RKI Instruments GX-3R User Manual

82 • Chapter 6: Maintenance GX-3R Operator’s Manual
5 . Install the new buzzer cover between the AIR and POWER MODE buttons as shown
below.
6 . Reinstall the rubber boot.
Replacing the Sensor Filters
CAUTION: The buzzer cover, sensors, and filters are the only user-serviceable parts in the
GX-3R. Do not replace or modify any other part.
Combustible Gas Sensor Filter
: The H
2
S filter disk is dark red in color and although it may
darken over time, its color is not indicative of remaining filter life. The H
2
S filter disk can
absorb H
2
S for 33 ppm hours and should be replaced after that much exposure. With this
many ppm hours of absorption, the H
2
S filter disk should be replaced after 80 minutes of
exposure to 25 ppm H
2
S. This equates to replacing the H
2
S filter disk after 40 2-minute
calibrations with a cylinder containing 25 ppm H
2
S. If H
2
S exists in the monitoring
environment, the H
2
S filter disk will have to be replaced more frequently.
Dual CO/H
2
S Sensor Filter: The dual CO/H
2
S sensor has a half black/half white filter
installed over it. The filter should be replaced if you notice either 1) unexplained CO readings
or 2) For users with a 1 ppm H
2
S alarm setpoint: a drift on the H
2
S channel’s zero reading,
unexplained H
2
S readings, the filter appears dirty, or every 6 months (whichever is sooner).
CO-Only Sensor Filter: A black charcoal filter is installed over CO-only sensors. The filter
should be replaced if you notice unexplained CO readings.
H
2
S-Only Sensor Filter: A white humidity filter is installed over H
2
S-only sensors. The filter
absorbs humidity in the sampling environment to prevent unstable readings around 0 ppm
H
2
S. For users with a 1 ppm H
2
S alarm setpoint, the filter should be replaced if you notice: a
drift on the H
2
S channel’s zero reading, unexplained H
2
S readings, the filter appears dirty, or
every 6 months (whichever is sooner). For users with a 2 ppm or higher H
2
S alarm setpoint,
the filter does not necessarily ever need to be replaced.
1 . Verify that the GX-3R is off.
2 . Turn the GX-3R upside down.
3 . Use a small Phillips screwdriver to unscrew the two screws holding the bottom cover to
the rest of the GX-3R’s case. Only unscrew them until the heads are flush with the edge
of the bottom cover.
Figure 11: Buzzer Cover Replacement

RKI Instruments GX-3R Specifications

General

Brand	RKI Instruments
Model	GX-3R
Category	Measuring Instruments
Language	English