Tankless Water Heater Non-Condensing Concentric Vent Indoor 190,000 BTU Natural Gas/Propane

Fully modulating, gas fired, tankless water heater with sealed combustion and power vented flue. Supplies hot water to domestic hot water systems (directly or indirectly) and can be used with water storage tanks, re-circulation systems, and/or combined domestic and heating applications.

The ATI-310C-N tankless water heater uses up to 190,000 BTUs of Natural Gas or Liquid Propane to deliver a max flow rate of 8.0 GPM. It utilizes condensing technology to achieve a Uniform Energy Factor of 0.82. This model meets Ultra-Low NOx requirements, and has a 15-year limited warranty on the heat exchanger in residential applications.


  • Field Convertible From Natural Gas to Propane
  • Easily convertible from natural gas to propane with supplied kit.
  • Copper Heat Exchanger
  • 25x better heat transfer than stainless steel thus stabilizing outgoing water temperature quicker and reducing pressure drop across the heat exchanger.
  • Safety Features
  • Built-in Freeze Protection, Manual Reset Hi Limit, Overheat Cutoff Fuse, Inlet and Outlet Thermistors for Constant Temperature Monitoring.
  • Venting and Combustion
  • Direct vent APNC35 concentric vent system, Vertical or Horizontal Vent Termination Installation, Power Direct Vent, Electronic Ignition- No Pilot Light.
  • Tech Specs
  • Emissions: Ultra-Low NOx
  • Maximum BTUs: 190,000
  • Minimum BTUs: 15,000
  • UEF: 0.82
  • Limited Heat Exchanger Warranty: 15 Years
  • Limited Parts Warranty: 5 Years
  • Water Connection Location: Bottom
  • Water Connection Size: 3/4"
  • Heat Exchanger: Copper
  • Voltage: 120
  • Digital Display: Yes
  • Technology: Non-Condensing
  • Dimensions & Venting
  • Type: Space Saving
  • Height: 20 1/2"
  • Width: 13 3/4"
  • Depth: 10 1/2"
  • Product Weight: 51lbs/23.1kg
  • Shipping Weight: 55
  • Vent Type: Concentric Vent