Myron L TH1 - Manual (Page 16)

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2. Reloading Factory Calibration (Cond or TDS)
If calibration is suspect or known to be incorrect, and no standard solution
is available, the calibration value can be replaced with the original factory
value for that solution. This “FAC” value is the same for all TechPro IIs,
and returns you to a known state without solution in the cell. The “FAC”
internal electronics calibration (which bypasses the electrodes and cell) is
not intended to replace calibration with conductivity standard solutions. If
another solution type requires resetting, change solution type and repeat
this procedure.
a. Press or .
b. Press .
c. Press key until “FAC” appears and release.
d. Press to accept the factory calibration setting.
3. pH Calibration (TPH1 & TH1)
Important: Always “zero” your TechPro II with a pH 7 buffer solution
before adjusting the gain with acid or base buffers, i.e., 4 and/or 10.
a. pH Zero Calibration (TPH1 & TH1)
1. Rinse sensor well 3 times with 7 buffer solution.
2. Refill both sensor wells with 7 buffer solution.
3. Press to verify the pH
calibration. If the display
shows 7.00, skip the pH Zero
Calibration and proceed to
section b. pH Gain Calibration.
4. Press to enter calibration
mode. The “CAL”, “BUFFER” and “7” annunciators will appear
(see Figure 3). Displayed value will be the uncalibrated sensor.
NOTES: If a wrong buffer is added (outside of 6-8 pH), “7” and “BUFFER”
Figure 3
BUFFER
pH
CAL