Residential Gas Tankless
Water Heaters
TANKLESS RESIDENTIAL MODELS
Fully modulating, gas fired, tankless water heater with sealed combustion
and power-vented flue. Indoor and outdoor models available for residential
applications. Supplies hot water to domestic hot water systems (directly or
indirectly) which can be used with storage tanks, recirculation systems,
hydronic heating systems, radiant floor heating systems, and/or combined
domestic & heating applications.
FEATURES
CONTINUOUS MAXIMUM FLOW RATES UP TO 6.6 GPM
ENERGY STAR® QUALIFIED
AVAILABLE IN NATURAL GAS OR PROPANE (LP)
OUTDOOR MODELS INCLUDE REMOTE CONTROL AS A STANDARD FEATURE
INDOOR MODELS INCLUDE BOTH A REMOTE CONTROL AND POWER CORD
AS STANDARD FEATURES
ATI-110-N
ATI-110-P
LOW NOx EMISSIONS
COMPLIES WITH LEAD FREE STANDARDS
SAFETY FEATURES:
■ Built in Freeze Protection
■ Manual Reset Hi Limit (Set at 194°F)
■ Overheat Cutoff Fuse
■ Inlet and Outlet Thermistors for Constant Temperature Monitoring
■ Flue Backdraft Pressure Switch
■ GFI Power Supply Connection
■ Flame Sensor
VENTING AND COMBUSTION
■ 4” Category III Stainless Steel
■ Vertical or Horizontal Installation
■ 50’ Max Length, 5 elbows max (90° elbows = 5’ equivalent length)
■ Power Vent
■ Electronic Ignition - No Pilot Light
■ 3” Combustion Air Intake (with optional kit)
OPTIONAL ACCESSORIES
■ Complete line of Stainless Steel Venting
■ Recess Box (outdoor)
■ Pipe Cover
■ Direct Vent Conversion Kit (indoor)
■ Isolation Valve Kits
ATO-110-P
ANSI Z21.10.3
CSA 4.3
WARRANTY
■ 12-year limited warranty on heat exchanger in residential applications
■ 5-year warranty on all parts
Page 1 of 2
Revised October 2012
AOSRG46815
Residential Gas Tankless
Water Heaters
TANKLESS RESIDENTIAL MODELS
GAS
CONSUMPTION
INPUT
INLET GAS
PRESSURE
DIMENSIONS
IN INCHES
INTAKE
(OPTIONAL)
HOT/
COLD/
GAS
CONN.
APPROX.
SHIPPING
WEIGHT
(LBS)
MODEL
NUMBER
FUEL
TYPE
MIN.
BTU/H
MAX.
BTU/H
ENERGY
FACTOR
(EF)
ATI-110-N
Natural
19,500
140,000
0.82
5.0
10.5
6.6
20-1/2
13-4/5
6-7/10
120
0.51
4” O.D.
3.0” O.D.
3/4” NPT
38
ATI-110-P
Propane
19,500
140,000
0.83
8.0
14.0
6.6
20-1/2
13-4/5
6-7/10
120
0.51
4” O.D.
3.0” O.D.
3/4” NPT
38
ATO-110-N
Natural
19,500
140,000
0.82
5.0
10.5
6.6
20-1/2
13-4/5
6-7/10
120
0.51
N/A
N/A
3/4” NPT
38
ATO-110-P
Propane
19,500
140,000
0.82
8.0
14.0
6.6
20-1/2
13-4/5
6-7/10
120
0.51
N/A
N/A
3/4” NPT
38
MIN.
W.C.
MAX.
W.C.
MAX
GPM**
HEIGHT
WIDTH
DEPTH
VOLT
AMP
FLUE*
All dimensions in inches.
15-150 psi water pressure. 40 psi or above recommended for maximum flow.
* Category III required
**Current numbers based on factory testing, 0.4 GPM required for continuous fire after initial ignition.
Pressure only relief valve requires (Min. 200,000 BTUs. 150 PSI). Min 50 PSI or above recommended for maximum flow.
110 Indoor/Outdoor Pressure Loss
Comparison of Flow Rates vs. Temperature Rise
7
Pressure
Loss (psi)
Head
Feet
Flow Rate (GPM)
6
5
4
3
2
1
0
0
110 INDOOR DIMENSIONS
CLEARANCES: Top 12”, Bottom 12”, Front 24”, Back 1”, Sides 2”
20
40
60
80
Temperature Rise (°F)
1-3/4" (45mm)
1-3/4" (45mm)
120
140
110 OUTDOOR DIMENSIONS
CLEARANCES: Top 36”, Bottom 12”, Front 24”, Back 1”, Sides 2”
Ø 3-9/8" (101 mm)
13-3/4" (350mm)
10" (254mm)
100
13-3/4" (350mm)
10" (254mm)
1-3/4" (45mm)
7-7/8" (203mm)
1-3/4" (45mm)
1" (26mm)
2-1/4" (56 mm) COLD
3-7/8" (98mm) GAS
4-7/8" (123mm) 120V
4-7/8" (124mm) HOT
7-3/4" (196mm)
120V 1-3/8" (36mm)
GAS 4-7/8" (124mm)
20-1/4" (520mm)
21-3/8" (544mm)
20-1/4" (520mm)
21-3/8" (544mm)
2-1/4" (57mm)
1-7/8" (47mm)
COLD 3-1/8" (79mm)
HOT 5-1/4" (133mm)
1-7/8" (47mm)
COLD 3-1/8" (79mm)
HOT 5-1/4" (133mm)
1-5/8" (43mm)
2-1/4" (56mm)
4" (102mm)
120V 1-3/8" (36mm)
GAS 4-7/8" (124mm)
1" (26mm)
2-1/4" (56 mm) COLD
3-7/8" (98mm) GAS
4-7/8" (123mm) 120V
4-7/8" (124mm) HOT
7-3/4" (196mm)
For Technical Information call 1-877-737-2840. A. O. Smith Corporation reserves the right to make product changes or improvements without prior notice.
Revised October 2012
www.hotwater.com
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AOSRG46815