(3) Check internal standard reading before using TDS meter as follows:
(a) Turn TDS meter upside down and note internal standard reading stamped number(1).
(b) Set range selector (1, Figure 2-17) to S.
(c) Push button (4) to right of range selector and note reading. For this check each line on the scale is 0.1. Unit is
now internally calibrated and ready to use.
(4) At times the internal standard reading may differ from the stamped number on bottom of unit. If this occurs use
the following procedures.
(a) Turn TDS meter upside down.
(b) Unsnap bottom plastic cover (5) and note position of adjusting wheel (2, Figure 2-18).
(c) Turn unit right side up. Hold TDS meter in one hand.
(d) Push button (4, Figure 2-17).
(e) Turn adjusting wheel (2, Figure 2-18) until correct internal standard reading is obtained.
Disconnect cable (3) and replace battery (4) if reading is less than internal standard at
maximum setting of the adjusting wheel.
(f) Replace bottom cover. Meter is now ready to use.
c. Adjustment of Meter Extender (Figure 2-17). When using range extender with the unit use the following
When using TDS meter without range extender no further adjustment is needed.
(1) Fill cell cup (3) halfway with product water. Fill the rest of the way with water to be tested.
(2) Set range selector (1) to 1000, push button and note meter reading.
Diluted water should be between 1000-4000 ppm
(3) Insert range extender (2) into cell cup and push down until it snaps in place.
(4) Set range selector to 100 and push button (4). Reading should be the same as previous reading.
(5) If reading is high, remove range extender and push the white end in slightly. If reading is low, push white end
out slightly. Reinstall extender. Repeat reading. Repeat Steps 1, 2, 3 and 4 as needed until the readings are the same.
d. Use of Meter.
(1) Testing without range extender:
(a) Rinse cell cup several times with water to be tested.
(b) Fill cell cup slowly until water is about 3/8 in. from top.
(c) Set range selector to 1000.
(d) Push button and read scale. If reading is less than 500 ppm, set range selector to 100 and read scale. If
reading is less than 50 ppm, set range selector to 10 and read.
If range selector is set to 1000 and meter needle travels to 5000, the RANGE
EXTENDER is required for an accurate reading.
(2) Testing with range extender:
(a) Rinse cell cup and extender several times with water to be tested.
(b) Fill cell cup slowly until water is about 3/8 in. from the top.
(c) Insert range extender and push down until it snaps in place.
(d) Set range selector to 1000.