wtw Multi 3430, Operating Manual

Page: 90 / 102

What to do if... Multi 3430
90 ba75865e02 12/2009
6.2 pH
Error message
OFL, UFL
Error message,
Error
Cause Remedy
IDS pH sensor:
– Measured value outside the
measuring range
– Use suitable IDS pH sensor
– Air bubble in front of the dia-
phragm
– Remove air bubble
– Air in the diaphragm – Extract air or moisten dia-
phragm
– Cable broken – Exchange IDS pH sensor
– Gel electrolyte dried out – Exchange IDS pH sensor
Cause Remedy
IDS pH sensor:
– The values determined for zero
point and slope of the IDS pH
sensor are outside the allowed
limits.
– Recalibrate
– Junction contaminated – Clean the junction
– IDS pH sensor broken – Exchange IDS pH sensor
– Buffer solutions:
– Wrong buffer solutions – Change calibration proce-
dure
– Buffer solutions too old – Use only once.
Note the shelf life
– Buffer solutions depleted – Change solutions