Insulation Blankets; Air Requirements; Unconfi Ned Space; Unusually Tight Construction - A.O. Smith RESIDENTIAL GAS WATER HEATERS Installation And Operating Manual

If this water heater will be used in beauty shops, barber
shops, cleaning establishments, or self-service laundries
with dry cleaning equipment, it is imperative that the water
heater or water heaters be installed so that combustion
and ventilation air be taken from outside these areas.
Propellants of aerosol sprays and volatile compounds,
(cleaners, chlorine based chemicals, refrigerants, etc.) in
addition to being highly fl ammable in many cases, will also
react to form corrosive hydrochloric acid when exposed to
the combustion products of the water heater. The results
can be hazardous, and also cause product failure.

INSULATION BLANKETS

Insulation blankets are available to the general public for
external use on gas water heaters but are not necessary
with these products. The purpose of an insulation blanket
is to reduce standby heat loss encountered with storage
tank heaters. Your water heater meets or exceeds
the current standards with respect to insulation and
standby loss requirements, making an insulation blanket
unnecessary.
Should you choose to apply an insulation blanket to
this heater, you should follow these instructions (For
identifi cation of components mentioned below, see Figures
1-7). Failure to follow these instructions will restrict the air
fl ow required for proper combustion and dilution, potentially
resulting in fi re, asphyxiation, serious personal injury or
death.
•
Do not apply insulation to the top of the water heater,
as this will interfere with safe operation of the blower
assembly.
•
Do not cover the outer door, thermostat or T&P relief
valve, FV sensor, or Air Intake Snorkel.
•
Do not cover the "Installation And Operating manual".
Keep it on the side of the water heater or nearby for
future reference.
•
Do obtain new warning and instruction labels from the
manufacturer for placement on the blanket directly over
the existing labels.
•
Do inspect the insulation blanket frequently to make
certain it does not sag, thereby obstructing combustion
air fl ow.
WARNING
Breathing Hazard - Carbon Monoxide Gas
• Do not obstruct water heater air intake(s) with
insulating jacket.
• Gas and carbcn monoxide detectors are available.
• Install water heater in accordance with the
instruction manual and NFPA54.
Breathing carbon monoxide can cause brain damage or death.
Always read and understand instruction manual.

AIR REQUIREMENTS

For safe operation an adequate supply of fresh,
uncontaminated air for combustion dilution and ventilation
must be provided.
Note: Contaminated or dusty air may cause build-up on
the blower wheel resulting in nuisance shut downs.
An insuffi cient supply of air can cause recirculation of
combustion products resulting in contamination that may
be hazardous to life. Such a condition often will result in
a yellow, luminous burner fl ame, causing sooting of the
combustion chamber, burners and fl ue tubes and creates
a risk of asphyxiation.
Do not install the water heater in a confi ned space unless
an adequate supply of air for combustion dilution and
ventilation is brought into that space using the methods
described in the "Confi ned Space" section that follows.
Never obstruct the fl ow of dilution/ventilation air. If you
have any doubts or questions at all, call your gas supplier.
Failure to provide the proper amounts of air can result in
a fi re or explosion and cause property damage, serious
bodily injury or death. The combustion and dilution air
inlets are shown in Figure 2.
Important: Power Vented water heaters require air for
combustion and dilution air for the blower.
UNCONFINED SPACE
An Unconfi ned Space is one whose volume is not less
than 50 cubic feet per 1,000 Btu/hr (4.8m
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
fi replaces should also be considered in determining the
adequacy of a space to provide combustion, ventilation
and dilution air.

UNUSUALLY TIGHT CONSTRUCTION

In unconfi ned spaces in buildings, infi ltration may be
adequate to provide air for combustion, ventilation and
dilution of fl ue gases. However, in buildings of unusually
tight construction (e.g., weather stripping, heavily
insulated, caulked, vapor barrier, etc.) additional air must
be provided using the methods described in the "Confi ned
Space" section that follows.
CONFINED SPACE
A Confi ned Space is one whose volume is less than 50
cubic feet per 1,000 Btu/hr (4.8m
rating of all appliances installed in the space.
Openings must be installed to provide fresh air for
combustion, ventilation and dilution in confi ned spaces.
The required size for the openings is dependent on the
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/kW) of the
3
/kW) of the total input
3
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