Product Manual

3
contact with reservoir bottom, then turn the cap 1/4 turn. Do NOT over
tighten, this can damage the IRROMETER gauge or stopper.
50
Remove the plastic tip cover on the instrument, or 0remove
from the bucket of sand, and install the IRROMETER in the
prepared hole.
See section “INSTALLATION” page 6.
60
Pump the IRROMETER as illustrated each day for 3 to 6 days
or until no further air bubbles appear. Tapping the side of the
instrument with cap assembly will facilitate air release. Refill the
reservoir as necessary and replace filler cap. A well de-aired
instrument increases sensitivity and reduces water use in
maintaining reading.
NOTE: Small champagne type bubbles of air which appear
during de-airing are not of concern.
If de-airing is more conveniently accomplished before installation,
place the instruments in a large plastic container half filled with water
and follow the above steps. Be sure to protect the tip from air drying
when transporting IRROMETERS to installation site.
See Note 2.
CAUTION for LT & MLT — with models “LT” and “MLT” carefully pull
a vacuum to a reading of 30 to 35 on the gauge and be careful to
bleed vacuum slowly. These gauges are very sensitive and can be
damaged by a rapid release of vacuum or over-pumping. The MLT
uses a syringe style vacuum pump, refer to supplemental instructions.
See picture.
MODEL “MLT” FILL & AIR REMOVAL INSTRUCTIONS — 1.
Remove cap, tip protector and plastic bag covering tip. 2. Place tip in
clean water and soak overnight – you do
NOT need to fill the instrument. Step 5
below will complete the filling process. 3.
Make IRROMETER field solution by
adding one drop of IRROMETER fluid to a
cup of clean water. 4. Fill syringe half full
with IRROMETER field solution. 5. To fill,
place syringe tip loosely in O-ring seal
(located in cap opening), depress syringe
plunger to squirt water into the body tube of
the MLT. Do not seat the syringe to the O-
ring in this step as it could force the gauge
needle against the stop. (RSU units do
NOT have a gauge needle). 6. To remove
air, place syringe tip in O-ring seal (located
in cap opening), press in firmly to make a seal. W
ith instrument at 45
angle (gauge or RSU down or on the underside), PULL GENTLY on
syringe to create a partial vacuum on the gauge or RSU (on gauge
model, do NOT exceed full scale of gauge or 40 kPa/CB) and release
slowly. Pumping this way several times will get most of the air out of
the gauge or RSU. 7. Remove syringe by slowly twisting while pulling
out to avoid a rapid release of vacuum, fill instrument cap opening
with water. 8. Replace cap – tighten until gauge needle moves toward
De-airing in the Ground
De-airing Instrument
De-airing MLT
Filling ML
T