926SB: Installation, Start-up, Operating, Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
59
g. Jumper R and W thermostat connections on control to start
furnace, see Fig. 38.
h. Remove regulator adjustment cap from gas valve pressure
regulator and turn adjusting screw (3/16 or smaller flat-tipped
screwdriver) counterclockwise (out) to decrease input rate or
clockwise (in) to increase input rate, see Fig. 64.
i. When correct input is obtained, replace cap that conceals gas
valve regulator adjustment screws. Main burner flame should be
clear blue, almost transparent, see Fig. 65.
A170140
Fig. 64 – Gas Valve with Tower Pressure Ports
A89020
Fig. 65 – Burner Flame
j. Remove jumpers R to W.
Clocking the Meter
1. Verify natural gas input rate by clocking meter.
NOTE: Contact your HVAC distributor or gas supplier for metric gas
meter tables, if required.
a. Turn off all other gas appliances and pilots served by the meter.
b. Jumper R to W.
c. Run furnace for 3 minutes.
d. Measure time (in sec) for gas meter to complete one revolution
and note reading. The 2 or 5 cubic feet dial provides a more
accurate measurement of gas flow.
e. Refer to Table 25 for cubic ft. of gas per hr.
f. Multiply gas rate cu ft./hr by heating value (BTUh/cu ft.) to
obtain input rate. If clocked rate does not match required input
from Step 1, increase manifold pressure to increase input or
decrease manifold pressure to decrease input. Repeat steps b
through e of Step 1 until correct input is achieved. Re-install
regulator seal cap on gas valve.
g. Jumper R to W. This keeps furnace locked in heat operation.
Repeat items d through g for heat operation.
h. Remove jumpers R to W.
BURNER FLAME
BURNER
MANIFOLD
Table 25 – Gas Rate (CU ft./hr)
SEC.
FOR 1
REV.
SIZE OF TEST DIAL
SEC.
FOR 1
REV.
SIZE OF TEST DIAL
1 Cu
Ft.
2 Cu
Ft.
5
Cu Ft.
1 Cu
Ft.
2 Cu
Ft.
5 Cu
Ft.
10 360 720 1800 50 72 144 360
11 327 655 1636 51 71 141 355
12 300 600 1500 52 69 138 346
13 277 555 1385 53 68 136 340
14 257 514 1286 54 67 133 333
15 240 480 1200 55 65 131 327
16 225 450 1125 56 64 129 321
17 212 424 1059 57 63 126 316
18 200 400 1000 58 62 124 310
19 189 379 947 59 61 122 305
20 180 360 900 60 60 120 300
21 171 343 857 62 58 116 290
22 164 327 818 64 56 112 281
23 157 313 783 66 54 109 273
24 150 300 750 68 53 106 265
25 144 288 720 70 51 103 257
26 138 277 692 72 50 100 250
27 133 267 667 74 48 97 243
28 129 257 643 76 47 95 237
29 124 248 621 78 46 92 231
30 120 240 600 80 45 90 225
31 116 232 581 82 44 88 220
32 113 225 563 84 43 86 214
33 109 218 545 86 42 84 209
34 106 212 529 88 41 82 205
35 103 206 514 90 40 80 200
36 100 200 500 92 39 78 196
37 97 195 486 94 38 76 192
38 95 189 474 96 38 75 188
39 92 185 462 98 37 74 184
40 90 180 450 100 36 72 180
41 88 176 439 102 35 71 178
42 86 172 429 104 35 69 173
43 84 167 419 106 34 68 170
44 82 164 409 108 33 67 167
45 80 160 400 110 33 65 164
46 78 157 391 112 32 64 161
47 76 153 383 116 31 62 155
48 75 150 375 120 30 60 150
49 73 147 367
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