Xylem FDO 925 - Manual (Page 9)

FDO
®
925 Maintenance, cleaning, replacement
25 ba75898s01 04/2010
3 Maintenance, cleaning, replacement
3.1 General maintenance instructions
Handling of the
sensor cap
Despite its exterior robustness, the sensor is an optical high precision instru-
ment. Therefore, special care should be taken when doing any maintenance
or cleaning work:
z Dirt and moisture under the sensor cap can affect the functioning and
shorten the service life of the sensor cap. Therefore, make sure the work-
ing environment is clean and dry prior to removing the sensor cap.
z Please do not touch the outer sensor membrane with your fingers. Touch
the sensor cap at the sides only (arrows in figure on the left).
z Avoid any great mechanical stress of the sensor membrane (pressure,
scratches).
z Exposure to light, particularly daylight, of the interior of the sensor cap will,
by-and-by affect the measurement characteristics and shorten the service
life of the sensor cap. Therefore, the interior of the sensor cap should not
be exposed to direct sunlight. Avoid any exposure to light that exceeds the
extent required for necessary maintenance and cleaning activities. Store
dismantled sensor caps in a light-protected environment only.