22
18-CE18D1-1B-EN
Combustion and Input Check
1.
Make sure all gas appliances are off except the furnace.
2.
Clock the gas meter with the furnace operating (determine the
dial rating of the meter) for one revolution.
3.
Match the "Sec" column in the gas flow table with the time
clocked.
4.
Read the "Flow" column opposite the number of seconds clocked.
5.
Use the following factors if necessary:
a.
For 1 Cu. Ft. Dial Gas Flow CFH = Chart Flow Reading ÷ 2
b.
For 1/2 Cu Ft. Dial Gas Flow CFH = Chart Flow Reading ÷ 4
c.
For 5 Cu. Ft. Dial Gas Flow CFH = 10X Chart Flow Reading ÷ 4
6.
Multiply the final figure by the heating value of the gas obtained
from the utility company and compare to the nameplate rating.
This must not exceed the nameplate rating.
Gas Flow in Cubic Feet Per Hour
2 Cubic Foot Dial
Sec.
Flow
Sec.
Flow
Sec.
Flow
Sec.
Flow
10
732
31
236
52
141
86
85
11
666
32
229
53
138
88
83
12
610
33
222
54
136
90
81
13
563
34
215
55
133
94
78
14
523
35
209
56
131
98
75
15
488
36
203
57
128
100
73
16
458
37
198
58
126
104
70
17
431
38
193
59
124
108
68
18
407
39
188
60
122
112
65
19
385
40
183
62
118
116
63
20
366
41
179
64
114
120
61
21
349
42
174
66
111
130
56
22
333
43
170
68
108
140
52
23
318
44
166
70
105
150
49
24
305
45
163
72
102
160
46
25
293
46
159
74
99
170
43
26
282
47
156
76
96
180
41
27
271
48
153
78
94
190
39
28
262
49
149
80
92
200
37
29
253
50
146
82
89
30
244
51
144
84
87
