Residential Standard Gas Water Heater Service Handbook • 27
SUPPLEMENTS
Types of Vent Pipe Covered in
this Sec
Ɵ
on
• Single Wall - Galvanized Steel
• Double Wall (Type B) - Galvanized
Steel
Installa
Ɵ
on Procedure
1. Determine the size of the draft
hood.
To determine the size of a draft hood,
measure across the portion that will fit
into the vent or vent connector. (Vent
connection will be covered later.)
Example:
Figure 30.
3”
4”
DĞĂƐƵƌŝŶŐĂŽŵďŝŶĂƟŽŶ
ƌĂŌ,ŽŽĚ
2. Install the draft hood to the water
heater according to the installation
manual.
NOTE:
There are two methods for
securing a draft hood. Use only the
method that applies to your water
heater model.
•
Lock-in Type:
Some draft hoods
have notches at the bottom of
each leg. Simply align the legs
of the draft hood with the slots
in the top of the water heater.
Insert the legs, then rotate the
draft hood. Ensure that the
draft hood is secure before you
proceed.
•
Push-in Type with screws:
Most
draft hoods are designed to be
secured with screws (which are
provided). Align the legs of the
draft hood with the slots in the
top of the water heater. Insert
the legs into the slots, then
secure them with screws as
described in your installation
manual.
3. Connect the draft hood to the
venting system as described below.
IMPORTANT:
The inside diameter
of the vent pipe or draft hood
connector may vary slightly by
manufacturer. Always verify that
vent connections are secure and air
tight.
In instances where correctly-
matched pieces will not fit together,
use flat-ended pliers to flare the
end of the pipe or flatten its seam
joint. However, do not modify, cut,
or bend the draft hood.
Figure 31.
Figure 32.
A. Fit the female end of the vent
pipe over the draft hood as
shown below. Note that you may
need to adjust or reposition the
vent pipe during this process.
If you are connecting the draft
hood to Type B vent pipe or to
vent pipe of a different size or
brand, read the Coupling section
before you proceed.
Vent Pipe
ƌĂŌ,ŽŽĚ
Figure 33.
B. Verify that all vent connections
are secure and air tight.
C. Secure the vent pipe to the draft
hood with self-drilling screws.
Also secure any new sections of
vent pipe.
Use a minimum of three screws
per connection. Screws should
be evenly spaced. For example,
three screws should be spaced at
120 degree increments around
the perimeter of the vent pipe.
IMPORTANT:
Only use screws
that are 5/8” long or less in
length.
Coupling
The opening of your draft hood will be
either 3-inches or 4-inches in diameter.
(You measured the diameter during
Step 1 of the
Installation Procedure
section.)
• If you are connecting double wall
(Type B) vent pipe to the draft hood,
you must use a Type B draft hood
connector. Without this connector,
double wall vent pipe will not fit the
draft hood properly. See
Type B Draft
Hood Connectors
.
• Compare the size of your draft hood
opening to the size of the vent pipe.
If the vent pipe has a wider diameter
than the draft hood, use an adapter
to connect them. See Figure 34 on
page 28.
To
Ň
are the end of the vent
pipe, bend the edge outward
all the way around the
perimeter (approx.
1/4-inch from the
edge).
If necessary, use
Ň
at-ended pliers
to
Ň
are the end
of the pipe or to
ŇĂƩĞ
n the seam
joint.
Seam Joint
End View of Vent Pipe
