installed my new sanyo Z5 a few days ago and was enyoing a movie today when it turned off on overheat. it was on for about an hour and a half. didnt have air con on and i didnt feel it was really hot in the room. Admittedly i wasnt doing anything but sitting in a chair. the unit is mounted upside down on a custom mounting bracket. All vent holes are clear and is mounted at least 4 feet from any walls, and 380mm from ceiling. any thoughts? also the pj was on economy mode.