Page 5
TABLE 4
Multiple Appliance for Interior and Exterior Masonry Chimney
Type B Double Wall Vent Connectors Serving a Single Furnace
with Masonry Chimney Vent Adapter Kit and One or More Drafthood−Equipped Appliances
Vent
Height
H
(ft)
Connector
Rise
R
(ft)
Type B Double Wall Connector Diameter − (inches)
6 in.
7 in.
8 in.
Appliance Input Rate in Thousands of Btu per Hour
NAT
Max
NAT
Max
NAT
Max
6
1
2
3
101
124
143
141
173
203
201
232
270
8
1
2
3
105
127
145
148
179
206
210
240
276
10
1
2
3
108
129
148
153
184
209
216
247
281
15
1
2
3
114
134
153
164
192
215
229
260
292
20
1
2
3
119
138
157
173
199
222
239
270
301
30
1
2
3
127
145
163
187
209
233
255
287
317
35
1
2
3
131
149
167
194
216
240
265
297
332
TABLE 5
Multiple Appliance for Interior and Exterior Masonry Chimney
MASONRY CHIMNEY INTERNAL AREA
Height
H
(ft)
Minimum Internal Area of Chimney (Square Inches)
38
50
63
Combined Appliance Input Rating in Thousands of Btu Per Hour
NAT
+NAT
NAT
+NAT
NAT
+NAT
6
103
143
188
8
119
163
218
10
131
177
236
15
152
212
283
20
172
243
325
30
198
278
381
35
NR
291
401
NR − Not recommended for vent configuration.
