Myron L ARH1 - Manual (Page 9)

D. pH Practices to Maintain Calibration.
1. Keep the sensor wet with Myron L Storage Solution.
2. Rinse away caustic solutions immediately after use.
VIII. CHANGING from CENTIGRADE to FAHRENHEIT
(Note: °F to °C is the reverse)
1. Dry Instrument THOROUGHLY.
2. Remove the 4 bottom screws and carefully open Instrument.
3. Locate dip switch labeled “TEMP COMP” on the right side of the
circuit board. Note: Factory setting is degrees “C”.
4. Set switch number 4 to the down position.
5. Carefully turn instrument over and press the key. The
displayed reading will be in Fahrenheit “°F” .
6. Replace bottom, ensuring the sealing gasket is installed in the groove
of the top half of case. Tighten screws securely. (Do NOT overtighten)
IX. CARE and MAINTENANCE
The ARH1 should be rinsed with clean water after each use. Solvents
should be avoided. Shock damage from a fall may cause instrument
failure.
A. Temperature Extremes
Solutions in excess of 160°F/71°C should not be placed in the cell cup
area; this may cause damage. The pH sensor may fracture if the ARH1
temperature is allowed to go below -10°C (14°F). Care should be
exercised not to exceed rated operating temperature. Leaving the ARH1
in a vehicle or storage shed on a hot day can easily subject the instrument
to over 150°F. This will void the warranty.
B. Battery Replacement (LO BATT)
Dry Instrument THOROUGHLY. Remove the 4 bottom screws.
Open instrument. Carefully detach battery from circuit board. Replace
with 9 volt alkaline battery. Replace bottom, ensuring the sealing gasket
is installed in the groove of the top half of case. Tighten screws evenly
and securely. (Do NOT overtighten)
C. pH Sensor Replacement
Order model RPG. When ordering, be sure to include the model and
serial number of your instrument to ensure receiving the proper type.
Complete installation instructions are provided with each replacement
sensor.
D. Cleaning Sensors
1. Conductivity or TDS
The cell cup should be kept as clean as possible. Flushing with clean
water following use will prevent buildup on electrodes. However, if very
dirty samples — particularly scaling types — are allowed to dry in the cell
cup, a film will form. This film reduces accuracy. When there are visible
films of oil, dirt, or scale in the cell cup or on the electrodes, use a foaming
non-abrasive household cleaner. Rinse out the cleaner, and your ARH1
is ready for accurate measurements.
2. pH
The unique pH sensor in your ARH1 is a nonrefillable combination type
which features a porous liquid junction. It should not be allowed to dry
out. If it does, the sensor can sometimes be rejuvenated by first cleaning
the sensor well with a liquid spray cleaner such as Windex™ or Fantastic™
and rinsing well. Do not scrub or wipe the pH sensor.
Then use one of the following methods:
1.
Pour a HOT salt solution ~60°C (140°F), preferably potassium
chloride (KCI) solution — HOT tap water with table salt (NaCl)
will work fine — in the sensor well and allow to cool. Retest.
Or
2.
Pour DI water in the sensor well and allow to stand for no more
than 4 hours (longer can deplete the reference solution and
damage the glass bulb). Retest.
If neither method is successful, sensor must be replaced.
"Drifting" can be caused by a film on the pH sensor bulb. Spray a liquid
cleaner such as Windex™ or Fantastic™ into the sensor well to clean it.
The sensor bulb is very thin and delicate. Do not scrub or wipe the pH
sensor.
Leaving high pH (alkaline) solutions in contact with the pH sensor for long
periods of time can damage it. Rinsing such liquids from the pH sensor
well and refilling well with Myron L Storage Solution, a saturated KCl
solution, pH 4 buffer, or a salty tap water, will extend the useful life.
14 15
pH