I'm about to the point that I think it has something to do with pressure. Can't figure what would make the plugs crack like that (tiny split). The pressure relief valve is not plugged and seems to work just fine. Guess I'll ask them to put a new relief valve in it when I get back and see if that works (or put it in myself if they won't do it on warranty
. In the meantime I suppose I'll need to carry a box of plugs.......