a commercial fan coil unit include:
A)
A fan and electric strip heaters.
B)
A compressor, condenser, metering device, and evaporator.
C)
A fan, a water coil, a filter, a fresh air supply, and a control system.
D)
A fan, compressor and condenser.
Answer:
C
Explanation:
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the type of system to the application.
262)
Air conditioning high–rise office
buildings
Answer:
C
263)
Air conditioning single–family
homes
Answer:
B
264)
Maintaining the temperature in a
manufacturing plant
Answer:
A
A)
industrial
B)
residential
C)
commercial
262)
263)
264)
69
Answer Key
Testname: UNIT 71 TO 80
1)
A
2)
D
3)
A
4)
D
5)
A
6)
C
7)
A
8)
A
9)
D
10)
D
11)
C
12)
C
13)
B
14)
A
15)
A
16)
B
17)
A
18)
D
19)
B
20)
D
21)
C
22)
C
23)
A
24)
D
25)
B
26)
D
27)
A
28)
A
29)
B
30)
A
31)
C
32)
D
33)
B
34)
C
35)
B
36)
C
37)
B
38)
B
39)
B
40)
B
41)
C
42)
D
70
Answer Key
Testname: UNIT 71 TO 80
43)
B
44)
C
45)
A
46)
C
47)
B
48)
C
49)
B
50)
D
51)
B
52)
D
53)
A
54)
B
55)
C
56)
B
57)
D
58)
A
59)
B
60)
D
61)
D
62)
B
63)
A
64)
B
65)
C
66)
D
67)
D
68)
B
69)
B
70)
B
71)
B
72)
D
73)
A
74)
C
75)
A
76)
D
77)
D
78)
D
79)
D
80)
B
81)
C
82)
A
83)
B
84)
D
71
Answer Key
Testname: UNIT 71 TO 80
85)
D
86)
B
87)
D
88)
D
89)
A
90)
A
91)
C
92)
B
93)
C
94)
B
95)
C
96)
A
97)
B
98)
D
99)
C
100)
D
101)
A
102)
B
103)
D
104)
B
105)
D
106)
B
107)
B
108)
A
109)
D
110)
A
111)
B
112)
B
113)
C
114)
B
115)
D
116)
D
117)
D
118)
C
119)
A
120)
B
121)
D
122)
D
123)
C
124)
D
125)
D
126)
B
72
Answer Key
Testname: UNIT 71 TO 80
127)
A
128)
D
129)
B
130)
D
131)
C
132)
D
133)
C
134)
C
135)
C
136)
A
137)
C
138)
A
139)
C
140)
C
141)
A
142)
A
143)
C
144)
A
145)
D
146)
D
147)
C
148)
C
149)
D
150)
A
151)
B
152)
A
153)
D
154)
D
155)
D
156)
C
157)
D
158)
C
159)
C
160)
B
161)
B
162)
D
163)
A
164)
A
165)
D
166)
A
167)
C
168)
C
73
Answer Key
Testname: UNIT 71 TO 80
169)
A
170)
B
171)
D
172)
B
173)
A
174)
C
175)
D
176)
B
177)
D
178)
D
179)
D
180)
C
181)
D
182)
D
183)
A
184)
D
185)
A
186)
D
187)
C
188)
B
189)
B
190)
D
191)
B
192)
D
193)
B
194)
A
195)
B
196)
A
197)
A
198)
B
199)
B
200)
A
201)
A
202)
D
203)
A
204)
B
205)
A
206)
D
207)
C
208)
C
209)
A
210)
D
74
Answer Key
Testname: UNIT 71 TO 80
211)
D
212)
B
213)
D
214)
B
215)
B
216)
B
217)
D
218)
C
219)
D
220)
D
221)
C
222)
A
223)
D
224)
D
225)
A
226)
A
227)
D
228)
D
229)
C
230)
C
231)
A
232)
B
233)
A
234)
D
235)
D
236)
D
237)
C
238)
A
239)
A
240)
C
241)
A
242)
D
243)
D
244)
A
245)
B
246)
D
247)
C
248)
A
249)
A
250)
C
251)
A
252)
A
75
Answer Key
Testname: UNIT 71 TO 80
253)
B
254)
C
255)
C
256)
A
257)
B
258)
D
259)
C
260)
D
261)
C
262)
C
263)
B
264)
A
76