AO Smith ATI-540H-N Indoor NG Ultra-Low NOx Condensing Tankless


Weight: 63.00 lbs

Rush Order:

199,000 BTU tankless gas water heater with Ultra-Low NOx emissions
Easy, inexpensive venting with PVC


• Primary heat exchanger is constructed of HRS35, a commercial grade of copper that is more resistant to corrosion
• Integrated temperature controls
• Advanced diagnostics to simplify troubleshooting
• Easily convertible from natural gas to liquid propane (LPG) with supplied kit
• Maximum flow rate of 10.0 GPM
(See temperature rise table in spec sheet for temperature output level at 10.0 GPM. Hot water at that flow rate depends on incoming water temperature.)
• Output temperature adjustable from 100°F to 185°F
(See temperature rise table in spec sheet for flow rates at various output temperature settings. Output temperature depends on incoming water temperature and flow rate.)
• ENERGY STAR qualified
• Energy factor of 0.95
• Meets Ultra-Low NOx emission requirements
• 15-year limited warranty on heat exchanger in residences (10 years in commercial locations). 5-year warranty on parts.
• Built in freeze, overheat, and surge protection system


NSF certified


Emissions Ultra-Low NOx
California Energy Commission Registered Yes
Maximum BTUs 199,000
Minimum BTUs (natural gas model) 15,000
Limited Heat Exchanger Warranty 15 Years
Limited Parts Warranty 5 Years
Water Connection Location Bottom
Water Connection Size 3/4"
Heat Exchanger HRS35 Copper Alloy
Secondary Heat Exchanger Stainless Steel
Voltage 120
Energy Factor 0.95
Remote Control Included
Technology Condensing
Maximum Output Temperature Setting 160°F **
Height 23.625"
Width 17.75"
Depth 11.25"
Product Weight 59 lbs/27 kg
Shipping Weight 63 lbs

** This is the maximum output temperature, not a minimum, and depending on the water flow rate and incoming water temperature, the actual output temperature may not reach 160°F.


Spec Sheet

This model is 100% identical to the American GT-540-NIH. The only difference is the label.

The GT-540-NIH can be set to a maximum output temperature of 160 degrees F. Note that this is a maximum, not a minimum. The actual output temperature depends on the water flow rate and incoming water temperature.

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Aug 23, 2016
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