A.O. Smith ATI-110U 200, ATI-310U 200, ATI-510U 200+, ATO-110U 200, ATO-310U 200 User Manual

COMMERCIAL-GRADE

RESIDENTIAL / COMMERCIAL GAS WATER HEATERS

ULTRA LOW-NOx NON-CONDENSING
TANKLESS WATER HEATERS

COMMERCIAL-GRADE RESIDENTIAL / COMMERCIAL

Fully modulating, gas fired, tankless water heater with sealed combustion and power
vented flue. Indoor and outdoor models available for residential and commercial
applications. Supplies hot water to domestic hot water systems and can be used
with water storage tanks, recirculation systems, and/or combined domestic & heating
applications.

FEATURES:
FIELD CONVERTIBLE FROM

NATURAL GAS TO PROPANE

COMPLIES WITH SCAQMD RULE

1146.2 AND OTHER AIR QUALITY
MANAGEMENT DISTRICTS
WITH SIMILAR NOx EMISSION
REQUIREMENTS OF 14 ng/J
OR 20 PPM

MAXIMUM FLOW RATES UP TO

10.0 GPM

COPPER HEAT EXCHANGER

• 25x better heat transfer than stainless steel thus
stabilizing outgoing water temperature quicker
and reducing pressure drop across the heat
exchanger

INDOOR AND OUTDOOR MODELS
AVAILABLE

SAFETY FEATURES:

• Built-in Freeze Protection

• Manual Reset Hi Limit (Up to 194°F)

• Overheat Cutoff Fuse

• Inlet and Outlet Thermistors for Constant
Temperature Monitoring

• Air Fuel Ratio Rod

• Flame Sensor

VENTING AND COMBUSTION

• 4” Category III Stainless Steel

• 3” Combustion Air Intake

• 60’ Max Length, 6 Elbows max
(90° elbows = 5’ equivalent length)

• Power Vent or Power Direct Vent

• Vertical or Horizontal Installation

• Electronic Ignition - No Pilot Light

INDOOR MODELS

ATI-110U, ATI-310U, ATI-510U

OUTDOOR MODELS

ATO-110U, ATO-310U, ATO-510U

OUTDOOR MODELS INCLUDE
REMOTE CONTROL AS A STANDARD
FEATURE

INDOOR MODELS INCLUDE A BUILT­IN TEMPERATURE CONTROLLER AND
A FACTORY-INSTALLED POWER CORD
AS STANDARD FEATURES

ATI-510U AND ATO-510U CAN BE
USED IN BOTH RESIDENTIAL AND
COMMERCIAL APPLICATIONS

• Easy-Link up to 4 units (no additional parts or
accessories needed)

• Multi-link up to 20 units

COMPLIES WITH LEAD FREE

OPTIONAL ACCESSORIES

• Complete Line of Stainless Steel Venting

• Recess Box (outdoor models)

• Pipe Cover

• Isolation Valve Kit

• Backflow Preventer

• Concentric Termination Kits

WARRANTY

• 15-year limited warranty on heat exchanger in
residential applications

• 5-year limited warranty on heat exchanger in
commercial applications

• 5-year limited warranty on all parts

STANDARDS

(510U models only)

© June 2017 A. O. Smith Corporation. All Rights Reserved

www.hotwater.com | 800-527-1953 Toll-Free USA | A. O. Smith Corporation | 500 Tennessee Waltz Parkway | Ashland City, TN 37015

ANSI Z21.10.3

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AOSBG45100

120 VAC 1-5/8" (40 mm)
COLD 1-5/8" (41 mm)
GAS 5" (127 mm)

HOT 4-5/8" (116 mm)

20-1/2" (520 mm)

1" (26 mm)

13-3/4" (350 mm)

10" (254 mm)

1-3/4" (45 mm) 1-3/4" (45 mm)

21-1/2" (545 mm)

1-3/8" (36 mm)

4-3/8" (113mm)

19-3/8" (493 mm)

120 VAC 3" (75 mm)
GAS 5-1/4" (135 mm)

HOT 6" (153 mm)

COLD 6" (153 mm)

2-1/4" (58 mm)

3-5/8"(93 mm)

10" (256 mm)

1-7/8" (47 mm)

120 VAC 1-5/8" (40 mm)
COLD 1-5/8" (41 mm)
GAS 5" (127 mm)

HOT 4-5/8" (116 mm)

20-1/2" (520 mm)

1" (26 mm)

13-3/4" (350 mm)

10" (254 mm)

1-3/4" (45 mm) 1-3/4" (45 mm)

21-1/2" (545 mm)

1-3/8" (36 mm)

4-3/8" (113mm)

