A.O. Smith 404 - Manual (Page 14)

14
DIRECT VENT - VERTICAL (CATEGORY I)
TABLE 12. DIRECT VENT (VERTICAL EXHAUST CONFIGURATIONS)
• Connection for the appliance exhaust vent to the stack must be as direct as possible. Maximum and minimum venting length
for Category I appliances shall be determined per the latest edition of the National Fuel Code (U.S.) and CAN/CSA-B149.1
Installation Code (Canada).
• The vent should be installed so as to prevent the accumulation of condensate and, where necessary, have means provided for
drainage of condensate. The horizontal breaching of a vent must have an upward slope of not less than 1/4 inch per linear foot
(2 cm/m) from the boiler to the vent terminal. The horizontal portion of the vent shall be supported to maintain clearances and to
prevent physical damage or separation of joints.
Figure 8.
APPLIANCE CERTIFIED EXHAUST VENT MAXIMUM AIR INTAKE AIR INTAKE MAXIMUM
MODEL CATEGORY EXHAUST VENT SIZE EXHAUST VENT MATERIAL SIZE AIR INTAKE
MATERIAL INCHES (cm) LENGTH FT (m) INCHES (cm) LENGTH FT (m)
GAL. STEEL
I PVC, ABS OR
CPVC
GAL.STEEL
I PVC, ABS CR
CPVC
GAL. STEEL
I PVC, ABS OR
CPVC
GAL. STEEL
I PVC, ABS OR
CPVC
GAL. STEEL
I PVC, ABS OR
CPVC
I000
1300
1500
1850
2100
2500
TYPE B OR
EQUIVALENT
TYPE B OR
EQUIVALENT
TYPE B OR
EQUIVALENT
TYPE B OR
EQUIVALENT
TYPE B OR
EQUIVALENT
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)