289)
289)
Flue gas condensation can be prevented by:
A)
Running a dehumidifier in the room with the furnace.
B)
Passing the combustion gases over a dehumidifier before sending them up the vent.
C)
Using single wall vent.
D)
Using double wall vent.
Answer:
D
Explanation:
290)
290)
The most common airflow problem experienced on air–conditioning systems is:
A)
Excessive airflow caused by high operating voltage.
B)
Low airflow caused by unusually low barometric pressure.
C)
Excessive airflow caused by removing the air filter and not replacing it.
D)
Low airflow caused by dirty or plugged air filters.
Answer:
D
Explanation:
291)
291)
Annual Fuel Utilization Efficiency, AFUE, is:
A)
Calculated by operating the furnace for one hour at the manufacturer’s design condition.
B)
The cost of operating the furnace for an entire heating season.
C)
The efficiency of the furnace for an entire heating season.
D)
Calculated by comparing a customer’s gas bill to the calculated heat loss of their house.
Answer:
C
Explanation:
292)
292)
What is a common symptom of a severely restricted filter drier?
A)
High amp draw on the compressor
B)
It feels hot to the touch.
C)
Frost forming on the outlet
D)
No way to tell without attaching gauges
Answer:
C
Explanation:
76
293)
293)
Which government agency is involved in setting gas–fired equipment standards?
A)
EPA
B)
OSHA
C)
DOE
D)
AHRI
Answer:
C
Explanation:
294)
294)
How does the refrigerant charge affect a system’s subcooling?
A)
Adjusting the refrigerant charge only affects the subcooling if the refrigerant is added on the
high side.
B)
The refrigerant charge does not affect the system subcooling.
C)
Removing refrigerant increases the system subcooling.
D)
Adding refrigerant increases the system subcooling.
Answer:
D
Explanation:
295)
295)
The products of complete combustion of a hydrocarbon gas are:
A)
Carbon, carbon dioxide, and carbon monoxide.
B)
Water, carbon, carbon dioxide, and carbon monoxide.
C)
Water and carbon dioxide.
D)
Carbon dioxide and carbon monoxide.
Answer:
C
Explanation:
296)
296)
When an air–cooled split system operates at low ambient temperatures:
A)
Low ambient controls are necessary for safe operation.
B)
The decreased air density reduces the airflow over the condenser.
C)
Head pressure increases because of the inverse relationship between ambient temperature
and condenser temperature.
D)
System efficiency is increased because of the extra cooling effect of the colder air.
Answer:
A
Explanation:
77
297)
297)
Beginning in 2013, which region in the United States will have the highest minimum AFUE
rating?
A)
The North
B)
The South
C)
The Southwest
D)
All regions share a minimum AFUE rating.
Answer:
A
Explanation:
298)
298)
The products of complete combustion of a hydrocarbon gas are:
A)
Carbon dioxide and carbon monoxide.
B)
Carbon, carbon dioxide, and carbon monoxide.
C)
Water, carbon, carbon dioxide, and carbon monoxide.
D)
Water and carbon dioxide.
Answer:
D
Explanation:
299)
299)
What type of flame is characteristic of incomplete combustion?
A)
Yellow flames
B)
Purple flames
C)
Blue flames
D)
White flames
Answer:
A
Explanation:
300)
300)
Natural gas is:
A)
About the same density as air.
B)
Either lighter or heavier than air depending on the characteristics of the local gas.
C)
Lighter than air.
D)
Heavier than air.
Answer:
C
Explanation:
78
301)
301)
Three broad categories of fuel gases are:
A)
Low pressure, high pressure, and very high pressure.
B)
Hydrocarbon gas, carbon–free gas, and hybrid gas.
C)
Natural, manufactured, and liquified petroleum.
D)
Organic, inorganic, and mixed.
Answer:
C
Explanation:
302)
302)
If carbon monoxide is a product of a reaction resulting in combustion, what can be said about the
combustion?
A)
The integration process was incomplete.
B)
The combustion was incomplete.
C)
The combustion was complete.
D)
The integration process did not occur.
Answer:
B
Explanation:
303)
303)
The three things necessary for combustion are:
A)
Air, gas, and a combustion chamber.
B)
Gas, air, and a burner.
C)
Fuel, oxygen, and heat.
D)
Fuel, heat, and carbon dioxide.
Answer:
C
Explanation:
304)
304)
How do gas furnaces ensure the production of a blue flame?
A)
The use of gas spuds only
B)
The use of gas spuds and a manifold
C)
The use of a manifold only
D)
The use of atmospheric combustion
Answer:
B
Explanation:
79
305)
305)
How is the Annual Fuel Utilization Efficiency (AFUE) efficiency rating determined?
A)
By using the NIST equation for 100 percent efficiency
B)
By comparing new furnace units to the efficiency of older models
C)
By using the NIST equation for 100 percent efficiency minus losses
D)
By multiplying the amount of combustion air with BTU output
Answer:
C
Explanation:
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
306)
306)
Some multisplit systems operate all indoor units from one control while others allow individual
indoor units to operate from their own controls and set points.
Answer:
True
False
Explanation:
307)
307)
It is important when wiring multisplit systems that the indoor units connect to their
corresponding A, B, C, or D terminal block on the outdoor unit.
Answer:
True
False
Explanation:
308)
308)
It is possible for one multi–split indoor unit to heat while another cools.
Answer:
True
False
Explanation:
309)
309)
The smallest capacity VRF outdoor units available generally equal or exceed the largest multisplit
units available.
