The new NPE-2 series condensing tankless water heaters from Navien have industry-leading features such as 2" PVC venting up to 75', TDR up to 15:1, and EZNav multiline control panel with setup wizard, while continuing to offer dual stainless steel heat exchangers and patented ComfortFlow recirculation technology (NPE-A2), Navien states. Navieninc.com