RKI Instruments GX-82 - Manual (Page 16)

12 • Maintenance Model GX-82 Instruction Manual
Maintenance
Batteries
1. Check the battery voltage periodically by pressing the BATT button. Replace the
batteries before the voltage drops to the operational limit (see “Alarms” on page 7).
WARNING: Take the GX-82 to a non-hazardous location before replacing the batteries.
2. To replace the batteries, slide the battery compartment cover off the instrument case.
Remove the batteries and verify that the battery compartment and electrical contacts
are clean. If necessary, use a soft wire brush to gently clean the compartment and
contacts. Insert fresh batteries (alkaline or fully charged Ni-Cd) according to the
polarity (+/-) marking, then replace the cover.
3. Bias Current Discharge
The batteries continuously supply a small current to maintain the H
2
S and CO
sensors, even when the GX-82 is off (see Sensor Maintenance). This current drain is
minimal but will result in a normal discharge of the batteries over a period of several
weeks.
NOTE: If the batteries are fully discharged before replacement, allow up to 1/2 hour for
the H
2
S and CO circuits to show a normal response.
CO Filter
CO sensors are equipped with an activated carbon filter that removes H
2
S and most
hydrocarbons to limit interference with the CO measurement.
To install the filter, slip it over the face of the CO sensor. Make sure the filter fits snugly
and is seated properly. Replace the filter when CO readings become suspect (for example,
the CO circuit calibrates properly but shows response in a known CO-free environment).
Sensor Maintenance
Electrochemical sensors (O
2
, H
2
S, CO) gradually deteriorate, regardless of use, and
require periodic replacement. Combustibles sensor life is generally related to usage, but
certain environmental factors may affect duration.
The GX-82 sensors are easy to replace, but only the combustibles sensor contains user-
serviceable components. If a sensor requires replacement, call RKI or your local
distributor. All sensors are warranted usable for one year from the date of shipment.
Sensors that fail within the warranty period will be replaced at no charge.
Combustibles sensor
Replace the combustibles sensor or filaments when:
• the combustibles circuit cannot be calibrated correctly
• the COMB (%LEL) display does not show 0 immediately after the start-up sequence,
and cannot be set to zero by the Auto Zero command