Product Overview

COMPLIANCE – These models meet the thermal efficency and standby loss requirements
of the U.S. Department of Energy and current edition ASHRAE/IESNA 90.1.
FEATURES
ALL NON-FERROUS WATERWAYS – All castings are made of Bronze or Brass. All water
tubes are made from copper. Brazed joints or flare union construction make the heater immune
to the effects of thermal shock and thermal cycling. A great boiler for domestic hot water
supply systems.
EFFICIENT COPPER COIL COMBUSTION CHAMBER – The 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.
COPPER HEAT EXCHANGER – 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.
BURKAY BURNER MAXIMIZES EFFICIENCY – 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.
GAS VALVES – Slow opening redundant gas valves ensure smooth light-off without
flame roll-out or pilot outage.
THERMAL BALANCER – Patented pump delay system that allows boiler and pump to
run simultaneously but 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.
AUTOMATIC SAFETY CONTROLS AND ELECTRONIC IGNITION – Proven
pilot ignition system provides flame failure response in under one (1) second. Redundant high
limit controls and gas valves assure safe shutoff in the event of overheating or flame failure.
Requires 120V 60Hz, maximum inlet gas pressure of 14" WC and activation of heater by external
temperature control.
WORKING PRESSURE – ASME approved, hydrostatically tested and certified for 160 psi.
COMMERCIAL BOILERS
HW-300
THRU
HW-670
Domestic Hot Water
Boilers
HW - INDOOR
INSTALLATION
ONLY
LIMITED WARRANTY OUTLINE – Consult written warranty or A. O. Smith.
®
80% THERMAL EFFICIENCY
Revised November 2012
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AOSDG25600
Low Lead Content
H
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