A.O. Smith 404 User Manual
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TABLE 11. STANDARD HORIZONTAL VENTING (CATEGORY III)
STANDARD VENT - HORIZONTAL (CATEGORY III)
WARNING: No substitutions of flue pipe or vent cap material are allowed. Such substitutions would jeopardize the
safety and health of inhabitants.
• A maximum of two elbows can be used on inlet and outlet vent piping respectively. Each elbow is equal to 10 feet (3 m) of
straight pipe.
• Use only special gas vent pipes listed for use with Category III gas burning heaters, such as stainless steel Saf-T-Vent
by Heat Fab, Inc., available from A.O. Smith, 500 Tennessee Waltz Parkway, Ashland City, TN 37015 Phone: 1-800-433-2545
or Fax: 1-800-433-2515. Pipe joints must be positively sealed.
Figure 7.
APPLIANCE
CERTIFIED
EXHAUST
MAXIMUM
MODEL
CATEGORY
VENTING
VENT SIZE
VENT LENGTH
MATERIAL
INCHES (cm)
FEET (m)
STAINLESS
STEEL
1300
STAINLESS
1500
STEEL
1850
STAINLESS
2100
STEEL
STAINLESS
STEEL
III
III
III
III
I000
2500
10”(25.4 cm)
12" (30.5 cm)
14"(35.6 cm)
16" (40.6 cm)
70' (21.3 m)
70' (21.3 m)
35' (10.7 m)
35' (10.7 m)