Commercial Gas Boilers
MODELS
DW-720
through
DW-1810
UP TO 82% EFFICIENT HOT WATER SUPPLY BOILERS
The Dura-Max® series offers excellent performance and low-profile design flexibility for both
new construction and retrofit applications. A double-row, integral-finned copper tube heat
exchanger provides exceptional heat transfer efficiency. Each unit features a small footprint
with a built-in draft diverter for extra clearance to simplify installation. Reliable, quiet, drawer-
mounted stainless steel burners resist corrosion, improve access for easy maintenance.
FEATURES
100% ALL NON-FERROUS HEAT EXCHANGER WATERWAYS
• All waterways 100% copper, brass or bronze
• Won’t rust, resists thermal shock
• Heavy-duty bronze castings and copper heat exchange tubes
• Bronze removable return bends for easy access and inspection
of individual tubes
GASKETLESS WET SECTION
• Unique “O”-ring design compresses to form water-tight seal
positioned away from and outside the combustion chamber
• Isolated location offers optimum protection and years of service
DRAWER-MOUNTED, STAINLESS STEEL DURA-MAX® BURNERS
• Quiet operation and efficient, reliable design
• Protects against corrosion and condensation deterioration
• Easy slide-out burner tray simplifies cleaning and maintenance
COMPACT, LOW-PROFILE DESIGN
• Built-in draft diverter provides extra clearance in tight, retrofit installations
• Clean, compact jacket design for easy access and assembly
• Cool to touch and approved for combustible floors
INTERMITTENT ELECTRONIC IGNITION
• Eliminates standing pilot, saves energy
• Includes power ON/OFF switch
FACTORY-MOUNTED BRONZE-FITTED PUMP
• Ensures proper flow rates and efficient heat transfer
• Thermal Balancer Pump Delay Switch cycles pump,
reduces standby heat loss
MAXIMUM HYDROSTATIC WORKING PRESSURE: 160 PSI
MEETS ASHRAE/IESNA 90.1-2004
FIVE-YEAR HEAT EXCHANGER LIMITED WARRANTY
• For complete information, consult written warranty or contact A. O. Smith
Page 1 of 4
Revised November 2009
AOSDG25300
Commercial Gas Boilers
OTHER DURA-MAX® FEATURES
l
l
MANUAL RESET, HIGH LIMIT ASME-RATED PRESSURE RELIEF VALVE 125#
l
l
l
MINIMUM CLEARANCES TO COMBUSTIBLES -
ALL MODELS
SAFETY FLOW SWITCH REDUNDANT GAS VALVE
DURA-MAX® OPTIONS
Inches
12
CM
30.5
45.7
q CSD-1
q NEW YORK CODE
TOP
q CALIFORNIA CODE
WATERSIDE
18
q PANEL MOUNTED INLET/OUTLET DIAL
q THERMOMETERS AND PRESSURE GAUGE
q MOTORIZED MODULATING FIRE
q DUAL STAGE FIRING
BLANK SIDE
REAR
6
6
6
15.5
15.5
15.5
q RIGHT HAND GAS AND/OR WATER CONNECTIONS
q CUPRO-NICKEL HEAT EXCHANGER
q SIDEWALL VENT KITSALL-BRONZE PUMP
q HIGH VELOCITY HARD WATER PUMP
q LOW WATER CUTOFF
VENT
FRONT
Alcove
INPUT AND RECOVERY
RECOVERY -GALLONS OR
LITRES PER HOUR AT
DEGREE RISE
BTU
INPUT
PER
GPH
OR
LPH
MODEL
NUMBER
40°F
100°F
56°C
707
140°F
HOUR*
22°C
78°C
GPH
1767
505
DW-720
720,000
LPH
GPH
LPH
GPH
LPH
GPH
LPH
GPH
LPH
GPH
LPH
GPH
LPH
GPH
LPH
GPH
6690
2062
2676
825
3122
943
3568
1073
4063
1203
4552
1342
5079
1435
5432
1561
5910
1755
1911
589
2230
673
2548
767
2902
859
3252
958
3628
1025
3880
1115
4221
1254
DW-840
DW-960
DW-1080
840,000
960,000
7805
2356
8920
2684
1,080,000
10,158
3007
DW-1210
DW-1350
DW-1480
DW-1610
1,210,000
1,350,000
1,480,000
1,610,000
11,381
3355
12,698
3588
13,581
3903
14,774
4388
DW-1810
1,810,000
LPH
16,609
6644
4746
* Natural gas only
Gas supply pressure: 13:8” w.c. maximum, 5.5” w.c. minimum
Electrical requirements: 120 VAC, 15 Amps
Revised November 2009
Page 2 of 4
AOSDG25300
Commercial Gas Boilers
INPUT/OUTPUT, FLOW RATE (GALLONS AND LITRES PER MINUTE) AND PRESSURE DROP
20°F/11°C DELTA T
MAXIMUM FLOW PRESSURE DROP
30°F/17°C DELTA T
MAXIMUM FLOW PRESSURE DROP
40°F/22°C DELTA T
MODEL
NUMBER
BTU/HR.
