On a vacuum insulated storage vessel a visit should cover the outer shell, neck tube and lid seating, the lid and any autofill fittings, verification of level and temperature monitoring against an independent reference, inspection of hoses, phase separators and transfer lines, confirmation that alarm outputs actually raise an alarm rather than only lighting a panel, and a recorded evaporation check where the vessel type allows one.
On a controlled rate freezer it covers chamber integrity, thermocouple condition, nitrogen solenoid and injection behaviour, and a verification run against a reference probe. Calibration should be recorded separately from the service.
