A.O. Smith W/HOT ALL AIR from Inside Buildings See, ALL AIR from Outdoors See Figures 7, 8

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a free area of one square inch per 1000 Btu/hr (22 cm2/kW) of the total input of all appliances in the enclosure, but not less than 100 square inches (645 cm2).

If the confined space is within a building of tight construction, air for combustion and ventilation must be obtained from outdoors. When directly communicating with the outdoors or communicating 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 Btu/hr (5.5 cm2/kW) of total input of all appliances in the enclosure. If horizontal ducts are used, each opening shall have a free area of not less than one square inch per 2000 Btu/hr (11cm2/kW) of the total input of all appliances in the enclosure.

A. ALL AIR FROM INSIDE BUILDINGS: (See Figure 5 and 6)

The confined space shall be provided with two permanent openings communicating directly with an additional room(s) of sufficient volume so that the combined volume of all spaces meets the criteria for an unconfined space. The total input of all gas utilization equipment installed in the combined space shall be considered in making this determination. Each opening shall have a minimum free area of one square inch per 1,000 Btu per hour (22 cm2/kW) of the total input rating of all gas utilization

equipment in the confined space, but not less than 100 square inches (645 cm2). One opening shall commence within 12 inches (30 cm) of the top and one commencing within 12 inches (30 cm) of the bottom of the enclosures.

FIGURE6.

B. ALL AIR FROM OUTDOORS: (See Figures 7, 8 and 9)

The confined space shall be provided with two permanent openings, one commencing within 12 inches (30 cm) of the top and one commencing within 12 inches (30 cm) from the bottom of the enclosure. The openings shall communicate directly, or by ducts, with the outdoors or spaces (crawl or attic) that freely communicate with the outdoors.

1.When directly communicating with the outdoors, each opening shall have a minimum free area of 1 square inch per 4,000 Btu per hour (5.5 cm2/kW) of total input rating of all equipment in the enclosure, see Figure 7.

FIGURE7.

2.When communicating with the outdoors through vertical ducts, each opening shall have a minimum free area of 1 square inch per 4,000 Btu per hour (5.5 cm2/kW) of total input rating of all equipment in the enclosure, see Figure 8.

3.When communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch per 2,000 Btu per hour (11 cm2/kW)) of total input rating of all equipment in the enclosure, see Figure 9.

FIGURE8.

4.When ducts are used, they shall be of the same cross-sectional area as the free area of the openings to which they connect. The minimum short side dimension of rectangular air ducts shall not be less than 3 inches (7.6 cm), see Figure 9.

FIGURE9.

5.Alternatively a single permanent opening may be used when communicating directly with the outdoors, or with spaces that freely communicate with the outdoors. The opening shall have a minimum free area of 1 square inch per 3,000 BTU per hour (8.3 cm2/kW) of total input rating of all equipment in enclosure. See Figure 9A.

FIGURE9A.

6.Louvers and Grilles: In calculating free area, consideration shall be given to the blocking effect of louvers, grilles or screens protecting openings. Screens used shall not be smaller than 1/4 inch (6.4 mm) mesh. If the free area through a design of louver or grille is known, it should be used in calculating the size opening required to provide the free area specified. If the design and free area is not known, it may be assumed that wood louvers will be 20-25 percent free area and metal louvers and grilles will have 60-75 percent free area. Louvers and grilles shall be fixed in the open position or interlocked with the equipment so that they are opened automatically during equipment operation.

7.Special Conditions Created by Mechanical Exhausting or Fireplaces: operation of exhaust fans, ventilation systems, clothes dryers or fireplaces may create conditions requiring special attention to avoid unsatisfactory operation of installed gas utilization equipment.

