Lennox MERIT ML180UHE Installation Instructions Manual page 19

Capacity of Type B Double−Wall Vents with Single−Wall Metal Connectors
Height Lateral
H L
(feet) (feet)
0
2
6
4
6
0
2
8
5
8
0
2
10
5
10
0
2
5
15
10
15
0
2
5
20
10
15
20
0
2
5
10
30
15
20
30
NOTE − Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other
vent configurations, the vent system is assumed to have two 90° elbows. For each additional 90° elbow or equivalent (for example two 45°
elbows equal one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.90 x maxi-
mum listed capacity).
Serving a Single Category I Appliance
3 Inch
Appliance Input Rating in Thousands of Btu Per Hour
MIN MAX MIN
38 77 59
39 51 60
NA NA 74
NA NA 83
37 83 58
39 56 59
NA NA 77
NA NA 90
37 87 57
39 61 59
52 56 76
NA NA 97
36 93 56
38 69 57
51 63 75
NA NA 95
NA NA NA
35 96 54
37 74 56
50 68 73
NA NA 93
NA NA NA
NA NA NA
34 99 53
37 80 55
49 74 72
NA NA 91
NA NA 115
NA NA NA
NA NA NA
TABLE 4
Vent and Connector Diameter − D (inches)
4 Inch
MAX MIN
151 85
96 85
92 102
89 114
164 83
108 83
102 107
95 122
174 82
117 82
111 105
100 132
190 80
136 80
128 102
116 128
NA 158
200 78
148 78
140 100
129 125
NA 155
NA 186
211 76
164 76
157 98
144 122
131 151
NA 181
NA NA
Page 19
5 Inch 6 Inch
MAX MIN
249 126
156 123
152 146
147 163
273 123
176 121
168 151
161 175
293 120
193 119
185 148
171 188
325 116
225 115
216 144
201 182
186 220
346 114
248 113
239 141
223 177
208 216
192 254
372 110
281 109
271 136
255 171
239 208
223 246
NA NA
MAX
373
231
225
220
412
261
252
243
444
287
277
261
499
337
326
308
290
537
375
363
344
325
306
584
429
417
397
377
357
NA