Sierra Monitor Corporation 5100-06-IT - Manual (Page 49)

Model 5100-XX-IT Toxic Gas Sensor Module
Page: 45
6. Preparation
a. Transfer the necessary electrolyte into a plastic wash bottle.
b. Confirm that system power has been removed.
c. Remove the transmitter electronics board from the main housing and unplug the sensor harness
from the transmitter electronics.
d. Unscrew the sensor assembly from the bottom of the enclosure.
e. Remove the assembly cover from the sensor assembly.
CAUTION: Only remove the sensor cover from the assembly, DO NOT attempt to unscrew the
sensor from the mounting assembly or you could damage the wiring.
7. Electrolyte Replacement (See Fig. 8-4)
a. Invert the sensor assembly so that the membrane is upward.
b. Insert the sensor assembly in a clamp, if available, and unscrew the box nut counterclockwise, and take
out the hold-down ring, membrane and O-Ring. Then pour out the old electrolyte into a beaker for
disposal.
CAUTION: Avoid contact of the electrolyte with skin, eyes and clothing. In case of contact wash
immediately - rubber gloves and safety glasses are recommended.
c. Clean the electrode with the alcohol wipes included in the electrolyte replacement kit. All oxidation
residue must be removed before re-assembly. When dirt is found inside the sensor assembly, wash the
dirt off with electrolyte.
d. Hold the sensor assembly with the sensing electrode up. Close the pressure compensation port with a
tissue. Pour approximately 10cc of fresh electrolyte from the wash bottle into the sensor, and rinse the
inside of the sensor. Empty the electrolyte into the beaker.
e. Place the O-ring on top of the washer. Then transfer one drop of electrolyte from the plastic wash bottle
to the exposed electrode surface.
f. Place a new membrane into the hold-down ring and carefully place the plastic hold-down ring on top of
the sensor body with the ring ears in the slots of the sensor body. Then fasten the sensor cover over the
assembly.
CAUTION: Never touch the membrane with your hands. Use rubber gloves or tweezers.
g. Invert the sensor so that the membrane is down. If this is the first time that electrolyte has been replace,
there should be a round Mili Seal covering the pressure compensation screw. This Mili-Seal prevented
loss of electrolyte during shipment. Remove and discard the round Mili Seal and remove the screw to
expose the electrolyte supply port.
h. Transfer electrolyte from the plastic wash bottle into the electrolyte supply port (see Fig. 8-4) until the
level is at the maximum level line on the side of the sensor body.
i. Replace the pressure compensation screw into the electrolyte supply port.
j. Replace the sensor housing cover.
k. Install the sensor assembly into the enclosure hub and tighten firmly.
l. Reconnect the sensor harness to the transmitter, carefully install the transmitter into the housing and
restore system power.
m. Recalibrate the transmitter following the instructions in Section 6.