Comfort Flow Built-in recirculation system
Navien’s patented ComfortFlow® system is the first to include a buffer tank, recirculation pump and fine-tuned controls into a tankless water heater, resolving the cold-water sandwich effect* and issues of minimal flow rates commonly found in other tankless water heaters.
* The “cold-water sandwich effect” is the undesired introduction of cold water into the hot water supply line on occasions of frequent on/off operations. (Measure Guideline : Transitioning to a Tankless Water heater, DOE, Sept.2012).