sub visual : Adcanced Engineering and Technology

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ComfortFlow™ Technology

  • Eliminates minimum flow rate and activation rate requirement.
  • Eliminates "Cold water sandwich" phenomenon. (Hot/Cold/Hot stacking)
  • Quick hot water delivery

ComfortFlow technology is an advanced system designed to provide the most comfortable and seamless delivery of hot water on the market. The two key components on all "A" model condensing tankless water heaters are, internal insulated buffer tank and a recirculation pump. Since Navien is the only tankless manufacturer to provide you with these premium features you never have to worry about the "cold water sandwich" phenomenon that affects many other tankless water heaters.

Since you have a .5gal buffer tank in all "A" models you never have to worry about a cold slug in the line like other tankless manufacturers suffer from. With the included recirculation pump all "A" models are perfect for recirculation applications out of the box, there is no need to purchase extra components in most cases when installing in a recirculation application.

  • Fan
  • Dual Venturi
  • Buffer Tank
  • Negative Pressure
    Gas Valve
  • Circulation Pump
  • Display Controller
  • Premix Burner
  • Primary Stainless Steel
    Heat Exchanger
  • Secondary(Condensing)
    Stainless Steel
  • Heat Exchanger
    Water Flow Sensor
  • Condensate Collector
  • Air Pressure Sensor
  • Main PCB
  • Water Adjustment Valve

Internal water of the water heater is heated up to a certain temperature to supply hot water to the tap faster.

How Does It Work?

Secondary Heat

Heat Exchanger


Hot Water Outlet

Setting Internal Recirculation Mode

  1. Connect the water supply. (For more information, please refer to Installation Manual)
  2. Set the 2-way valve inside the water heater to "INT" (Internal Mode)
  3. Set the front panel DIP switches at the far left (set of ten ) to: 1-ON; 2-OFF.

Internal Mode

2 way valve

Dip Switch