Carrier 58SC0B Operating Instructions Manual page 33

58SC0B/58SC1B: Installation, Start–Up, Operating and Service and Maintenance Instructions
Low NOx models in the downflow or horizontal positions must use
Table 17 (21,000 BTUh/Burner). See input listed on rating plate.
a. Obtain average yearly gas heat value (at installed altitude) from
local gas supplier.
b. Obtain average yearly gas specific gravity from local gas
supplier.
c. Find installation altitude in
d. Find closest natural gas heat value and specific gravity in
Table 16 or Table 17.
e. Follow heat value and specific gravity lines to point of
intersection to find orifice size and manifold pressure settings for
proper operation.
f. Check and verify burner orifice size in furnace. NEVER
ASSUME ORIFICE SIZE. ALWAYS CHECK AND VERIFY.
NOTE: If orifice hole appears damaged or it is suspected to have been
redrilled, check orifice hole with a numbered drill bit of correct size.
Never redrill an orifice. A burr-free and squarely aligned orifice hole is
essential for proper flame characteristics.
g. Replace orifice with correct size if required by
Table 16, Table 17 and Table
orifices. See EXAMPLE 1.
EXAMPLE 1: (0 to 2000 ft. (0 to 610 M) altitude)
For 22,000 BTUh per burner application use
Heating value = 1000 BTUh/cu ft.
Specific gravity = 0.62
Therefore: Orifice No. 43*
Manifold pressure: 3.7-In. W.C.
*Furnace is shipped with No. 43 orifices.
In this example all main burner orifices are the correct
size and do not need to be changed to obtain proper input rate.
3. Adjust manifold pressure to obtain correct input rate.
a. Turn gas valve ON/OFF switch to OFF.
b. Remove manifold pressure tap plug from gas valve (see
c. Connect a water column manometer or similar device to
manifold pressure tap.
d. Turn gas valve ON/OFF switch to ON.
e. Manually close blower door switch.
f. Set thermostat to call for heat.
g. Remove regulator seal cap and turn regulator adjusting screw
counterclockwise (out) to decrease input rate of clockwise (in) to
increase input rate.
NOTE: DO NOT set manifold pressure less than 3.2-in. w.c. or more
than 3.8-in. w.c. for natural gas at sea level. If manifold pressure is
outside this range, change main burner orifices. Refer to
Table 16, Table 17 and Table 15.
h. Install regulator seal cap.
i. Leave manometer or similar device connected and proceed to
Step 4.
4. Verify natural gas input rate by clocking meter.
NOTE: Gas valve regulator adjustment cap must be in place for proper
input to be clocked.
a. Turn off all other gas appliances and pilots served by the meter.
b. Run furnace for 3 minutes in heating operation.
c. Measure time (in sec) for gas meter to complete 1 revolution and
note reading. The 2 or 5 cubic feet dial provides a more accurate
measurement of gas flow.
d. Refer to Table 16 for cubic ft. of gas per hr.
e. Multiply gas rate (cu ft./hr) by heating value (BTUh/cu ft.) to
obtain input.
f. 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 until correct
input is achieved. Reinstall regulator seal cap on gas valve.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Table 16 or Table 17.
Table 14,
15. Use only factory-supplied
Table 16.
Fig.
Table
Table 15 – Gas Rate (Cu Ft./Hr.)
SIZE OF TEST
SECONDS
FOR 1
1 Cu
REVOLUTION
Ft.
10 360
11 327
12 300
13 277
14 257
15 240
16 225
17 212
18 200
19 189
20 180
21 171
22 164
23 157
24 150
25 144
26 138
27 133
28 129
29 124
30 120
31 116
32 113
33 109
34 106
35 103
21).
36 100
37 97
38 95
39 92
40 90
41 88
42 86
43 84
44 82
45 80
46 78
14,
47 76
48 75
49 73
33
SECONDS
DIAL
FOR 1
2 Cu 5 Cu 1 Cu
REVOLUTION
Ft. Ft. Ft.
720 1800 50 72
655 1636 51 71
600 1500 52 69
555 1385 53 68
514 1286 54 67
480 1200 55 65
450 1125 56 64
424 1059 57 63
400 1000 58 62
379 947 59 61
360 900 60 60
343 857 62 58
327 818 64 56
313 783 66 54
300 750 68 53
288 720 70 51
277 692 72 50
267 667 74 48
257 643 76 47
248 621 78 46
240 600 80 45
232 581 82 44
225 563 84 43
218 545 86 42
212 529 88 41
206 514 90 40
200 500 92 39
195 486 94 38
189 474 96 38
185 462 98 37
180 450 100 36
176 439 102 35
172 429 104 35
167 419 106 34
164 409 108 33
160 400 110 33
157 391 112 32
153 383 116 31
150 375 120 30
147 367
SIZE OF TEST
DIAL
2 Cu 5 Cu
Ft. Ft.
144 360
141 355
138 346
136 340
133 333
131 327
129 321
126 316
124 310
122 305
120 300
116 290
112 281
109 273
106 265
103 257
100 250
97 243
95 237
92 231
90 225
88 220
86 214
84 209
82 205
80 200
78 196
76 192
75 188
74 184
72 180
71 178
69 173
68 170
67 167
65 164
64 161
62 155
60 150