AO Smith® HW-520-N Industrial Gas Fired Water Heater, 520000 Btu/hr, 152 kW, Natural Gas, Propane Gas

Hot water supply boiler for domestic hot water purposes shall be model no as manufactured by AO Smith® or an approved equal. Boilers shall be gas fired and design certified by an ANSI approved/accredited independent rating laboratory, capable of supplying gph at 100 deg F temperature rise equipped to burn gas, with input rating of BTU/hr. And bearing the ASME code symbol. Boilers shall be up flow type having all non-ferrous waterways and employing a copper finned heat exchanger and a tightly wound copper coil combustion chamber with 160 psi working pressure rating. Boilers shall be equipped with an electric gas valve of the step opening-type, an adjustable limit control which will break the electric circuit on temperature rise, intermittent ignition with one second shutdown in the event of pilot flame failure, a gas pressure regulator properly set for the gas to be supplied and a coil limit switch for shut-off in event of excessive water temperature, a certified draft diverter and a fully illustrated instruction manual. Certified for installation on combustible flooring. Outer jacket shall be of baked enamel finish. The coil, heat exchanger and burner shall have a 5 year limited warranty as outlined in the written warranty.

AO Smith® Industrial Gas Fired Water Heater, Model: HW-520, 520000 Btu/hr, 152 kW, 42 gpm Flow Rate, 6 in Vent, 120 V, 60 Hz, NPT Connection, 160 psi, Natural Gas, Propane Gas Fuel, Pilot Ignition System, Finish: Black Enamel-Coated, 100 deg F, 68-5/16 in H x 36-1/2 in D

• All castings are made of bronze or brass
• All water tubes are made from copper
• Brazed joints or flare union construction make the boiler immune to the effects of thermal shock and thermal cycling
• A great boiler for domestic hot water supply
• The efficient copper coil combustion chamber is a heat exchanger formed from a two passage coil of tightly wound continuous copper tube
• Water circulating through this coil surrounds the main burner and captures the Radiant™ heat
• A wrap of insulation on the outside of the coil retains the heat captured by the circulating water
• Directly above the coil and the main burner is a compact, horizontal, copper fin tube heat exchanger
• The flue gases must pass through this efficient heat exchanger before leaving the boiler
• This unique burkay coil and heat exchanger design provide maximum heat transfer and proven field durability
• The patented burkay burner uses primary air injection at up to 72 individual orifices plus secondary entrainment of air
• Approved for installation on combustible floors as shipped from factory
• Slow opening redundant gas valves ensure smooth light-off without flame roll-out or pilot outage
• Patented pump delay system that allows boiler and pump to run simultaneously
• Delays pump shut-off at end of heating cycle to remove usable heat from the heat exchanger and reduce the scale forming tendencies of motionless hot water
• Proven pilot ignition system provides flame failure response in under one second
• Redundant high-limit controls and gas valves assure safe shut-off in the event of overheating or flame failure
• Requires 120 V, 60 Hz, maximum inlet gas pressure of 14 in-WC and activation of boiler by external temperature control
• ASME approved, hydrostatically tested and certified for 160 psi
• These model meet the thermal efficiency and standby loss requirements of the U. S. Department of energy and current edition ASHRAE/IESNA 90.1

• Instruction/Installation Manual https://assets.unilogcorp.com/267/ITEM/DOC/AO_Smith_HW_300_N_Instruction_Installation_Manual.pdf
• Specification Sheet https://assets.unilogcorp.com/267/ITEM/DOC/AO_Smith_HW_300_N_Specification_Sheet.pdf