Carrier 58CTA Installation And Service Instructions Manual page 38

Fig. 53—Orifice Hole
Table 10–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 1000
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
a. Verify unit is running in low heat per Step 4. Place
thermometers in return and supply ducts as close to furnace
as possible. Be sure thermometers do not see radiant heat
BURNER
ORIFICE
A93059
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
from heat exchangers. Radiant heat affects temperature rise
readings. This practice is particularly important with
straight-run ducts.
b. When thermometer readings stabilize, subtract return-air
temperature from supply-air temperature to determine air
temperature rise.
NOTE: If the temperature rise is outside this range, first check:
1.) Gas input for low heat operation.
2.) Derate for altitude if applicable.
3.) Return and supply ducts for excessive restrictions causing static
pressures greater than 0.50-in. wc.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury.
Disconnect 115-v electrical power before changing speed tap.
c. Adjust air temperature rise by adjusting blower speed.
Increase blower speed to reduce temperature rise. Decrease
blower speed to increase temperature rise. For low heat,
speed selection can be low (factory setting), med-low, or
med (5-speed blowers only).
d. Remove thermostat jumpers and release Blower Access
Door Switch.
e. To change motor speed selection for low heat, remove
blower motor lead from control LO-HEAT terminal. (See
Fig. 32.) Select desired blower motor speed lead from 1 of
the other terminals and relocate it to the LO-HEAT
terminal. (See Table 11 for lead color identification).
Reconnect original lead to SPARE terminal.
f. Repeat steps a through e.
→
FURNACE OVERHEATING HAZARD
Failure to properly set temperature rise may cause excessive
furnace temperatures and shorten furnace life.
Recheck temperature rise. It must be within limits specified
on the rating plate. Recommended operation is at the mid-
point of rise range or slightly above.
g. When correct low heat input rate and temperature rise is
achieved, proceed to Step 6.
6. Adjust Manifold Pressure to Obtain High Heat Rate
a. Remove high fire regulator adjustment cap from gas valve
pressure regulator.
b. Manually close blower access door switch.
c. Jumper R, W/W1 and W2 thermostat connections on
control to run furnace in high heat. (See Fig. 32.)
d. Turn high-heat adjusting screw (5/64 hex Allen wrench)
counterclockwise (out) to decrease input rate or clockwise
(in) to increase rate.
Table 11—Speed Selection
COLOR
White
Black
Yellow
Orange†
Blue
Red
* Continuous-blower speed-as shipped default
† Not all models equipped with 5 speed motors
36
SPEED AS SHIPPED
Common BLW
High COOL
Med-High SPARE
Med SPARE
Med-Low HI-HEAT
Low* LO HEAT