Replacement tube sheet coil (heat exchanger) assembly for Sta-Rite Max-E-Therm HD heaters, models 300/333 and 400 manufactured after Jan 12, 2009 (Pentair 474064). It circulates water through cupro-nickel tubes to transfer heat and resist corrosion in salt or aggressive water. The OEM assembly matches the post-2009 “new tub” design-verify your heater’s manufacture date before ordering.








