Carrier 58SS/DH - Manual (Page 6)

Table 2 — Gas Rate (Cu Ft Per Hr)
SECONDS SIZE OF SECONDS SIZE OF
FOR ONE
TEST DIAL FOR ONE TEST DIAL
REVOLU- 1 2 5 REVOLU- 1 2 5
TION cu ft cu ft cu ft TION cuft cu ft 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 80 225
31 116 232 581 82 44 78 220
32 113 225 563 84 43 76 214
33 109 218 545 86 42 75 209
34 106 212 529 88 41 74 205
35 103 206 514 90 40 80 200
36 100 200 500 92 39 78 196
37 97 195 486 94 38 75 192
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
f. To adjust input rate, remove cap that conceals regu­
lator adjustment. Turn adjusting screw counterclock­
wise (out) to decrease input When adjusting, DO
NOT change manifold pressure more than 0.3 in. wg.
Make any major adjustment by changing main burner
orifices.
HIGH ALTITUDE— Ratings are approved for altitudes
to 2000 ft for all gases. Ratings for altitudes over 2000 ft
are 4% less for each 1000 ft above sea level. (Furnace must
be derated by changing main burner orifices.)
BURNER AND PILOT FLAMES — The main burner
flame should be elear blue, almost transparent. The pilot
flame should be well defined. See Fig. 6.
Temperature Rise — Do not exceed the range of
temperature rise specified on the unit rating plate. Deter­
mine the air temperature rise as follows:
1. Place duct thermometers in return and supply ducts
as near furnace as possible. Be sure thermometers do
not “see” heat element so that radiant heat will not
affect thermometer readings. This is partieularly
important with straight-run duets.
2. When thermometer readings stabilize, subtract return-
air temperature from supply-air temperature to deter­
mine air temperature rise.
3. Adjust air temperature rise by adjusting blower speed.
Increase blower speed to reduce temperature rise.
Decrease blower speed to increase temperature rise.
Thermostat Heat Anticipator Check — Thermo­
stat heat anticipator must be set to match amp draw of
gas valve and eleetrical components in R-W circuit.
Accurate amp draw readings can be obtained at thermo­
stat subbase terminals R & W. Figure 7 illustrates an easy
method of obtaining actual amp draw. Amp reading
should be taken after blower motor has started.
Fig. 7 — Amp Draw Check with Ammeter
Limit Control Safety Check — This control shuts
off the combustion control system and energizes the
circulating-air blower motor if the furnace overheats.
The recommended method of checking the limit con­
trol is to gradually block off the return air after the
furnace has been operating for at least 5 minutes. As soon
as the limit has proven safe, the return air opening should
be unblocked to permit normal air circulation. By
using this method to check the limit control, it can be
established that the limit is functioning properly and will
“fail-safe” if there is a motor failure. The downflow/
horizontal furnaces have a manual reset limit switch
located on blower housing.
Flow-Sensing Switch Safety Check — This con­
trol proves operation of the draft inducer blower. Check
as follows:
1. Turn off 115-volt power to furnace.
2. Remove control door and disconnect inducer motor
lead wires from inducer printed-circuit board.
3. Turn on 115-volt power to furnaee.
4. Close thermostat switch as if making a normal furnace
start. The pilot should light and then cycle off and on.
If main burners do not light, flow-sensing switch is
functioning properly.
5. Turn off 115-volt power to furnace.
6. Reconnect inducer motor wires, replace control door,
turn on 115-volt power.
Draft Safeguard Switch Safety Check — This
control permits safe shutdown of furnace during certain
blocked flue conditions. Check as follows:
1. Disconnect power to furnace and remove vent pipe
from furnace outlet collar. Allow time for vent pipe
to cool before removing.
2. Set room thermostat above room temperature and
restore power to furnace.
3. After normal start-up, allow furnace to operate 2
minutes. Block (100%) flue outlet. Furnace should
cycle off within 2 minutes.
4. Reeonneet vent pipe to furnaee outlet collar.
5. Wait 5 minutes. Reset draft safeguard switch.