Carrier 58UHV Installation, Start-Up, And Operating Instructions Manual page 23

correct size. Never redrill an orifice. A burr-free and squarely
aligned orifice hole is essential for proper flame characteristics.
e. Move setup switch SW-2 to OFF position after completing
low-heat adjustment.
f. Jumper R and W2 thermostat connections on control center.
(See Fig. 12.) This keeps furnace locked in high-heat
operation.
g. Turn high-heat adjusting screw (5/64 hex Allen wrench)
counterclockwise (out) to decrease input rate or clockwise
(in) to increase rate.
NOTE: DO NOT set high-heat manifold pressure less than 3.2-in.
wc or more than 3.8-in. wc for natural gas. If manifold pressure is
outside this range, change main burner orifices.
h. When correct input is obtained, replace caps that conceal
gas valve regulator adjustment screws. Main burner flame
should be clear blue, almost transparent. (See Fig. 19.)
i. Remove jumper R to W2.
4. Verify natural gas input rate by clocking gas meter.
a. Calculate high-altitude adjustment (if required).
UNITED STATES
At altitudes above 2000 ft, this furnace has been approved
for a 4 percent derate for each 1000 ft above sea level. See
Table 13 for derate multiplier factor and example.
Table 12—Gas Rate (Cu Ft/Hr)
SIZE OF TEST DIAL
SECONDS
FOR 1
1 2 5
REVOLUTION
cu ft cu ft cu ft
10 360 720 1800
11
327 655 1636
12 300 600 1500
13 277 555 1385
14 257 514 1286
15 240 480 1200
16 225 450 1125
17 212 424
1059
18 200 400 100
19 189 379 947
20 180 360 900
21 171 343 857
22 164 327 818
23 157 313 783
24 150 300 750
25 144 288 720
26 138 277 692
27 133 267 667
28 129 257 643
29 124 248 621
30 120 240 600
31 116 232 581
32 113 225 563
33 109 218 545
34 106
212 529
35 103 206 514
36 100 200 500
37 97 195 486
38 95 189 474
39 92 185 462
40 90 180 450
41 88 176 439
42 86 172 429
43 84 167 419
44 82 164 409
45 80 160 400
46 78 157 391
47 76 153 383
48 75 150 375
49 73 147 367
SIZE OF TEST DIAL
SECONDS
FOR 1
1 2 5
REVOLUTION
cu ft cu ft cu ft
50 72 144 360
51 71 141 355
52 69 138 346
53 68 136 340
54 67 133 333
55 65 131 327
56 64 129 321
57 63 126 316
58 62 124 310
59 61 122 305
60 60 120 300
62 58 116 290
64 56 112 281
66 54
109 273
68 53 106 265
70 51 103 257
72 50 100 250
74 48 97 243
76 47 95 237
78 46 92 231
80 45 90 225
82 44 88 220
84 43 86 214
86 42 84 209
88 41 82 205
90 40 80 200
92 39 78 196
94 38 76 192
96 38 75 188
98 37 74 184
100 36 72 180
102 35 71 178
104 35 69 173
106 34 68 170
108 33 67 167
110 33 65 164
112 32 64 161
116 31 62 155
120 30 60 150
Table 13—Altitude Derate Multiplier for U.S.A.
ALTITUDE
(FT) DERATE
0—2000
2001—3000
3001—4000
4001—5000
5001—6000
6001—7000
7001—8000
8001—9000
9001—10,000
* Derate multiplier factor is based on midpoint altitude for altitude range.
EXAMPLE:
85,000 Btuh input furnace installed at 4300 ft.
Furnace Input
Rate at X
Sea Level
85,000 X
CANADA
At installation altitudes from 2000 to 4500 ft, this furnace
must be derated 10 percent by an authorized Gas Conver-
sion Station or Dealer. To determine correct input rate for
altitude, see example above and use 0.90 as derate multi-
plier factor.
b. Check that gas valve adjustment caps are in place for
proper input to be clocked.
c. Obtain yearly gas heat value average for local gas supply.
NOTE: Be sure heating value of gas used for calculations is
correct for your altitude. Consult local gas utility for altitude
adjustment of gas heating value.
d. Check and verify orifice size in furnace. NEVER AS-
SUME THE ORIFICE SIZE. ALWAYS CHECK AND
VERIFY.
e. Turn off all other gas appliances and pilots.
f. Move setup switch SW-2 to ON position. (See Fig. 15.)
This keeps furnace locked in low-heat operation.
g. Jumper R to W/W1.
h. Let furnace run for 3 minutes in low-heat operation.
i. Measure time (in sec) for gas meter to complete 1 revolu-
tion. Note reading.
j. Refer to Table 12 for cubic ft of gas per hr.
k. Multiply gas rate cu ft/hr by heating value (Btu/cu ft).
l. Move setup switch SW-2 to OFF position and jumper R and
W2 thermostat connections. (See Fig. 15.) This keeps
furnace locked in high-heat operation. Repeat items h
through k for high-heat operation.
23
% OF DERATE MULTIPLIER
FACTOR FOR U.S.A.*
0 1.00
8—12 0.90
12—16 0.86
16—20 0.82
20—24 0.78
24—28 0.74
18—32 0.70
32—36 0.66
36—40 0.62
Derate Furnace Input Rate
Multiplier = at Installation
Factor Altitude
0.82 = 69,700