Carrier 58SX040 - Manual (Page 6)

START-UP, ADJUSTMENT, AND
SAFETY CHECK
Adjusting Tuning Valve — Before firing the furnace,
adjust the pressure drop through the heat exchanger for
maximum efficiency, following the steps below
A CAUTION
Be sure gas supply to furnace is turned off.
1, Install field-supplied plastic tee between pressure tap
on bottom of gas valve and pressure tube as shown
in Fig. 6.
2 Install second field-supplied plastic tee between
pressure switch and pressure tube from collectoi box
See Fig 6.
3 Connect slope gage to tees (Fig. 6)
4. Close R-W circuit to start inducer motor.
5. Adjust tuning valve to obtain 0.83 ± 0 01 in negative
water column.
6 Remove handle from tuning valve and recheck pres­
sure. Store handle in safe place.
7. Open R-W circuit.
8 Disconnect slope gage
9. Remove plastic tees and reconnect factory pressure
tubes to gas valve and pressure switch.
10 Turn on gas supply to furnace
Ignition System Check — When all connections
have been checked, light the furnace using procedure
outlined on lighting instruction plate attached to furnace
When lighting the furnace for the first time, however,
perform the following additional steps
1 If gas supply was not purged before connecting
furnace, line will be full of air Loosen ground joint
union and allow supply line to purge until gas odor is
detected. Neva purge gas lines into a comhustion
chamber. Immediately upon detection of gas odor,
retighten union. After 5 minutes, light furnace in
accordance with instructions on furnace rating plate.
2 Main burners should light 25 to 75 seconds after pilot.
If main burners do not light within prescribed time
period, adjust pilot flame, allow pilot to cool for
5 minutes, and repeat time check (Fig. 7).
3 Locate pilot adjusting screw on top of valve;
a. Remove cap screw, turn pilot adjusting screw
counterclockwise to decrease burner-on time delay,
or clockwise to increase burner-on time delay.
b. Replace cap screw.
Gas Input
NOTE: Be sure reference pressure tube, combustion-air
and vent pipes, and burner enclosure front are in place
when clocking the gas meter.
1. Deteimine gas input.
a. Turn off all other gas appliances and pilots
b. Measure time (in seconds) for gas meter test dial to
complete one revolution
c Refer to Table 4 for cu ft of gas per hour,
d. Multiply cu ft/ hr by heating value of gas (Btu/ cu ft)
obtained from local gas utility.
EXAMPLE
Btu heating input = Btu/cu ft times cu ft/hr
Heating value of gas = 1070 Btu/cu ft
Time for one revolution of 2-cu-ft dial = 72 sec
Gas rate = 100 cu ft/hr (frbm Table 4)
Btu heating input = 107() x 100 = 107,000 Btuh
e. Measured gas input must not exceed gas input on
unit rating plate.
2. To adjust input rate:
a. Remove burner enclosure front and cap that
conceals adjustment screw for gas valve regulator.
b. Turn adjusting screw either counteiclockwise (out)
to decrease input rate or clockwise to increase rate.
When adjusting input rate, do NOT change mani­
fold pressure more thanO.3 in wg. Make any major
adjustments by changing main burner orifices
(Fig. 7).
Table 4 — Gas Rate in cu ft/hr
SECONDS
FOR ONE
REVOLU­
TION
SIZE OF
TEST DIAL
SECONDS
FOR ONE
SIZE OF
TEST DIAL
1
cu ft
2
cu ft
5
cu ft
REVOLU­
TION
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