Xylem Sentix 980 - Manual (Page 7)

SenTix Aging
17 ba75843e01 08/2009
Note
During longer storing periods, salt sediments may develop on the watering
cap. They do not affect the measuring characteristics and can easily be re-
moved with deionized water when the electrode is put into operation again.
Aging
Every pH electrode undergoes a natural aging process. With aging, the re-
sponding behavior becomes slower and the electrode slope and asymmetry
change. Moreover, extreme operating conditions can considerably shorten
the lifetime of the electrode. These are:
z
Strong acids or lyes, hydrofluoric acid, organic solvents, oils, fats, bro-
mides, sulfides, iodides, proteins
z High temperatures
z High changes in pH and temperature.
The warranty does not cover failure caused by measuring conditions and
mechanical damage.
Maintenance and cleaning
Refilling the
reference
electrolyte
During operation, a small amount of reference electrolyte leaks through the
junction from the electrode into the test sample. If the level of reference elec-
trolyte becomes too low with time, refill it through the refilling opening. Refill-
ing is very easy with the enclosed dropping bottle. Proceed as follows:
z
Cut off the tip of the dropping bottle at a right angle until the opening in the
tip can be seen
z Open the refilling opening of the electrode
z Press the tip of the dropping bottle into the refilling opening while turning
it slightly
z Pump the reference electrolyte in the shaft using the dropping bottle
z Pull the dropping bottle out of the refilling opening while turning it slightly
as necessary.