I ask this question because anyone that has a heatmor before 1999 its got a mild steel base . So what happens
base rusts and causes base tank gasket failure and you will be leaking air and you get a crack in your tank .
and no its not the 409 stainless steels fault its base gasket leaking air making hot and cold spots and stainless will crack and slowly weep water out . So If you do have one and you think ooo its fine . just take tin off sides look behind insulation .
look at the seams between tank and base you see rust . Might want to replace that gasket . Mine looked ok only bit of rust and took tank off and ya scary ridge where gasket is all rusted out inside . Where the most rust was is where tank leaked .
look at picture
front right corner all rust orange spot is where tank has pin hole . look how close gasket and rust ridge is yep thats where pin hole is . These are my findings . goal is to let others with old heatmors know hey if I replace that gasket . It will give alot longer life . and $7000 for a new one kinda cuts in to the piggy bank .
aka project long life heatmor . After 1999 they had a stainless steel base . This leaves 6 year window for the above problem . 1994 were the first year of stainless tanks . 1999 was first year of stainless bases .
Heat550
Picture below is 1994 base installed in 1996:)
second picture is after I took sand out and cleaned off gasket surface .