From: A. O. Smith
A.O. Smith’s ProLine XE Combination Boiler—available in three sizes—delivers immediate hot water and comfortable space heating. Its ProLine XE 540P Tankless Water Heater series integrates a recirculation pump to provide instant hot water in residential applications with dedicated recirculation lines. A simple user interface and multiple pump settings allow for the customization of pump operation to meet needs yet maximize heater efficiency.