A.O. Smith ATX-199 Instruction Manual page 21

Figure 10. Vertical Duct Openings
1 in
per 2,000 btu/h
Space
1 in 2 (6.5 cm
per 2,000 btu/h
Figure 11.
Figure 12. Outdoor Air Through One Opening
Outlet air to
2 2 )
per 4,000 btu/h
2 2 )
per 4,000 btu/h
2 2
(6.5 cm )
Outlet
Air Ducts
Inlet
2 )
1 in 2 (6.5 cm 2 )
12" (305 mm)
maximum
Space
Figure 13. Indoor Air Through Two Permanent Openings
MAXIMUM EQUIVALENT PIPE LENGTHS AND ELBOWS
Table 7.
Table 7. Equivalent Lengths and Maximum Number of Elbows
3" (76 mm) Venting
No. of
Elbows
0 to 3,000 ft 3,001 to 6,000 ft
(0 to 914 m) (915 to 1,829 m)
0
1
2
3
4
5
Max. No. of
Diameter
Elbows
5
4 in. (102
5
21
2
1 in per
Two permanent
1,000 btu/h
Openings
12 (305 mm) maximum
4" (102 mm)
Venting
6,001 to 10,100 ft 0 to 10,100 ft
(1,830 to 3,078 m) (0 to 3,078 m)
(Total) Vent Length