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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 (in cfh)
Table 7, p. 15
with the time clocked.
4. Read the "Flow" column opposite the number of
seconds clocked.
5.
Table 7, p. 15
lists values for a 2 cubic foot dial. For
1, 1/2, or 5 Cu. Ft. dials use the following
conversions:
•
1 Cu. Ft. Dial Gas Flow CFH = Chart Flow
Reading / 2
•
1/2 Cu Ft. Dial Gas Flow CFH = Chart Flow
Reading / 4
•
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
Manual
On-Off
Switch
Regulator Cover Screw
(Adj. screw beneath
this screw)
Vent Post
Outlet
Pressure Tap
Table 7. Gas Flow (in cfh)
Sec.
Flow
Sec.
Flow
8
900
29
248
9
800
30
240
10
720
31
232
11
655
32
225
12
600
33
218
13
555
34
212
14
514
35
206
15
480
36
200
16
450
37
195
17
424
38
189
88-4YCA4001-1A-EN
Figure 10. Burner and Valve
Gas Valve
Manifold
Inlet
Pressure
Tap
Orifice
REF. VIEW
(GAS VALVE)
Sec.
Flow
Sec.
Flow
50
144
82
88
51
141
84
86
52
138
86
84
53
136
88
82
54
133
90
80
55
131
92
78
56
129
94
76
57
126
96
75
58
124
98
73
59
122
100
72
to the nameplate rating. This must not exceed the
nameplate rating.
7. Changes can be made by adjusting the manifold
pressure.
a. Attach a manifold pressure gauge to the Outlet
Pressure Tap.
b. Remove the cover screw on top of the gas valve
to access the manifold pressure adjustment
screw.
c. Turn the adjustment screw in to increase the
gas flow rate, and out to decrease the gas flow
rate using a 3/32" hex wrench or flat-head
screwdriver.
N N o o t t e e : : For manifold pressures and orifice sizes for gas
with other BTU ratings, contact the local gas
utility. Manifold pressure should be 3.5 inches
water column (+ 0.1). Input for natural gas must
n n o o t t exceed the value shown on the rating plate.
Burner
Table 7. Gas Flow (in cfh) (continued)
Sec.
Flow
Sec.
18
400
19
379
20
360
21
343
22
327
23
313
24
300
25
288
26
277
S S t t e e p p 4 4 — — U U n n i i t t I I n n s s t t a a l l l l a a t t i i o o n n
REF. VIEW
(3 Burners)
Flow
Sec.
Flow
39
185
60
120
40
180
62
116
41
176
64
112
42
172
66
109
43
167
68
106
44
164
70
103
45
160
72
100
46
157
74
97
47
153
76
95
Sec.
Flow
104
69
108
67
112
64
116
62
120
60
124
58
128
56
132
54
136
53
15
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