INPUT
BTU/HR.
OUTPUT
MAXIMUM FLOW PRESSURE DROP
GPM
59
LPM
223
260
297
339
379
423
453
FEET
3.5
4.8
6.8
4.5
5.3
6.8
7.9
METERS
1.1
GPM
39
LPM
149
173
198
226
253
282
302
FEET
1.7
2.1
3.3
2.1
2.7
3.2
3.9
METERS
0.5
DW-720
DW-840
720,000
840,000
583,200
680,400
777,600
885,600
992,200
1,107,000
1,184,000
29
34
39
45
50
56
60
111
130
149
169
190
212
226
1.0
1.5
1.9
1.4
1.6
1.8
2.1
0.3
0.5
0.6
0.4
0.5
0.5
0.6
69
1.5
46
0.6
DW-960
960,000
79
2.1
52
1.0
DW-1080
DW-1210
DW-1350
DW-1490
1,080,000
1,210,000
1,350,000
1,490,000
89
1.4
60
0.6
100
112
120
1.6
67
0.8
2.1
75
1.0
2.4
80
1.2
DW-1610
DW-1810
1,610,000
1,288,000
1,448,000
130
492
9.5
2.9
3.7
87
98
328
5.0
6.2
1.5
65
246
3.0
3.9
0.9
1.2
1,810,000
146
554
12.0
369
1.9
73
277
Pressure drop shown is loss through boiler only, and does not include any additional piping.
