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Never obstruct the flow of ventilation air. If you have any doubts
or questions at all, call your gas supplier. Failure to provide the
proper amount of combustion air can result in a fire or explosion
and cause property damage, serious bodily injury or death.
unconfined space
An Unconfined Space is one whose volume IS NOT LESS THAN
50 cubic feet per 1,000 Btu/hr (4.8 cubic meters per kW) of the
total input rating of all appliances installed in the space. Rooms
communicating directly with the space, in which the appliances
are installed, through openings not furnished with doors, are
considered a part of the unconfined space.
Makeup air requirements for the operation of exhaust fans,
kitchen ventilation systems, clothes dryers and fireplaces shall
also be considered in determining the adequacy of a space to
provide combustion, ventilation and dilution air.
unusually tight construction
In unconfined spaces in buildings, infiltration may be adequate
to provide air for combustion, ventilation and dilution of flue
gases. However, in buildings of unusually tight construction (for
example, weather stripping, heavily insulated, caulked, vapor
barrier, etc.) additional air must be provided using the methods
described in the Confined Space section that follows.
confined space
A Confined Space is one whose volume IS LESS THAN 50 cubic
feet per 1,000 Btu/hr (4.8 cubic meters per kW) of the total input
rating of all appliances installed in the space.
Openings must be installed to provide fresh air for combustion,
ventilation and dilution in confined spaces. The required size for
the openings is dependent on the method used to provide fresh
air to the confined space AND the total Btu/hr input rating of all
appliances installed in the space.
exhaust fans
Where exhaust fans are installed, additional air shall be provided
to replace the exhausted air. When an exhaust fan is installed
in the same space with a water heater, sufficient openings to
provide fresh air must be provided that accommodate the
requirements for all appliances in the room and the exhaust fan.
Undersized openings will cause air to be drawn into the room
Venting
ThE INsTRUCTIoNs IN ThIs sECTIoN oN VENTING MUsT
BE FoLLoWED To AVoID ChokED CoMBUsTIoN oR
RECIRCULATION OF FLUE GASES. SUCH CONDITIONS
CAUSE SOOTING OR RISKS OF FIRE AND ASPHYXIATION.
Heater must be protected from freezing downdrafts.
Remove all soot or other obstructions from the chimney that will
retard a free draft.
Type B venting is recommended with these heaters. For
typical venting application see TECHNICAL DATA VENTING
on page 18.
This water heater must be vented in compliance with all local
codes, the current revision of the National Fuel Gas Code
(ANSI-Z223.1) and with the Category I Venting Tables.
If any part of the vent system is exposed to ambient temperatures
below 40°F it must be insulated to prevent condensation.
through the water heater's vent system causing poor combustion.
Sooting, serious damage to the water heater and the risk of fire
or explosion may result. It can also create a risk of asphyxiation.
louVers and grilles
The free areas of the fresh air openings in the instructions that
follow do not take in to account the presence of louvers, grilles
or screens in the openings.
The required size of openings for combustion, ventilation
and dilution air shall be based on the "net free area" of each
opening. Where the free area through a design of louver or
grille or screen is known, it shall be used in calculating the
size of opening required to provide the free area specified.
Where the louver and grille design and free area are not
known, it shall be assumed that wood louvers will have 25%
free area and metal louvers and grilles will have 75% free
area. Non motorized louvers and grilles shall be fixed in the
open position.
Vent adapter
The SBD85500NE/SBD85500PE model is shipped with a 6" to
8" diameter vent adapter (Fig. 11). The vent adapter fits on top
of the installed blower exhaust. Use only vent adapters supplied
with the unit. The venting must comply with the NATIONAL
FUEL GAS CODE, ANSI Z223.1/NFPA 54 and for Canadian
installations consult the Canadian Installation Code CAN/CSA
B149.1-00.
Venting installation
• Do not connect the heater to a common vent or chimney
• Where a separate vent connection is not available and the
15
figure 11
with solid fuel burning equipment. This practice is
prohibited by many local
practice of venting gas fired equipment to the duct work
of ventilation systems.
figure 12
vent pipe from the heater must be connected to a common
building codes as is the
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