John Wood Atmospheric Gas (ENERGY STAR) - NEW - Manuel (Page 12)

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The size of openings is determined by the method in which the
air is to be provided. For specific ventilation and combustion air
requirements, consult the Natural Gas and Propane Installation
Code (CAN/CSA B149.1-current edition) and the local codes of
your area.
Louvers and Grilles
In calculating free area for ventilation and combustion
air supply openings, consideration must be given to the
blocking effect of protection louvers, grilles, and screens.
These devices can reduce airflow, which in turn may
require larger openings to achieve the required minimum
free area. Screens must not be smaller than 1/4” mesh
(6.35 mm). If the free area through a particular design of
louver or grille is known, it should be used in calculating
the specified free area of the opening. If the design and
free area are not known, it can be assumed that most
wood louvers will allow 20 - 25% of free area while metal
louvers and grilles will allow 60 - 75% of free area.
Louvers and grilles must be interconnected with the
equipment so that they are opened automatically during
equipment operation. Also, keep louvers and grilles clean
and free of debris or other obstructions. Do not use
manually adjustable louvers.
Consult the local codes of your area for specific ventilation
and combustion air requirements.
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 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 CAN/
CSA B149.1-current edition (Natural Gas and Propane
Installation Code) and all local/provincial codes.
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.
• Certified (listed) 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.
• The venting system must be installed by a qualified
technician
Draft Hood Installation
Draft hood
Flue Damper
Draft hood
Leg Tips*
* Twist or bend the leg tips to secure the draft hood to the flue damper
FIGURE 9.
Align the legs of the draft hood with the slots provided.
Insert the draft hood leg tips into slots on the flue damper’s
flange as shown in Figure 9. Secure the draft hood by
twisting or bending the leg tips. See Figure 9. Do not alter
the draft hood in any way. If you are replacing an existing
water heater, be sure to use the new draft hood supplied
with the water heater.
Vent Pipe Size
It is important that you follow the guidelines in these
instructions for sizing a vent pipe system. If a transition
to a larger vent size is required, the vent transition
connection must be made at the draft hood outlet.
Vent Connectors
1. Type B, Double wall, U.L. Listed Vent Pipe.
2. Single wall Vent Pipe.
Maintain the manufacturer’s specified minimum clearance
from combustible materials when using type B double wall
vent pipe.
Vent connectors made of type B, double wall vent pipe
material may pass through walls or partitions constructed
of combustible material if the minimum listed clearance is
maintained.
Maintain a twelve inch (300 mm) minimum clearance from
all combustible materials when using single wall vent pipe.
IMPORTANT: Single wall vent pipe cannot be used for
water heaters located in attics and may not pass through
attic spaces, crawl spaces or any confined or inaccessible
location. A single wall metal vent connector cannot pass
through any interior wall.
When installing a vent connector, please note the following
(See Figures 10-12):
•
Install the vent connector avoiding unnecessary bends,
which create resistance to the flow of vent gases.
• Install without dips or sags with an upward slope of at
least 1/4-inch per foot (21 mm per metre).
• Joints must be fastened by sheet metal screws or other
approved means. It must be supported to maintain
clearances and prevent separation of joints and dam-
age.
• The length of the vent connector cannot exceed 75% of
the vertical vent height.
• The vent connector must be accessible for cleaning,
inspection, and replacement.