A.O. Smith 404 - Manual (Page 15)

15
DIRECT 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. 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.
TABLE 13. DIRECT VENT (HORIZONTAL EXHAUST CONFIGURATIONS)
Figure 9.
APPLIANCE CERTIFIED EXHAUST MAXIMUM AIR INTAKE AIR INTAKE MAXIMUM
MODEL CATEGORY EXHAUST VENT VENT SIZE EXHAUST VENT MATERIAL SIZE AIR INTAKE
MATERIAL INCHES (cm) LENGTH FT (m) INCHES (m) LENGTH FT (m)
GAL. STEEL
III PVC, ABS OR
CPVC
GAL.STEEL
III PVC, ABS CR
CPVC
GAL. STEEL
III PVC, ABS OR
CPVC
GAL. STEEL
III PVC, ABS OR
CPVC
GAL. STEEL
III PVC, ABS OR
CPVC
I000
1300
1500
1850
2100
2500
STAINLESS
(SEALED)
STAINLESS
(SEALED)
STAINLESS
(SEALED)
STAINLESS
(SEALED)
STAINLESS
(SEALED)
10"
(25.4 cm)
12"
(30.5 cm)
14"
(35.6 cm)
14"
(35.6 cm)
16"
(40.6 cm)
35'
(10.7 m)
35'
(10.7 m)
20'
(6.1 m)
20'
(6.1 m)
20'
(6.1 m)
35'
(10.7 m)
35'
(10.7 m)
20'
(6.1 m)
20'
(6.1 m)
20'
(6.1 m)
8"
(20.3 cm)
10"
(25.4 cm)
10"
(25.4 cm)
12"
(30.5 cm)
12"
(30.5 cm)