For a pure reference standpoint, in AC diagnostic mode, the low side reading in my '98 C280 fluctuated between 10 and 16 bars idling at operating temp. (just checked) My evap temp read 39F. The ambient temperature here in Houston is 84F.

Hope that helps and Good Luck

__________________
-Paul-
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi