A.O. Smith HW-300, HW-399, HW-420, HW-520, HW-670 Installation Manual

HW BURKAY HOT WATER SUPPLY BOILER

HW - 300/399/420/520/670

Floor standing, gas red.

• All castings are made of Bronze or Brass

• All water tubes are made from copper

• Brazed joints or are union construction make the boiler immune to the effects of thermal shock and thermal cycling

• A great boiler for domestic hot water supply

• The efcient 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 n tube heat exchanger

• The ue gases must pass through this efcient heat exchanger before leaving the boiler

• This unique Burkay coil and heat exchanger design provide maximum heat transfer and proven eld durability

• The patented Burkay burner uses primary air injection at up to 72 individual orices plus secondary entrainment of air

• Approved for installation on combustible oors as shipped from factory.

• Slow opening redundant gas valves ensure smooth light-off without ame roll-out or pilot outage

• 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

• Proven pilot ignition system provides ame failure response in under one (1) second

• Redundant high limit controls and gas valves assure safe shutoff in the event of overheating or ame failure

• Requires 120V 60Hz, maximum inlet gas pressure of 14” WC and activation of boiler by external temperature control

• ASME approved, hydrostatically tested and certied for 160 psi

• Ships with ASME 125 psi relief valve

• These models meet the thermal efciency and standby loss requirements of the U.S. Department of Energy and current edition ASHRAE/IESNA 90.1.

SAMPLE SPECIFICATION

Hot Water Supply Boiler for domestic hot water purposes shall be Model(s) No. __________________ as manufactured by A. O. Smith or an approved equal. Boiler(s)

shall be gas-red, and design certied by an ANSI approved/accredited independent rating laboratory, capable of supplying _____ gph at 100°F temperature rise equipped to burn __________ gas, with input rating of _____ BTU/hr. and bearing the ASME code symbol. Boiler(s) shall be up ow type having all nonferrous waterways, and employing a copper nned heat exchanger and a tightly wound copper coil combustion chamber with 160 psi working pressure rating. Boiler(s) 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 (1) second shutdown in the event of pilot ame 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 certied draft diverter and a fully illustrated instruction manual. Certied for installation on combustible ooring. Outer jacket shall be of baked enamel nish. The coil, heat exchanger and burner shall have a ve year limited warranty as

outlined in the written warranty.

INSTALLATION & DIMENSIONS

LOCATION OF MANUAL MAIN SHUTOFF VALVE OUTSIDE JACKET WHEN CODE REQUIRE (NOT SUPPLIED)

Dimensions

in inches

HW-300 HW-399 HW-420 HW-520 HW-670

Models

A Overall height 65 (1651) 57-1/8 (1451) 57-1/8 (1451) 68-5/16 (1735) 68-5/16 (1735)

B Height on Top of Jacket 43-1/4 (1099) 45-1/8 (1146) 45-1/8 (1146) 56-1/4 (1429) 56-1/4 (1429)

C Floor to Center Line Water Outlet 36 (914) 38-3/4 (984) 38-3/4 (984) 46 (1168) 46 (1168)

D Diameter of Jacket 25-1/4 (641) 27 (686) 27 (686) 27 (686) 27 (686)

E Floor to Center Line Gas Inlet 12 (305) 12 (305) 12 (305) 1 2 (305) 12 (305)

F Draft Diverter Outlet Diameter 8 (203) 10 (254) 10 (254) 10 (254) 12 (305)

G Floor to Center Line Gas Inlet 16-1/2 (419) 16-3/4 (425) 16-3/4 (425) 8 (457) 18 (457)

H Overall Depth 29-5/8 (753) 31-1/2 (800) 31-1/2 (800) 36-1/2 (927) 36-1/2 (927)

J Support Height 9 (229) 9 (229) 9 (229) 9 (229) 9 (229)

K Width of Control String (approx.) 14 (356) 14 (356) 14 (356) 11 (279) 11 (279)

L Pipe Size of Water Inlet (NPT) 1-1/4 1-1/2 1-1/2 2 2

M Pipe Size of Water Outlet (NPT) 1-1/4 1-1/2 1-1/2 2 2

N Pipe Size of Gas Inlet (NPT) 3/4 3/4 1 1 1

P Control String Plus 1/2 Jacket Diameter (approx.) 26-5/8 (676) 27-1/2 (699) 27-1/2 (699) 24-1/2 (622) 24-1/2 (622)

S Horizontal Lenght between Water Inlet & Outlet 5-3/8 (137) 5-1/2 (140) 5-1/2 (140) 5-3/4 (146) 5-3/4 (146)

T Control string from Jacket 5 (127) 5 (127) 5 (127) 7 (178) 7 (178)

Approx. shipping weight lbs. (kg) 250 (113) 301 (137) 301 (137) 381 (173) 381 (173)

BTU input/output

Temperature rise and pressure drop

20°F rise 30°F rise 40°F rise

Models

Input rating

BTU/hr Nat &

Prop. (LP) gas

Output rating

BTU/hr Nat & Prop. (LP) gas

GPM

PD-FT

head

GPM

PD-FT

head

GPM

PD-FT

HW 300 300,000 240,000 24 8 16 3 12 2

HW 399 399,000 319,200 32 16 21 7 16 5

HW 420 420,000 336,000 34 18 22 8 21 5.5

HW 520 520,000 416,000 42 12 28 5 26 4

HW 670 Nat 660,000 528,000 53 22 35 10 26 5.5

HW 670 Prop. 670,000 536,000 54 22 36 10 27 5.5

Models

HW 300

HW 399

HW 420

HW 520

Type of

gas

Natural

Propane

Natural

Propane

Natural

Propane

Natural

Propane

Input °F 20 40 50 60 70 80

BTU/hr kW °C (11) (22) (28) (33) (39) (44)

300,000 88 GPH 1,455 727 582 485 416 364

LPH 5,506 2,753 2,202 1,835 1,573 1,377

399,000 117 GPH 1,935 967 744 645 553 484

LPH 7,323 3,662 2,929 2,441 2,092 1,831

420,000 123 GPH 2,036 1,018 815 679 582 509

LPH 7,708 3,854 3,083 2,569 2,202 1,927

520,000 152 GPH 2,521 1,261 1,008 840 720 630

LPH 9,544 4,772 3,818 3,181 2,727 2,386

660,000 193 GPH 3,200 1,600 1,280 1,067 914 800

HW 670 Natural

HW 670 Propane

670,000 196 GPH 3,248 1,624 1,299 1,083 928 812

LPH 12,113 6,057 4,845 4,038 3,461 3,028

LPH 12,297 6,148 4,919 4,099 3,513 3074

head

FIGURE 1. DIMENSIONS

EXTRA OPENING FOR THERMOMETER AND PRESSURE RELIEF VALVE HW-520 AND HW-670

Data subject to change

ME/HW300-670/01