If the temp limits aren't in your FCOM, you should ask the manufacturer. IIRC, operating temps for TSO'd Arinc 700 avionics is -20 to +70 C. . EFIS is not TSO'd, however, but depends on TSO'd inputs.
Solid state components in avionics units are often operated very cold, to shake out the weak ones.
CRT EFIS generate quite a bit of heat, as does the backlighting on LCD EFIS, but cold starts should be avoided where practical. We used to cold soak intermittent avionics LRUs (Line Replaceable Units) in the shop, and then operate them as they thawed. Sometimes they would go wacky when passing through 32F, as ice inside them turned to dew. It would help to keep the humidity low on the fright deck and in the avionics compartment.
It would also be helpful to know what kind and age of fleet you have.
GB
Last edited by Graybeard; 5th Mar 2009 at 12:49.
Reason: Clarification