Gambro AK 95 S, Service Manual

Page: 139 / 247

AK 95 / AK 95 S Service Manual
HCEN 9138 Rev. 10.2005
6:12
Calibrations
Calibration should be performed on a regular
basis to ensure optimum performance.
A complete calibration procedure consists
of the following steps:
1. Offset calibration , with a buffer solution
(a solution with a very accurate and stable
pH-value) having a pH-value in the range
of pH 6.5-7.5, followed by:
2. Slope calibration with a buffer solution
having pH-value that differs at least 2 pH-
units from the buffer used for offset cali-
bration.
Calibration schedule:
An Offset calibration should be per-
formed after one month in operation and
then every third month to verify the
performance.
A Complete calibration procedure
should be performed at installation and
then every 12 months.
Offset Calibration:
1. Make sure there is no flow or fluid in the
AK 95 S. The inlet water must be closed.
2. Start the AK 95 S, enter the Service
menu and select Calibrations .
3. Select Transducer , External and
pH TRANSDUCER from the selection
diagram.
4. Press to start calibration routine.
5. Remove the pH sensor from the pH sensor
housing by loosening the nut holding the
pH sensor and rinse the sensor in distilled
water.
6. Check that the “REF SET” on the AK 95 S
displays pH 7.
pH transducer calibration
7. Put the pH sensor in a cup with pH 7
buffer solution (ordering no. 100 810 001)
which must cover the glass membrane i.e.
the level in the cup should be at least
30mm from the bottom.
8. Stir in order to achieve balance in the
buffer solution. Do not let the pH sensor
lean against the bottom of the cup.
Wait for 2 minutes.
9.* Press to set the “REF SET” value on
the AK 95 S and wait until the calibration
display returns.
10. Press
START
UF
STOP
to load the calibration value
into the EEPROM.
11. Clean the pH-sensor in RO-water.
Remount the pH sensor into the
pH sensorhousing.