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880TB/881TB: Installation, Start–Up, Operating and Service and Maintenance Instructions
d. Measure time (in sec) for gas meter to complete 1 revolution and
note reading. The 2 or 5 cubic feet dial provides a more accurate
measurement of gas flow.
e. Refer to
Table 18
for cubic ft. of gas per hr.
f. Multiply gas rate cu ft./hr by heating value (BTUh/cu ft.) to
obtain input. If clocked rate does not match required input from
Step 1, increase manifold pressure to increase input or decrease
manifold pressure to decrease input. Repeat steps b through e
until correct low-heat input is achieved. Re-install low heat
regulator seal cap on gas valve.
g. Jumper R to W/W1, and W2. This keeps furnace locked in
high-heat operation. Repeat items d through g for high-heat
operation.
h. Remove jumpers R to W/W1 and R to W2.
CAUTION
!
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in shorten furnace life.
Set air temperature rise within limits specified on the rating plate to
prevent reduced life of furnace components.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in overheating the heat
exchangers or condensing flue gases in heat exchanger areas not
designed for condensate.
Temperature rise must be within limits specified on unit rating plate.
Table 18 – Gas Rate (CU ft./hr.)
SIZE OF TEST DIAL
SEC.
FOR 1
1 Cu
2 Cu
5 Cu
REV.
Ft.
Ft.
10
360
720
1800
11
327
655
1636
12
300
600
1500
13
277
555
1385
14
257
514
1286
(Tabulated Data Based on 22,000 BTUh High-Heat/14,500 BTUh for Low-Heat per Burner, Derated 4 Percent for
AVG. GAS HEAT
ALTITUDE RANGE FT.
VALUE (BTUH/CU
(M)
0 to
USA
2000
(0 to 610)
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
SIZE OF TEST DIAL
SEC. FOR
1 Cu
2 Cu
Ft.
1 REV.
Ft.
Ft.
50
72
144
51
71
141
52
69
138
53
68
136
54
67
133
Table 19 – Orifice Size and Manifold Pressure (in. w.c.) for Gas Input Rate
Each 1000 Ft. (305 M) Above Sea Level)
0.58
Manifold
Pressure
FT.)
Orifice No.
High/Low
900
42
3.5/1.5
925
42
3.3/1.4
950
43
3.8/1.7
975
43
3.6/1.6
1000
43
3.5/1.5
1025
43
3.3/1.4
1050
44
3.6/1.6
1075
44
3.4/1.5
1100
44
3.3/1.4
Table 18 – Gas Rate (CU ft./hr.) (Continued)
SIZE OF TEST DIAL
SEC.
FOR 1
1 Cu
REV.
Ft.
15
240
16
225
17
212
18
200
19
189
20
180
21
171
22
164
23
157
24
150
25
144
26
138
27
133
28
129
29
124
30
120
31
116
32
113
33
109
34
106
35
103
36
100
37
97
38
95
39
92
40
90
41
88
42
86
43
84
44
82
45
80
46
78
5 Cu
47
76
Ft.
48
75
360
49
73
355
346
340
333
SPECIFIC GRAVITY OF NATURAL GAS
0.60
Manifold
Pressure
Orifice No.
High/Low
42
3.6/1.6
42
3.4/1.5
42
3.3/1.4
43
3.8/1.6
43
3.6/1.6
43
3.4/1.5
43
3.2/1.4
44
3.5/1.5
44
3.4/1.5
34
SIZE OF TEST DIAL
2 Cu
5 Cu
SEC. FOR
1 Cu
Ft.
Ft.
1 REV.
480
1200
55
450
1125
56
424
1059
57
400
1000
58
379
947
59
360
900
60
343
857
62
327
818
64
313
783
66
300
750
68
288
720
70
277
692
72
267
667
74
257
643
76
248
621
78
240
600
80
232
581
82
225
563
84
218
545
86
212
529
88
206
514
90
200
500
92
195
486
94
189
474
96
185
462
98
180
450
100
176
439
102
172
429
104
167
419
106
164
409
108
160
400
110
157
391
112
153
383
116
150
375
120
147
367
0.62
Manifold
Pressure
Orifice No.
High/Low
Orifice No.
42
3.7/1.6
42
3.5/1.5
42
3.4/1.5
42
3.2/1.4
43
3.7/1.6
43
3.5/1.5
43
3.4/1.5
43
3.2/1.4
44
3.5/1.5
2 Cu
5 Cu
Ft.
Ft.
Ft.
65
131
327
64
129
321
63
126
316
62
124
310
61
122
305
60
120
300
58
116
290
56
112
281
54
109
273
53
106
265
51
103
257
50
100
250
48
97
243
47
95
237
46
92
231
45
90
225
44
88
220
43
86
214
42
84
209
41
82
205
40
80
200
39
78
196
38
76
192
38
75
188
37
74
184
36
72
180
35
71
178
35
69
173
34
68
170
33
67
167
33
65
164
32
64
161
31
62
155
30
60
150
0.64
Manifold
Pressure
High/Low
41
3.5/1.5
42
3.7/1.6
42
3.5/1.5
42
3.3/1.4
43
3.8/1.7
43
3.6/1.6
43
3.5/1.5
43
3.3/1.4
43
3.2/1.4
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