If they are going to be pedantic about it, fit a recorder device to it;
rather than the old graph types you can get electronic ones that will hold a
whole month's worth, and the upmarket one can even be wired into your
automatic phone system to call someone in if the equipment goes outside set
performance limits. I know some labs that have these fitted to their
processors (Just like the fridge in Blood Bank) so that if there is a drop
in temp. (usually a power out) whoever is oncall gets an electronic
recording identifying the equipment and comes in to save the run (or is it
save the day, the next day's work?).
There are firms that specialise in this sort of monitoring as well including
some security firms eg. Wormald or Chubb.
regards Mike Rentsch (Downunder)