When asking for technical help at the very least let us know the version of firmware you are running.Cliff's Calibration (Mapping) Guide is a MUST READ: http://www.vemssupport.com/forum/index.php/topic,97.0.html
this is just a shot in the dark, but is it possible that the measurement scale is off by .1? for example 40 degrees could be 1,620? what temp do you get on the screen?