Carrier 140/E Series Installation, Start--Up, Operating, And Service And Maintenance page 37

Table 1 2
- Gas Rate (cu ft./hr)
SECONDS
FOR 1
REVOLUTION
10
11
12
13
14
15
16
17
18
19
2O
21
22
23
24
25
26
27
28
29
3O
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
SIZE OF TEST DIAL
CU FT. 2 CU FT. 5
360 720
327 655
300 600
277 555
257 514
240 480
225 450
212 424
200 400
189 379
180 360
171 343
164 327
157 313
150 300
144 288
138 277
133 267
129 257
124 248
120 240
116 232
113 225
109 218
106 212
103 206
100 200
97 195
95 189
92 185
90 180
88 176
86 172
84 167
82 164
80 160
78 157
76 153
75 150
73 147
CU FT.
1800
1636
1500
1385
1286
1200
1125
1059
1000
947
9OO
857
818
783
75O
72O
692
667
643
621
6OO
581
563
545
529
514
5OO
486
474
462
45O
439
429
419
409
4OO
391
383
375
367
SECONDS
SIZE OF TEST DIAL
FOR 1
REVOLUTION
5O
51
52
53
54
55
56
57
58
59
6O
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96
98
100
102
104
106
108
110
112
116
120
2 Cu FT.
144
141
138
136
133
131
129
126
124
122
12O
116
112
109
106
103
100
97
95
92
90
88
86
84
82
80
78
76
75
74
72
71
69
68
67
65
64
62
60
1 CU FT.
72
71
69
68
67
65
64
63
62
61
60
58
56
54
53
51
50
48
47
46
45
44
43
42
41
40
39
38
38
37
36
35
35
34
33
33
32
31
30
5 Cu FT.
36O
355
346
34O
333
327
321
316
310
3O5
3OO
29O
281
273
265
257
25O
243
237
231
225
22O
214
2O9
2O5
2OO
196
192
188
184
18O
178
173
17O
167
164
161
155
15O
g
c. Adjust air temperature rise by adjusting blower speed. In-
crease 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 remove Blower Access
Door.
e. To change motor speed selection for low heat, remove
blower motor lead from control LO-HEAT terminal.
(See Fig. 33.) Select desired blower motor speed lead
from 1 of the other terminals and relocate it to the LO-
HEAT terminal. (See Table 13 for lead color identifica-
tion). Reconnect original lead to SPARE terminal.
f. Repeat steps a through e.
FURNACE OVERHEATING HAZARD
Failure to follow this caution may result in reduced furnace
life.
Recheck temperature rise. It must be within limits specified
on the rating plate. Recommended operation is at the
midpoint 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. Jumper R, W/WI and W2 thermostat connections on
control to run furnace in high heat. (See Fig. 33.)
c. d. Turn high-heat adjusting screw (3/16-in. (5 mm) or
smaller flat tipped screwdriver) counterclockwise (out)
to decrease input rate or clockwise (in) to increase rate.
d. Re-install high-fire adjustment caps.
e. Leave manifold or similar device connected and proceed
to Step 7.
NOTE: DO NOT set high-heat manifold pressure less than
3.2-In. W.C. or more than 3.8-In. W.C. for natural gas. If
manifold pressure is outside this range, change main burner
orifices.
7. Verify natural gas high heat input rate by clocking meter.
NOTE: Gas valve regulator adjustment caps must be in place for
proper input to be clocked.
a. Turn off all other gas appliances and pilots served by the
meter.
b. Run for 3 minutes in high-heat operation.
c. Measure time (in sec) for gas meter to complete I revolu-
tion and note reading.
d. Refer to Table 12 for cubic ft. of gas per hr.
e. Multiply gas rate cu ft./hr by heating value (Btuh/cu ft.)
to obtain input.
NOTE: Using the 2 cu. ft. or 5 cu. ft. gas meter dial provides
greater accuracy in verifying gas input rate.
37