A typical schedule would be to change one-third fluorescent lamps every 1500 hours to minimize lamp failure and intensity depreciation. Failing ballasts can usually be identified by burning smell and should be replaced immediatly. Ballasts can degrade after 10 years or so and may reduce lamp output. Light barriers should be kept clean. Reviewing the past 24 hours of data should be a reasonable check on sensor performance.
Unusual readings can be the sign of a faulty sensor.
Inspect all circulation fans and keep well lubricated. If erratic temperatures exist, a record of the oscillations will aide the refrigeration or electronics repair man. Sealed refrigeration units need minimal maintenance, other than keeping the coils free of dust and dirt. Water cooled units must have water pumps and other associated items inspected routinely. Steam systems have problems with solenoid valves sticking in either the on or off position.