my contractor just installed one during remodel of master bath....now, every 6 minutes or so, its like the thing makes the "waterfilling tank" sound for only a few seconds....then it happens again 6 minutes later quite annoying for a 400 $ commode...anyway, all the flushing mechansims were in the tank when it delivered whats the problem here?? Ive "poked around" in the tank but nothing helps !!