A.O. Smith 650A, 740A warranty Hard Water, Clearances, AIR Requirements, Venting, Confined Space

Units, which are to be installed on combustible flooring, must be supported by a full layer of hollow concrete blocks, from 8” (203.2 mm) to 12” (304.8 mm) thick and extending 12” (304.8 mm) minimum beyond the heater in all directions. The concrete blocks must provide an unbroken concrete surface under the heater with the hollows running continuously and horizontally. A 3/16-inch steel plate must cover the concrete blocks, see Figure 2.

NOTE: If electrical conduits run under the floor of the proposed heater location, insulate the floor as recommended above.

For appliances installation locations with elevations above 2000 feet (609.6 m), refer to HIGH ALTITUDE INSTALLATIONS section.

PROPER INSTALLATION ON COMBUSTIBLE FLOORING

FIGURE 2.

HARD WATER

Where hard water conditions exist, water softening or the threshold type of water treatment is recommended. This will protect the dishwasher, Coffee urns, water heaters, water piping and other equipment.

See MAINTENANCE section for details of tank cleanout procedure.

CLEARANCES

These heaters are designed for installation on non-combustible flooring in an alcove with clearances to combustible construction of 6” (152.4 mm) from the sides and rear, 24” (610 mm) from the top with a 6” (152.4 mm) minimum between vent pipe and ceiling. Minimum clearance from flue pipe to combustible material is 6” (152.4 mm), see Figure 3.

PROPER INSTALLATION CLEARANCES

FIGURE 3.

A clearance of 30” (762 mm) shall be maintained from serviceable parts, such as power burners, relief valves flue baffles, thermostats or drain valves.

AIR REQUIREMENTS

KEEP APPLIANCE AREA CLEAR AND FREE OF COMBUSTIBLE MATERIALS,GASOLINEANDOTHERFLAMMABLEVAPORSAND LIQUIDS.

DO NOT OBSTRUCT THE FLOW OF COMBUSTION OR VENTILATING AIR.

WARNING

FOR SAFE OPERATION PROVIDE ADEQUATE AIR FOR COMBUSTION AND VENTILATION. AN INSUFFICIENT SUPPLY OF AIR WILL CAUSE RECIRCULATION OF COMBUSTION PRODUCTS RESULTING IN AIR CONTAMINATION THAT MAY BE HAZARDOUSTO LIFE. SUCH A CONDITION OFTENWILL RESULT IN A YELLOW, LUMINOUS BURNER FLAME, CAUSING CARBONING OR SOOTING OF THE COMBUSTION CHAMBER, BURNERS AND FLUE TUBES AND CREATES A RISK OF ASPHYXIATION.

Where an exhaust fan is installed in the same room with a heater, sufficient openings for air must be provided in the walls.

UNDERSIZED OPENINGS WILL CAUSE AIR TO BE DRAWN INTO THE ROOM THROUGH THE CHIMNEY, CAUSING POOR COMBUSTION. SOOTING MAY RESULT IN SERIOUS DAMAGE TO THE HEATER AND RISK OF FIRE OR EXPLOSION.

UNCONFINED SPACE

In buildings of conventional frame, brick or stone construction, unconfined spaces may provide adequate air for combustion and ventilation.

If the unconfined space is within a building of tight construction, (building using the following construction: weather stripping, heavy insulation, caulking, vapor barrier, etc.), air for combustion and ventilation must be obtained from outdoors or spaces freely communicating with the outdoors. The installation instructions for confined spaces in tightly constructed buildings must be followed to ensure adequate air supply.

CONFINED SPACE

When drawing combustion and dilution air from inside a conventionally constructed building to a confined space, such a space shall be provided with two permanent openings, ONE IN OR WITHIN 12 INCHES (304.8 mm) OF THE ENCLOSURE TOP AND ONE IN OR WITHIN 12 INCHES (304.8 mm) OF THE ENCLOSURE BOTTOM. Each opening shall have a free area of at least one square inch per 1000 Btuh of the total input of all appliances in the enclosure, but not less than 100 square inches.

If the confined space is within a building of tight construction, air for combustion and ventilation must be obtained from outdoors. When directly communication with the outdoors through vertical ducts, two permanent openings, located in the above manner, shall be provided. Each opening shall have a free area of not less than one square inch per 4000 Btuh of the total input of all appliances in the enclosure.

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.

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