Whirlpool WFCU Installation Instructions Manual page 9

Vent Pipe Size and Length
The vent pipe and air intake pipe (in direct vent installations) should be sized in accordance with the information found in the Vent Table
charts. One 90° elbow is equivalent to 5 ft (1.5 m) of pipe. Two 45° elbows are equivalent to one 90° elbow. The minimum length
certified for use with this furnace is 5 ft (1.5 m) and one elbow, not including the vent and air intake terminals.
Vent Table—40,000 to 80,000 Btu/h Models
Vent Pipe Length—ft (m) Minimum Pipe Diameter—in. (cm)
5 (1.5)
10 (3)
20 (6.1)
30 (9.1)
40 (12.2)
50 (15.2)
60 (18.3)
70 (21.3)
80 (24.4)
90 (27.4)
Number of 90º Elbows
NR = Not Recommended
Vent Table—90,000 to 100,000 Btu/h Models
Vent Pipe Length—ft (m) Minimum Pipe Diameter—in. (cm)
5 (1.5)
10 (3)
20 (6.1)
30 (9.1)
40 (12.2)
50 (15.2)
60 (18.3)
70 (21.3)
80 (24.4)
90 (27.4)
Number of 90° Elbows
NR = Not Recommended
1¹⁄₂ (3.8) 1¹⁄₂ (3.8) 2 (5.1)
1¹⁄₂ (3.8) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2¹⁄₂ (6.4)
2 (5.1) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 3 (7.6)
0 1 2
NR 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2¹⁄₂ (6.4)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4)
2¹⁄₂ (6.4) 3 (7.6) 3 (7.6)
3 (7.6) 3 (7.6) 3 (7.6)
3 (7.6) 3 (7.6) 3 (7.6)
3 (7.6) 3 (7.6) NR
0 1 2
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 3 (7.6)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 3 (7.6)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 3 (7.6)
3 (7.6) 3 (7.6) 3 (7.6)
3 (7.6) 3 (7.6) 3 (7.6)
3 4 5
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 3 (7.6)
3 (7.6) 3 (7.6) 3 (7.6)
3 (7.6) 3 (7.6) 3 (7.6)
3 (7.6) 3 (7.6) NR
NR NR NR
NR NR NR
3 4 5
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2 (5.1) 2 (5.1)
2 (5.1) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4)
3 (7.6)
3 (7.6) 3 (7.6) 3 (7.6)
3 (7.6) 3 (7.6) NR
3 (7.6) NR NR
6 7 8
2 (5.1) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 2¹⁄₂ (6.4)
2¹⁄₂ (6.4) 2¹⁄₂ (6.4) 3" (7.6)
3 (7.6) 3 (7.6)
3 (7.6) 3 (7.6) 3 (7.6)
3 (7.6) 3 (7.6) 3 (7.6)
3 (7.6) NR NR
NR NR NR
NR NR NR
NR NR NR
6 7 8
2 (5.1)
2 (5.1)
2¹⁄₂ (6.4)
3 (7.6)
NR
NR
NR
9
3 (7.6)
3 (7.6)
NR
NR
NR
NR
NR
9
9