DIMENSIONS AND SHIPPING WEIGHTS
DIMENSIONS
MODEL
NUMBER
INCHES OR
CM
SHIPPING
WEIGHT
A
B
C
D
E
F
G
H
L
M
N
P
Inches
CM
46-1/2
29-5/8 54-3/4
75.2 139.1
29-5/8 54-3/4
75.2 139.1
29-5/8 54-3/4
1-1/4
3.2
7-3/4
15-1/2 17-1/4
39.4 43.8
15-1/2 17-1/4
39.4 43.8
15-1/2 17-1/4
39.4 43.8
18-1/2 18-9/16
47 47.1
18-1/2 18-9/16
47 47.1
18-1/2 18-9/16
47 47.1
18-1/2 19-1/8
47 48.6
18-1/2 19-1/8
47 48.6
18-1/2 19-1/8
47 48.6
4-1/4
10.8
4-1/4
10.8
4-1/4
10.8
4
1
12
30.5
14
15-1/2 32-1/8
39.4 81.6
16-1/2 31-1/8
41.9 79.1
16-1/2 32-1/8
41.9 81.6
17-1/4 30-15/16
43.8 78.6
17-1/4 30-15/16
43.8 78.6
780 Lbs.
354 Kg
DW-720
DW-840
DW-960
DW-1080
118.1
19.7
2.5
1
Inches
CM
52-1/5
132.6
57-3/4
146.7
52-7/8
134.3
1-1/4
3.2
7-3/4
19.7
7-3/4
19.7
7-1/2
19.1
950 Lbs.
431 Kg
2.5
1
35.6
14
Inches
CM
1-1/4
3.2
950 Lbs.
431 Kg
75.2
32-3/4
83.2
139.1
58
2.5
1-1/4
3.2
1-1/4
3.2
1-1/4
3.2
1-1/4
35.6
16
Inches
CM
1-1/4
3.2
1000 Lbs.
454 Kg
147.3
58
10.2
4
40.6
16
Inches
CM
58-1/2
148.6
64-1/2
163.8
69-1/2
32-3/4
83.2
1-1/2
3.8
7-1/2
19.1
1075 Lbs.
488 Kg
DW-1210
DW-1350
DW-1480
DW-1610
DW-1810
147.3
58
10.2
4
40.6
18
Inches
CM
32-3/4
83.2
1-1/2
3.8
7-1/2
19.1
17 1/4 30-15/16 11 00 Lbs.
147.3
60-1/2
10.2
4-1/2
45.7
18
45.7
78.6
499 Kg
Inches
34
1-1/2
7-1/2
13-3/4
31
11 25 Lbs.
CM
Inches
CM
176.5
75
86.4
34
153.7
60-1/2
153.7
60-1/2
3.8
2
19.1
7-1/2
19.1
11.4
4-1/2
11.4
3.2
1-1/4
3.2
45.7
18
34.9
13-3/4
34.9
78.7
31
510 Kg
11 50 Lbs.
522 Kg
190.5
82-1/2
86.4
34
5.1
2
45.7
20
78.7
31
Inches
7-1/2
4-1/2
1-1/4
13-3/4
1250 Lbs.
CM
209.6
86.4
153.7
5.1
19.1
11.4
3.2
50.8
34.9
78.7
567 Kg
Water connections on DW-720 through DW-960: 2”
Water connections on DW-1080 through DW-1810: 2-1/2”
Revised November 2009
Page 3 of 4
AOSDG25300
Commercial Gas Boilers
SUGGESTED SPECIFICATION
The hot water supply boiler(s) shall be A. O. Smith Dura-Max® model DW ______ with an input rating of ______ BTU/hr and a recovery rating of ________________ BTU/hr at
100°F temperature rise. The boiler(s) shall be design-tested and certified to the ANSI Z21.13 standard, approved by CSA International and shall carry the ASME “H” Symbol. The wet
section shall be design-registered in accordance with the requirements of the ASME Code and shall carry an appropriate National Board Number or Canadian Registration Number.
All waterways shall be copper, brass or bronze. The heat exchanger shall be a two (2)-pass design incorporating integral-finned copper tubes. The double-row heat exchanger
shall have staggered tubes. Cast bronze return bends shall be readily removable to permit visual inspection or cleaning without removing the entire wet section assembly. Silicone
“O”-ring gaskets shall form a water-tight seal by compression and shall be isolated from the flue gases by 3/4” board-type ceramic fiber insulation. The heat exchanger assembly
shall be hydrostatically tested to a pressure of 240 psi (1655 kPa) and shall have a maximum working pressure of 160 psi (1100 kPa).The combustion chamber shall be constructed
of board-type ceramic fiber insulation rated to 2300°F (1260°C) which interlocks to form a gas-tight seal and shall be supported in a heavy-gauge corrugated steel frame. The
external cabinet shall incorporate a built-in draft hood and shall be of baked enamel steel construction. It shall be suitable for installation on combustible flooring. The burners
shall be a stainless steel stamped design and shall be mounted in a removable drawer assembly.The burner controls shall be 24 VAC and shall include slow-opening main gas valve
for soft ignition, redundant safety shutoff gas valve, main and pilot pressure regulators, recycling intermittent pilot system with one-second shutdown in the event of pilot flame
failure, automatic recycling high limit, manual reset ECO limit, main and pilot manual cocks and manual firing valve, and an ASME-rated pressure relief valve. The boiler shall be
approved by Factory Mutual (FM).The boiler shall comply with ASHRAE/IESNA 90.1-2004 standards. Optional: Factory-installed, dial-type temperature and pressure gauges shall
be mounted on the front of the cabinet.
For Technical Information and Automated Fax Service, call 800-527-1953. A.O. Smith Corporation reserves the right to make product changes or improvements without prior notice.
Revised November 2009
Page 4 of 4
AOSDG25300
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