Facts To Consider About Location; Insulation Blankets; Combustion Air And Ventilation; Appliances In Unconfined Spaces - A.O. Smith RESIDENTIAL GAS WATER HEATERS Instruction Manual

in an alcove or closet, the entire floor must be covered by the panel.
Failure to heed this warning may result in a fire hazard.
Minimum clearances between the water heater and combustible
construction are 0 inch at the sides and rear, 5.5" (14.0 cm) from the front
and 12" (30.5 cm) from the top. (Standard clearance.) If clearances
stated on the heater differ from standard clearances, install water
heater according to clearances stated on the heater.
Adequate clearance 24" (61.0 cm) for servicing this appliance should be
considered before installation, such as changing the anodes, etc.
A minimum clearance of 5.5" (14.0 cm) must be allowed for access to
replaceable parts such as the thermostats, drain valve and relief valve.
When installing the heater, consideration must be given to proper
location. Location selected should be as close to the wall as practicable
and as centralized with the water piping system as possible.
FIGURE 4.

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 the standby heat loss
encountered with storage tank heaters. Your water heater meets or
exceeds the Energy Policy Act 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 identification of components
mentioned below, see Figure 1). Failure to follow these instructions
can restrict the air flow required for proper combustion, potentially
resulting in fire, 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 temperature & pressure
relief valve.
• Do not allow insulation to come within 2" (5.1 cm) of the floor to
prevent blockage of combustion air flow to the burner.
• Do not cover the instruction 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 flow.

coMBustIon aIr and ventIlatIon

A gas water heater cannot operate properly without the correct amount
of air for combustion. Do not install in a confined area such as a closet,
unless you provide air as shown in the "Facts to Consider About
Location" section. 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 death, serious bodily injury, or property damage.
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 (s) be installed direct vent so that
all air for combustion and ventilation is taken from outdoors.
Propellants of aerosol sprays and volatile compounds, (cleaners,
chlorine based chemicals, refrigerants, etc.) in addition to being highly
flammable 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.

applIances In unconfIned spaces

unconfIned space is space whose volume is not less than
50 cubic feet per 1,000 Btu per hour (4.8 cubic meters per kW) of the
aggregate input rating of all appliances installed in that 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.
In unconfined spaces in buildings, infiltration may be adequate to
provide air for combustion, ventilation and dilution of flue gases.
However, in buildings of tight construction (for example, weather
stripping, heavily insulated, caulked, vapor barrier, etc.), additional air
may need to be provided using the methods described in "Appliances
in Confined Space" that follows."

applIances In confIned spaces

confIned space is a space whose volume is less than 50 cubic
feet per 1,000 Btu per hour (4.8 cm per kW) of the aggregate input
rating of all appliances installed in that space.
When drawing combustion air from inside a conventionally constructed
building to a confined space, such a space shall be provided with
two permanent openings. ONE WITHIN 12 INCHES (30 cm) OF
THE ENCLOSURE TOP AND ONE WITHIN 12 INCHES (30
cm) OF THE ENCLOSURE BOTTOM. Each opening shall have
11
FIGURE 5.