19-3/8" (493 mm)

120 VAC 3" (75 mm)
GAS 5-1/4" (135 mm)

HOT 6" (153 mm)

COLD 6" (153 mm)

2-1/4" (58 mm)

3-5/8"(93 mm)

10" (256 mm)

1-7/8" (47 mm)

120VAC 1-7/8" (49 mm)

GAS 4-1/4" (109 mm)

COLD 5" (127 mm)

120 VAC 1-5/8" (40 mm)
COLD 1-5/8" (41 mm)

GAS 5" (127 mm)

HOT 4-5/8" (116 mm)

1" (26 mm)

13-3/4" (350 mm)

10" (254 mm)

1-3/4" (45 mm) 1-3/4" (45 mm)

21-1/2" (545 mm)

19-3/8" (493 mm)

120 VAC 3" (75 mm)
GAS 5-1/4" (135 mm)

HOT 6" (153 mm)

COLD 6" (153 mm)

9-1/2" (241 mm)

8" (203 mm)

1-5/8" (43 mm)

120 VAC 1-5/8" (40 mm)
COLD 1-5/8" (41 mm)

GAS 5" (127 mm)

HOT 4-5/8" (116 mm)

1" (26 mm)

13-3/4" (350 mm)

10" (254 mm)

1-3/4" (45 mm) 1-3/4" (45 mm)

21-1/2" (545 mm)

19-3/8" (493 mm)

120 VAC 3" (75 mm)
GAS 5-1/4" (135 mm)

HOT 6" (153 mm)

COLD 6" (153 mm)

9-1/2" (241 mm)

120VAC 1-7/8" (49 mm)

GAS 4-1/4" (109 mm)

COLD 5" (127 mm)

8" (203 mm)

1-5/8" (43 mm)

COMMERCIAL-GRADE

RESIDENTIAL / COMMERCIAL GAS WATER HEATERS

Model Number Type*

Gas Consumption Input Inlet Gas Pressure**

Minimum

BTU/H

Maximum

BTU/H

Minimum

in. W.C.

Maximum

in. W.C.

UEF

Maximum

GPM***

Hot/Cold

Connections

Gas

Connection

Dimensions in Inches

Height Width Depth

Weight (lbs)

Indoor Models

ATI-110U 200 Natural 15,000 140,000 4.0 10.5 0.81 6.6 3/4" NPT 3/4" NPT 20-1/2 13-3/4 10 39
ATI-310U 200 Natural 15,000 190,000 4.0 10.5 0.82 8 3/4" NPT 3/4" NPT 20-1/2 13-3/4 10 39
ATI-510U 200+ Natural 15,000 199,000 4.0 10.5 0.82 10 3/4" NPT 3/4" NPT 20-1/2 13-3/4 10 40

Outdoor Models

ATO-110U 200 Natural 15,000 140,000 4.0 10.5 0.81 6.6 3/4" NPT 3/4" NPT 20-1/2 13-3/4 9-1/2 39
ATO-310U 200 Natural 15,000 190,000 4.0 10.5 0.82 8 3/4" NPT 3/4" NPT 20-1/2 13-3/4 9-1/2 39
ATO-510U 200+ Natural 15,000 199,000 4.0 10.5 0.81 10 3/4" NPT 3/4" NPT 20-1/2 13-3/4 9-1/2 40

15-150 PSI water pressure. 40 PSI or above recommended for maximum flow.
*Field gas convertible from natural gas to propane. Conversion kit is included with the heater.
**For Propane, minimum inlet gas pressure is 8.0 in W.C. and maximum inlet gas pressure is 14.0 in W.C.
***Current numbers based on factory testing; 0.5 GPM required for activation; 0.4 GPM required for continuous fire after initial ignition.
+Suitable for commercial applications.
Indoor models are certified from sea level to 10,100 ft. elevations. Outdoor models are certified from sea level to 6,000 ft. elevation.

INDOOR MODEL DIMENSIONS

CLEARANCES: TOP 12”, BOTTOM 12”, FRONT 4”, BACK 1”, SIDES 3”

FRONT VIEW FRONT VIEW

SIDE VIEW SIDE VIEW

CLEARANCES: TOP 36”, BOTTOM 12”, FRONT 24”, BACK 1”, SIDES 3”

OUTDOOR MODEL DIMENSIONS

Approx

Shipping

BOTTOM VIEW BOTTOM VIEWTOP VIEW TOP VIEW

HOT 5"(127mm)

13-1/8" (334 mm)

5-1/8" (130 mm)

4-3/8" (113 mm)

13-1/8" (334 mm)

HOT 5" (127 mm)

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AOSBG45100