not known, the latest edition of National Fuel Gas Code ANSI Z223.1 recommends using figures of 20-25 percent free area for wood louvers or 60-75 percent for metal grills or louvers.

UNCONFINED SPACE

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

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, ventilation, and venter dilution must be obtained from outdoors. The installation instructions for confined spaces must be followed.

WATER (POTABLE) HEATING AND SPACE HEATING

1.All piping components connected to this unit for space heating applications shall be suitable for use with potable water.

2.Toxic chemicals, such as those used for boiler treatment, shall NEVER be introduced into this system.

3.This unit may NEVER be connected to any existing heating system or component(s) previously used with a non-potable water heating appliance.

4.When the system requires water for space heating at temperatures higher than required for domestic water purposes, a tempering valve must be installed. Please refer to Fig. 2 for suggested piping arrangement.

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 WITHIN 12 INCHES OF THE ENCLOSURE TOP AND ONE WITHIN 12 INCHES OF THE ENCLOSURE BOTTOM. Each opening shall have a free area of 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, ventilation and power venter dilution 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 Btuh of the 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 Btuh of the total input of all appliances in the enclosure.

WATER CONNECTIONS

Refer to figure 1 for typical installation. A suitable pipe thread sealant must be used to prevent leakage.

FIGURE2

CLOSED WATER SYSTEM

A closed system will exist if a back-flow preventer (check valve), pressure reducing valve, or other similar device is installed in the cold water line between the water heater and the street main (or well). Excessive pressure may develop due to the thermal expansion of heated water causing premature tank failure or intermittent relief valve operation. This type of failure is not covered by the limited warranty. An expansion tank may be necessary in the cold water supply to alleviate this situation, see Fig. 1. Contact the local plumbing authority.

If the temperature and pressure relief valve on the appliance discharges periodically, this may be due to thermal expansion in a closed water supply system. Contact the water supplier or local plumbing inspector on how to correct situation. DO NOT PLUG THE TEMPERATURE AND PRESSURE RELIEF VALVE.

GAS CONNECTIONS

The minimum gas supply pressure for input adjustment is 5.0" W.C. for natural gas (11.0" W.C. for propane).

THEHEATERISNOTINTENDEDFOROPERATIONATHIGHERTHAN 14" WATER COLUMN SUPPLY PRESSURE. EXPOSURE TO HIGHER GAS SUPPLY PRESSURE MAY CAUSE DAMAGE TO THE CONTROL WHICH COULD RESULT IN FIRE OR EXPLOSION. If overpressure has occurred such as through improper testing of gas lines or emergency malfunction of the supply system, the control must be checked for safe operation. Make sure that the outside vents on the supply regulators and the safety vent valves are protected against blockage. These are parts of the gas supply system not the heater. Vent blockage may occur during ice storms.

IT IS IMPORTANT TO GUARD AGAINST CONTROL FOULING FROM CONTAMINANTS IN THE GAS WAYS. SUCH FOULING MAY CAUSE IMPROPER OPERATION, FIRE OR EXPLOSION.

All piping must comply with local codes and ordinances or with the National Fuel Gas Code (ANSI Z223.1 NFPA-54) whichever applies.

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A.O. Smith GPS-75 owner manual Unconfined Space, Water Potable Heating and Space Heating, Confined Space, Water Connections
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GPS-75 specifications

The A.O. Smith GPS-75 is a state-of-the-art gas water heater designed to deliver efficient and reliable hot water solutions to residential and light commercial users. With its sleek design and advanced technology, this unit stands out in the competitive water heating market.

One of the primary features of the GPS-75 is its impressive 75-gallon capacity, making it ideal for larger households or businesses that require a substantial volume of hot water. This water heater delivers a first-hour rating of up to 91 gallons, ensuring that you will always have enough hot water on demand, even during peak usage times.

The GPS-75 utilizes a high-efficiency gas burner that operates at an energy factor of 0.67, which helps to minimize energy costs while providing robust heating performance. This means that users can enjoy powerful hot water output without having to worry about skyrocketing energy bills. Additionally, the unit is equipped with a state-of-the-art electronic ignition system that ensures reliable startup and operation. This feature eliminates the need for a pilot light, enhancing safety and energy efficiency.

In terms of durability, the GPS-75 features a glass-lined interior which protects the tank from rust and corrosion. This adds to the unit's longevity and reduces the need for maintenance and replacement. The water heater also comes with insulating foam in the tank and a special temperature and pressure relief valve to enhance safety.

Another notable technology included in the GPS-75 is its advanced diagnostics feature. This system is designed to monitor and diagnose problems, allowing for quick troubleshooting and minimizing downtime. This is especially useful for service professionals and homeowners alike, as it facilitates efficient maintenance and reduces unexpected repair costs.

The GPS-75 also has an environmentally friendly design, meeting stringent energy efficiency guidelines. This aligns with the growing demand for sustainable solutions in modern homes and businesses.

In summary, the A.O. Smith GPS-75 gas water heater combines an impressive 75-gallon capacity, high efficiency, and advanced safety features to offer users a reliable and economical hot water solution. With its innovative technologies and durable construction, it stands as a strong contender in the water heating industry. Whether for residential or commercial use, the GPS-75 ensures that hot water is always available when needed.
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