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Contents Power Vented GAS Models W/HOT Surface Ignition Commercial GAS Water HeatersSafe INSTALLATION, USE and Service Important DefinitionsGeneral Safety General Safety Table of Contents IntroductionTypical Installation Replacement Parts and Deliming ProductsRelief Valve Elbow Access Door Condensate Hose and Drain PAN ROUGH-IN-DIMENSIONS Rough-In-DimensionsCapacity and Gas and Electrical Characteristics Mixing Valve Usage Locating the NEW Water Heater Facts to Consider about the LocationInsulation Blankets ALL AIR from Inside Buildings See ALL AIR from Outdoors See Figures 7, 8Installing the NEW Water Heater Chemical Vapor CorrosionWater Piping TEMPERATURE-PRESSURE Relief Valve Valve and Pipe Insulation if suppliedGAS Piping with Flexible Connector GAS PipingVent Pipe Assembly Sediment TrapsFilling the Water Heater VentingHorizontal Vent Clearances Canadian Horizontal Vent Clearances Vent Pipe TerminationVent Hoods MAY be Extremely HOT During Operation Planning the Vent System CondensateBlower Assembly Installation Installation of Vent SystemVent Terminal INSTALLATION, Sidewall Power Vent Wiring Schematic Figure Vent Termination FigureInstallation of Vent SYSTEM, Sidewall Installation of Vertical Vent SystemVent Attenuation Assembly Installation Vertical VAA Installations RecommendedInch vent Vertical VAA Installations Inch vent Horizontal VAA InstallationsVent Pipe Preparation Recommended BRUSH* Size for Primer Cement ApplicationsStep B Step EStep F Step GPower Before Servicing Burner. Do not try to light the burner by handWhat to do if YOU Smell GAS Do not TRY to Light the Burner by HandTemperature Regulation Temperature Indicators Temperature Adjustment ButtonsDisplay D E FFor Your Information Start UP ConditionsOperational Conditions Periodic Maintenance Burner CleaningVenting System Inspection Burner Operation and InspectionTEMPERATURE-PRESSURE Relief Valve Operation Anode ROD InspectionDraining Service Leakage CheckpointsTroubleshooting Guidelines Trouble ShootingD E F Troubleshooting Guidelines Service and Repair Expenses Claim ProcedureTank ALL Other Parts

W/HOT specifications

A.O. Smith, a leading manufacturer of water heating solutions, has made its mark in the industry with innovative products that combine efficiency, reliability, and advanced technology. Among its standout offerings is the A.O. Smith W/HOT series, designed to meet the diverse needs of residential and commercial customers.

The W/HOT series showcases a variety of tankless water heaters characterized by their ability to provide endless hot water on demand. Unlike traditional tank water heaters, which can run out of hot water during heavy usage, the W/HOT series ensures a constant supply, making it an ideal choice for families and businesses with high hot water needs. This feature not only enhances convenience but also optimizes energy usage by eliminating the standby heat loss associated with storage tanks.

One of the key technologies integrated into the W/HOT series is the microprocessor control system. This intelligent technology allows the unit to monitor water usage patterns and adjust operation accordingly. By optimizing heating cycles based on actual demand, this feature helps improve energy efficiency, resulting in lower utility bills without compromising performance.

The W/HOT series also incorporates advanced heat exchanger technology, enabling rapid heating of water as it passes through the system. This means minimal wait time for hot water and reduced energy consumption, as the unit only heats water when it is needed. The heat exchangers are designed for durability and effective heat transfer, helping to extend the overall lifespan of the unit.

Safety is a top priority in the design of A.O. Smith water heaters. The W/HOT series is equipped with multiple safety features, including a built-in thermal shut-off switch and safety sensors that prevent overheating. Additionally, the units are designed to comply with industry standards and regulations, ensuring peace of mind for users.

Installation flexibility is another defining characteristic of the W/HOT series. These tankless water heaters can be installed in various locations, requiring minimal space compared to traditional units. Their compact design makes them suitable for tight spaces, such as closets or utility rooms.

Overall, the A.O. Smith W/HOT series represents a commitment to innovation and quality in water heating solutions. Its combination of tankless design, advanced technology, and safety features makes it an excellent choice for those seeking efficient and reliable hot water access. Whether for residential or commercial use, A.O. Smith continues to lead the way in delivering top-tier water heating solutions that meet the evolving needs of consumers.
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