Field Installation Of Draft Hoods; Tools And Materials; Types Of Draft Hoods Covered In This Section - A.O. Smith GCV300 Service Handbook

air openings). See "Pilot Outage:
Insufficient Makeup Air" and "Pilot
Outage: Decompression" for more
information (pp. 24
respectively). In the short term,
however, open a hot water faucet and
allow the water to flow until it reaches
a safe temperature.
26 • Residential Standard Gas Water Heater Service Handbook
FIELD
INSTALLATION OF
DRAFT HOODS
& 25,
The purpose of this section is to show
how to properly connect draft hoods
to single- and double-wall (Type B)
vent pipe. These instructions cover
3-inch, 4-inch, and combination draft
hood sizes.
A draft hood is critical to the operation
of a gas water heater. (It is attached
between the heater's flue outlet
and the vent pipe.) When properly
installed, the draft hood cools the
combustion products and allows them
to flow safely from the building. It
also protects heater operation during
updrafts and downdrafts that are
caused by indoor/outdoor air pressure
differences.
WARNING!
• The venting system shall comply
with applicable local and state/
provincial codes. The venting system
shall also comply with the current
edition of the National Fuel Gas
Code ANSI Z223.1/NFPA 54 (U.S.A.)
or the Natural Gas and Propane
Installation Code CAN/CSA-B149.1
(Canada).
• Each standard vent gas water heater
is supplied with a specific draft
hood. This ensures the safe, correct
operation of the water heater.
However, the draft hood must be
installed correctly.
• Do not use a draft hood other than
the one that is supplied with the
water heater.
• Do not re-use any previously
installed draft hood.
used parts should be discarded.
• Do not modify, cut, or bend a draft
hood during installation.
• Do not block or restrict the open
areas around the draft hood. Do not
2 Originally published as 187010-000.
store or place objects on top of the
water heater.
• Install the draft hood securely to the
2
water heater and flue pipe according
to the installation instructions.
These instructions were provided
with the water heater.
• Do not use flex vent pipe or dryer
vent pipe.
• Vent pipe should be made of
galvanized steel.
aluminum vent pipe.
• Always wear work gloves when
working with sheet metal parts.

Tools and Materials

The following tools and materials
may be required to install the draft
hood and vent pipe. Other tools and
materials may be needed.
• Work Gloves
• Flat-ended pliers
• Water Heater Installation Manual
• 1/4-inch hex nut driver
• Screw driver with flat tip
• Powered screw driver tool (optional)
• Tape measure (for checking sizes)
• Sheet metal cutting tools (optional)
Types of Dra Hoods Covered in
this Sec on
Previously
Combination Draft Hood (3-in./4-in.)
Do not use
3-inch Draft Hood
4-inch Draft Hood
Figure 29.