A.O. Smith 315456-002 User Manual

FIGURE 8B.

Vent Pipe System

This water heater uses a non-direct, single-pipe vent

system to remove exhaust gases created by the burning of

fossil fuels. Air for combustion is taken from the immediate

water heater location or is ducted in from the outside (see

“Combustion Air Supply and Ventilation”).
This water heater must be properly vented for the removal

of exhaust gases to the outside atmosphere. Correct

installation of the vent pipe system is mandatory for the

proper and efficient operation of this water heater and is

an important factor in the life of the unit.
The vent pipe must be installed according to all local and

state codes or, in the absence of local and state codes, the

“National Fuel Gas Code”, ANSI Z223.1(NFPA 54)-current

edition. The vent pipe installation must not be obstructed

so as to prevent the removal of exhaust gases to the

outside atmosphere.
IMPORTANT: The use of vent dampers is not

recommended by the manufacturer of this water heater.

Although some vent dampers are certified by CSA

International, this certification applies to the vent damper

device only and does not mean they are certified for use

on this water heater.
U.L. recognized fuel gas and carbon monoxide (CO)

detectors are recommended in all applications and should

be installed using the manufacturer’s instructions and local

codes, rules, or regulations.
IMPORTANT: If you lack the necessary skills required

to properly install this venting system, you should not

proceed, but get help from a qualified technician.

Draft Hood Installation

Sheet Metal Screws (Four Provided)

Draft Hood

Legs

Slot

Jacket Top

Install The Draft Hood With The Four Screws Provided.

FIGURE 9

FIGURE 6.

FIGURE 7.

FIGURE 8A.

All Air From Outdoors: Inlet Air From Ventilated

Crawl Space/Outlet Air To Ventilated Attic

Confined

Space

Outlet Air

to the Attic

1 sq. in. per

4000 BTUH

Inlet Air

from the

Crawl Space

Alternative

Air Inlet

1 sq. in. per

4000 BTUH

Open

Foundation

Vent

Gable Vent

to Outdoor

Install Above

Insulation

Gable Vent

to Outdoors

Install Above

Insulation

Confined

Space

All Air from Outdoors Through Ventilated Attic

Outlet Air

to the Attic

1 sq. in. per

4000 BTUH

Inlet Air Duct

1 sq. in. per

4000 BTUH

12” Max.

All Air From Outdoors Using Horizontal Ducts

Confined

Space

Outlet

Outdoor

Air Ducts

Inlet

1 sq. in. per

2000 BTUH

1 sq. in. per

2000 BTUH

All Air From Outdoors - Using A Single Permanent Opening

Confined

Space

1 sq. in. per

3000 BTUH

Alternative
Opening
Location