Introducing the A.O. Smith® ADAPT Premium Condensing Gas Tankless Water Heater

With X3® Scale Prevention Technology and Integrated Recirculation Pump

Delivering robust, on-demand performance, these high efficiency heaters install in practically any residential setting. The single stainless steel, heavy-duty heat exchanger design is more resilient to scale buildup and corrosion and when coupled with X3 Scale Prevention Technology, there is zero lifetime descaling maintenance required. Contact your First Supply Sales Rep. to learn more.

X3® Scale Prevention Technology

  • Extends the life of the unit up to three times longer (Compared to other tankless models without X3 Technology)
  • No warranty exclusions for hard water with X3 models
  • Maintains “like-new” performance longer
  • Easily add scale prevention to M models, kit sold separately
Unprotected tankless

Unprotected tankless:
Failed at 5.8 simulated years and 136,000 gallons

Tankless with X3 Technology

Tankless with X3 Technology:
Still running after 19.7 simulated years and 460,000 gallons


  • Integrated Recirculation Pump
  • 160k, 180k, 199k BTU/h
  • Field convertible from Natural Gas to Liquid Propane, Kit Included
  • Universal install, Indoor or Outdoor (Outdoor Vent Cap Kit Required, Kit Sold Separately)
  • 9k BTU min. input
  • 22:1 Turndown Ratio
  • 0.95 UEF (Energy Star certified)
  • Max flow rate 10.5 GPM, 0.4 GPM activation
  • Ultra-Low NOx emissions
  • 1/2" Gas Line
  • Venting Flexibility 2" up to 75' & 3" up to 150'

Adapt Premium Condensing Ultra-Low NOx 199,000 BTU Natural Gas Tankless Water Heater with X3 Scale Prevention Technology

Models with Integrated X3® Scale Prevention Technology

Item # Height Width Depth Weight
AOSATHR160X3 44.6" (113.3 cm) 16.5" (42 cm) 16.1" (41 cm) 104 lb. (47.2 kg)

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Adapt Premium Condensing Ultra-Low Nox 199,000 BTU/hr Natural Gas Tankless Water Heater

Models with Bypass Easily Add Scale Prevention Any Time*

Item # Height Width Depth Weight
AOSATHR160M 33.8" (85.9 cm) 16.5" (42 cm) 16.1" (41 cm) 104 lb. (47.2 kg)
*X3 Scale Prevention Cartridge Kit Sold Separately

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AO Smith