Carrier 58MXA 170 Series Installation, Start-Up, And Operating Instructions Manual page 49

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 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
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
Disconnect 115-v electrical power before changing speed tap.
4. To change blower motor speed selections for heating mode,
remove blower motor lead from control HEAT terminal. (See
Fig. 31.) Select desired blower motor speed lead from 1 of the
other motor leads and relocate it to HEAT terminal. See Table
13 for lead color identification. Reconnect original lead on
SPARE terminal.
Follow this same procedure for proper selection of COOL
speed selection.
ADJUST BLOWER OFF DELAY (HEAT MODE)
The blower off delay has 4 adjustable settings from 90 sec to 180
sec. (See Table 14.) The blower off delay jumpers are located on
the furnace control (See Fig. 31). To change the blower off delay
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
124 29 58 145
Table 13—Speed Selector
COLOR
Black
Yellow (When Present)
Blue
Red
White
setting, move the jumper from one set of pins on the control to the
pins used for the desired blower off delay. Factory blower off
delay setting is 120 sec.
Table 14—Blower Off Delay Jumper Positions
PINS 1 AND 2
Time (in sec) 90
SET THERMOSTAT HEAT ANTICIPATOR
When using a nonelectronic thermostat, the thermostat heat
anticipator must be set to match the amp draw of the electrical
components in R-W circuit. Accurate amp draw readings can be
obtained at thermostat subbase terminals R and W. Fig. 60
illustrates the easy method of obtaining actual amp draw. The amp
reading should be taken after blower motor has started and furnace
is heating. Connect ammeter wires as shown in Fig. 60. The
thermostat anticipator should NOT be in the curcuit while mea-
suring current. If thermostat has no subbase, the thermostat must
be disconnected from R and W wires during current measurement.
See thermostat manufacturer's instructions for adjusting heat
anticipator and for varying heating cycle length.
For an electronic thermostat, set cycle rate for 3 cycles per hour.
Step 6—Check Safety Controls
This section covers the safety controls that must be checked before
the installation is complete. The flame sensor, gas valve, and
pressure switch were all checked in the Start-up procedure section
as part of normal operation.
CHECK PRIMARY LIMIT CONTROL
This control shuts off gas control system and energizes air-
circulating blower motor if furnace overheats. Recommended
method of checking this limit control is to gradually block off
return air after furnace has been operating for a period of at least
5 minutes. As soon as limit control has shut off burners, return-air
opening should be unblocked to permit normal air circulation. By
using this method to check limit control, it can be established that
limit is functioning properly and operates if there is a restricted
return-air duct or motor failure. If limit control does not function
during this test, cause must be determined and corrected.
CHECK PRESSURE SWITCH
This control proves operation of draft inducer. Check switch
operation as follows:
1. Turn off 115-v power to furnace.
2. Remove outer furnace door and disconnect inducer motor
from wire harness.
3. Turn on 115-v power to furnace.
4. Set thermostat to "call for heat" and wait 1 minute. When
pressure switch is functioning properly, hot surface igniter
should NOT glow, and control status code LED flashes a
Status Code 31. If hot surface igniter glows when inducer
49
FACTORY-
SPEED SHIPPED
CONNECTION
High Cool
Medium High Spare
Medium Low Heat
Low Fan
Common C
OM
2 AND 3 3 AND 4 4 AND 5
120 150 180