19 − In no case, shall the vent connector be sized more than two consecutive table size diameters over the size of the draft hood outlet or flue collar outlet.
20 − Do not install a manual damper, barometric draft regu- lator or flue restrictor between the furnace and the chimney.
21 − When connecting this appliance to an existing dedi-
TABLE 5
Capacity of Type B Double−Wall Vents with Type B Double−Wall Connectors
Serving a Single Category I Appliance
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| Vent and Connector Diameter − D (inches) |
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Height | Lateral |
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| 3 Inch |
| 4 Inch |
| 5 Inch |
| 6 Inch | ||||||
H | L |
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| Appliance Input Rating in Thousands of Btu Per Hour |
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(feet) | (feet) |
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| MIN |
| MAX | MIN |
| MAX | MIN |
| MAX | MIN |
| MAX |
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| 0 | 0 |
| 78 | 0 |
| 152 | 0 |
| 251 | 0 |
| 375 |
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| 2 | 13 |
| 51 | 18 |
| 97 | 27 |
| 157 | 32 |
| 232 |
6 |
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4 | 21 |
| 49 | 30 |
| 94 | 39 |
| 153 | 50 |
| 227 | |
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| 6 | 25 |
| 46 | 36 |
| 91 | 47 |
| 149 | 59 |
| 223 |
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| 0 | 0 |
| 84 | 0 |
| 165 | 0 |
| 276 | 0 |
| 415 |
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| 2 | 12 |
| 57 | 16 |
| 109 | 25 |
| 178 | 28 |
| 263 |
8 |
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5 | 23 |
| 53 | 32 |
| 103 | 42 |
| 171 | 53 |
| 255 | |
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| 8 | 28 |
| 49 | 39 |
| 98 | 51 |
| 164 | 64 |
| 247 |
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| 0 | 0 |
| 88 | 0 |
| 175 | 0 |
| 295 | 0 |
| 447 |
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| 2 | 12 |
| 61 | 17 |
| 118 | 23 |
| 194 | 26 |
| 289 |
10 |
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5 | 23 |
| 57 | 32 |
| 113 | 41 |
| 187 | 52 |
| 280 | |
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| 10 | 30 |
| 51 | 41 |
| 104 | 54 |
| 176 | 67 |
| 267 |
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| 0 | 0 |
| 94 | 0 |
| 191 | 0 |
| 327 | 0 |
| 502 |
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| 2 | 11 |
| 69 | 15 |
| 136 | 20 |
| 226 | 22 |
| 339 |
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15 | 5 | 22 |
| 65 | 30 |
| 130 | 39 |
| 219 | 49 |
| 330 |
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| 10 | 29 |
| 59 | 40 |
| 121 | 51 |
| 206 | 64 |
| 315 |
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| 15 | 35 |
| 53 | 48 |
| 112 | 61 |
| 195 | 76 |
| 301 |
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| 0 | 0 |
| 97 | 0 |
| 202 | 0 |
| 349 | 0 |
| 540 |
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| 2 | 10 |
| 75 | 14 |
| 149 | 18 |
| 250 | 20 |
| 377 |
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| 5 | 21 |
| 71 | 29 |
| 143 | 38 |
| 242 | 47 |
| 367 |
20 |
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10 | 28 |
| 64 | 38 |
| 133 | 50 |
| 229 | 62 |
| 351 | |
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| 15 | 34 |
| 58 | 46 |
| 124 | 59 |
| 217 | 73 |
| 337 |
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| 20 | 48 |
| 52 | 55 |
| 116 | 69 |
| 206 | 84 |
| 322 |
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| 0 | 0 |
| 100 | 0 |
| 213 | 0 |
| 374 | 0 |
| 587 |
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| 2 | 9 |
| 81 | 13 |
| 166 | 14 |
| 283 | 18 |
| 432 |
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| 5 | 21 |
| 77 | 28 |
| 160 | 36 |
| 275 | 45 |
| 421 |
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30 | 10 | 27 |
| 70 | 37 |
| 150 | 48 |
| 262 | 59 |
| 405 |
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| 15 | 33 |
| 64 | 44 |
| 141 | 57 |
| 249 | 70 |
| 389 |
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| 20 | 56 |
| 58 | 53 |
| 132 | 66 |
| 237 | 80 |
| 374 |
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| 30 | NA |
| NA | 73 |
| 113 | 88 |
| 214 | 104 |
| 346 |
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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).
Page 14