Answer:
True
False
Explanation:
310)
310)
The wiring connection between the outdoor and indoor unit typically has four wires. One wire
carries power, a second wire carries low voltage communication while a third wire carries both
line voltage power and low voltage communication. A fourth wire is utilized for ground.
Answer:
True
False
Explanation:
311)
311)
Flare connections are used on mini–split systems to avoid oxidation in the lines and also to avoid
heating and destroying the sensitive electronic expansion valves use in the outdoor units.
Answer:
True
False
Explanation:
80
312)
312)
Standard wyes and tees are not used in VRF refrigeration networks as they introduce turbulence
and do not ensure even flow to both branches.
Answer:
True
False
Explanation:
313)
313)
When factory supplied branch joints are not available for VRF refrigerant piping it is permissible
to use standard tees or wyes.
Answer:
True
False
Explanation:
MATCHING. Choose the item in column 2 that best matches each item in column 1.
Match the ventilation system design to its effects on building pressure.
314)
Exhaust
Answer:
B
315)
Supply
Answer:
A
316)
Balanced
Answer:
C
A)
Creates positive building pressure
B)
Creates negative building pressure
C)
Does not affect building pressure
314)
315)
316)
81
Answer Key
Testname: UNIT 41 TO 50
1)
A
2)
D
3)
A
4)
B
5)
C
6)
D
7)
D
8)
E
9)
A
10)
A
11)
B
12)
C
13)
B
14)
D
15)
C
16)
C
17)
E
18)
A
19)
C
20)
C
21)
C
22)
A
23)
C
24)
D
25)
D
26)
A
27)
D
28)
C
29)
B
30)
B
31)
D
32)
C
33)
D
34)
A
35)
B
36)
B
37)
A
38)
C
39)
A
40)
D
41)
B
42)
C
82
Answer Key
Testname: UNIT 41 TO 50
43)
C
44)
B
45)
D
46)
D
47)
B
48)
A
49)
D
50)
A
51)
A
52)
A
53)
B
54)
C
55)
C
56)
D
57)
C
58)
B
59)
A
60)
C
61)
D
62)
D
63)
D
64)
D
65)
A
66)
D
67)
E
68)
D
69)
C
70)
C
71)
A
72)
B
73)
C, D, E
74)
C
75)
A
76)
C
77)
C
78)
B
79)
B
80)
D
81)
C
82)
B
83)
B, C
84)
D
83
Answer Key
Testname: UNIT 41 TO 50
85)
B
86)
A
87)
B
88)
C
89)
B
90)
A
91)
A
92)
B
93)
A
94)
B
95)
B
96)
D
97)
C
98)
B
99)
C
100)
A
101)
B
102)
A
103)
C
104)
D
105)
A
106)
B
107)
B
108)
B
109)
A
110)
B
111)
C
112)
D
113)
A
114)
D
115)
A
116)
C
117)
A
118)
B
119)
B
120)
A
121)
A
122)
C
123)
A
124)
A
125)
D
126)
A
84
Answer Key
Testname: UNIT 41 TO 50
127)
B
128)
A
129)
C
130)
C
131)
A
132)
A
133)
B
134)
D
135)
A
136)
D
137)
B
138)
B
139)
A
140)
A
141)
A
142)
D
143)
D
144)
C
145)
C
146)
B
147)
D
148)
A
149)
A
150)
A
151)
C
152)
C
153)
D
154)
B
155)
B
156)
B
157)
D
158)
C
159)
C
160)
B
161)
B
162)
A
163)
A
164)
B
165)
C
166)
C
167)
D
168)
D
85
Answer Key
Testname: UNIT 41 TO 50
169)
D
170)
A
171)
D
172)
D
173)
A
174)
D
175)
B
176)
C
177)
B
178)
B
179)
A
180)
A
181)
C
182)
A
183)
C
184)
D
185)
B
186)
D
187)
D
188)
C
189)
A
190)
B
191)
B
192)
A
193)
B
194)
D
195)
A
196)
B
197)
B
198)
D
199)
D
200)
B
201)
C
202)
C
203)
C
204)
A
205)
D
206)
D
207)
A, D, E
208)
C
209)
C
210)
A
86
Answer Key
Testname: UNIT 41 TO 50
211)
A
212)
C
213)
A
214)
A
215)
C
216)
C
217)
B
218)
A
219)
A
220)
C
221)
B
222)
D
223)
B
224)
C
225)
B
226)
A
227)
C
228)
B
229)
A
230)
D
231)
A
232)
B
233)
D
234)
C
235)
C
236)
B
237)
C
238)
A
239)
B
240)
D
241)
C
242)
C
243)
B
244)
D
245)
A
246)
D
247)
B
248)
A
249)
D
250)
C
251)
D
252)
B
87
Answer Key
Testname: UNIT 41 TO 50
253)
B
254)
B
255)
B
256)
A
257)
B
258)
C
259)
D
260)
D
261)
B
262)
B
263)
C
264)
A
265)
D
266)
C
267)
C
268)
B
269)
D
270)
C
271)
D
272)
D
273)
D
274)
A
275)
B
276)
C
277)
B
278)
B
279)
B
280)
C
281)
C
282)
D
283)
B
284)
B
285)
B
286)
D
287)
C
288)
D
289)
D
290)
D
291)
C
292)
C
293)
C
294)
D
88
Answer Key
Testname: UNIT 41 TO 50
295)
C
296)
A
297)
A
298)
D
299)
A
300)
C
301)
C
302)
B
303)
C
304)
B
305)
C
306)
TRUE
307)
TRUE
308)
FALSE
309)
TRUE
310)
TRUE
311)
TRUE
312)
TRUE
313)
FALSE
314)
B
315)
A
316)
C
89