User Guide

25
pH CALIBRATION
For best accuracy, frequent calibration of the instrument is recom-
mended. The instrument should be recalibrated for pH:
a) Whenever the pH electrode or temperature probe is replaced.
b) At least once a month.
c) After testing aggressive chemicals.
d) Whenever the battery has been replaced.
e) Where greater accuracy is required.
PREPARATION
Pour small quantities of pH 7.01 (HI 7007 or
HI 8007) and pH 4.01 (HI 7004 or HI 8004)
solution into two clean beakers.
For accurate calibration use two beakers for each buffer solution, the
first one for rinsing the tip of the electrode, the second one for
calibration. This way, contamination of the buffers is minimized.
To obtain accurate readings, use pH 7.01 (HI 7007 or HI 8007) and
pH 4.01 (HI 7004 or HI 8004) if you are going to measure acidic
samples or pH 7.01 (HI 7007 or HI 8007) and pH 10.01 (HI 7010
or HI 8010) for alkaline measurements.
If you need to calibrate HI 8014, HI 8314 and HI 8915 to NBS
standards, use pH 6.86 (HI 7006 or HI 8006) instead of pH 7.01
and pH 9.18 (HI 7009 or HI 8009) instead of pH 10.01.
PROCEDURE FOR HI 8014
• Remove the protective cap from the elec-
trode, rinse and immerse it in pH 7.01
buffer and stir gently. Wait a couple of
minutes for the reading to stabilize.
Note: the electrode should be submerged ap-
proximately 4 cm (1½") into the solution.
A ChecktempC should be located close to
the pH electrode.
• Take the temperature of the buffer solution
with a ChecktempC (or an accurate ther-
HI 7004 HI 7007HI 7004 HI 7007
H
I 7
0
0
4
HI 7007
RINSE
HI 7007
CALIBRATION
°C
HI 7007
4 cm
(1½
")
32
• If the ON/OFF key is pressed at this point, the calibration process
will end with only the offset (one-point) calibration. For best
accuracy, however, it is recommended that a two-point calibra-
tion is performed.
• The LCD will now blink "4.01 ∆". pH 10.01
can be selected by pressing the CAL key.
• Rinse with pH 4.01 (or pH 10.01) buffer
solution (2
nd
calibration point).
• Dip the electrode into a pH 4.01 (or
pH 10.01) buffer solution.
• Stir gently and wait until the stability
indicator "∆" stops flashing.
• Press CFM to confirm the second buffer
solution.
The meter is now calibrated and will return to
operational mode.
PROCEDURE FOR HI 9622
• Switch the meter on after connecting the pH electrode and the
temperature probe and the meter will display the previous
calibration date (month & day) for 3 seconds.
• Remove the protective cap from the elec-
trode, rinse the tip of the electrode with
some pH 7.01 solution, then immerse the
pH electrode and temperature probe in
the pH 7.01 buffer solution. Stir gently
and wait a couple of minutes for thermal
equilibrium.
Note: The electrode should be submerged
approximately 4 cm (1½") in the solu-
tion. The temperature probe should be
close to the pH electrode.
HI 7004
∆
CFM
CAL
month day
HI 7007
ON
OFF
4 cm
(1½
")
∆