A. O. Smith ATO-520-P User Manual

Residential / Light Commercial Gas Tankless Water Heaters

TANKLESS HIGH EFFICIENCY CONDENSING OUTDOOR MODELS

FEATURES

CONDENSING TECHNOLOGY PROVIDES SIGNIFICANT ENERGY COST SAVINGS

PRIMARY HEAT EXCHANGER IS CONSTRUCTED OF HRS35 COMMERCIALGRADE COPPER

■ Stronger than standard copper and more resilient against erosion

SECONDARY HEAT EXCHANGER IS MADE OF TYPE 316L STAINLESS STEEL

■ Provides additional protection against corrosion

CONTINUOUS MAXIMUM FLOW RATES UP TO 9.0 GPM

CAN BE USED IN BOTH RESIDENTIAL AND LIGHT COMMERCIAL APPLICATIONS

ENERGY STAR®QUALIFIED

OUTDOOR MODELS INCLUDE REMOTE CONTROL AS A STANDARD FEATURE

INDOOR MODELS INCLUDE BOTH A REMOTE CONTROL AND POWER CORD AS STANDARD FEATURES

EASY-LINK UP TO 4 UNITS

■ With no additional parts or accessories needed

ELECTRONIC IGNITION-NO PILOT LIGHT

BUILT-IN DISPLAY SHOWS OPERATING TEMPERATURE ALONG WITH DIAGNOSTIC AND ERROR CODES

LOW NOx EMISSIONS

COMPLIES WITH LEAD PLUMBING LAW

SAFETY FEATURES:

■ Air-Fuel Ratio (AFR) Sensor

■ Exhaust & Water Temperature Safety Control

■ Overheat Cutoff Fuse

INTERNAL FREEZE PROTECTION SYSTEM

ACCESSORIES

■ Remote Temperature Controller

■ Pipe Cover

■ Neutralizer Kit

■ Plumbing Installation Kits

OUTDOOR MODELS

ATO-520H-N

ATO-520H-P

ANSI Z21.10.3 CSA 4.3

WARRANTY

■ 12-year limited warranty on heat exchanger in residential applications

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

■ 5-year warranty on all parts

Revised March 2012

Page 1 of 2

AOSRG46810

Residential / Light Commercial Gas Tankless Water Heaters

OUTDOOR CONDENSING MODELS

GAS CONSUMPTION INPUT INLET GAS PRESSURE

MODEL

NUMBER

FUEL TYPE

MINIMUM

BTU/H

MAXIMUM

BTU/H

MINIMUM

W.C.

MAXIMUM

W.C. HEIGHT WIDTH DEPTH

ENERGY

FACTOR

All dimension in inches. 15-150 psi Water Pressure. 40 psi or above recommended for maximum flow.

12-1/2"

1/2" (12.5mm)

GAS 6" (153.6mm)

HOT 7-1/4" (182.1mm)

120VAC 8-1/2" (216.3mm)

COLD 8-5/8" (220.6mm)

10-1/2" (266.8mm)

Condensate drain port

(316mm)

25-1/2" (649mm)

4-1/2" (115mm)

120VAC 2-1/4" (58.2mm)

0.91

HOT/COLD

GAS CONN.

18-1/2" (470mm)

12-1/2" (320mm)

DIMENSIONS IN INCHES

25-3/5

18-1/2

3-1/2" (90mm)

4-1/2" (115mm)

1-1/4" (29.2mm) COLD

4-5/8" (116.8mm) GAS

6-1/4" (159.1mm)HOT 5-5/8" (142.2mm)

Condensate drain port

APPROX.

SHIPPING

WEIGHT

(LBS)

12-2/5

29-1/2" (751mm)

CLEARANCES: Top: 36”; Bottom: 12”; Front: 24”; Back: .05”; Sides: 3”

Flow Rate vs. Temperature Rise

10.0

9.0

8.0

7.0

6.0

5.0

4.0

3.0

Flow Rate (gpm)

2.0

1.0

0.0

0 20 40 60 80 100 120

Temperature Rise (°F)

140

Pressure Loss

Pressure Loss (psi)

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0

Flow Rate (gpm)

120

100

Head Feet

Set Temperature : 125°F & lower

Set Temperature: 130

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 March 2012 Page 2 of 2

F & Higher

www.hotwater.com AOSRG46810