RKI Instruments GX-2012 User manual

www.rkiinstruments.com
GX-2012
Operator’s Manual
Part Number: 71-0335
Revision: C
Released: 7/23/15

GX-2012 Operator’s Manual
WARNING
Read and understand this instruction manual
before operating instrument. Improper use of the
gas monitor could result in bodily harm or death.
Periodic calibration and maintenance of the gas
monitor is essential for proper operation and
correct readings. Please calibrate and maintain
this instrument regularly! Frequency of
calibration depends upon the type of use you
have and the sensor types. Typical calibration
frequencies for most applications are between 1
and 3 months, but can be required more often or
less often based on your usage.

Warranty GX-2012 Operator’s Manual
Warranty
RKI Instruments, Inc. warrants the GX-2012 sold by us to be free from
defects in materials, workmanship, and performance for a period of two years
from the date of shipment from RKI Instruments, Inc. This includes the
instrument and the original sensors. Replacement parts are warranted for 1
year from the date of their shipment from RKI Instruments, Inc. except for
replacement sensors which are warranted for 2 years. Any parts found
defective within their warranty period will be repaired or replaced, at our
option, free of charge. This warranty does not apply to those items which by
their nature are subject to deterioration or consumption in normal service,
and which must be cleaned, repaired, or replaced on a routine basis.
Examples of such items are:
Warranty is voided by abuse including mechanical damage, alteration, rough
handling, or repair procedures not in accordance with the instruction manual.
This warranty indicates the full extent of our liability, and we are not
responsible for removal or replacement costs, local repair costs,
transportation costs, or contingent expenses incurred without our prior
approval.
THIS WARRANTY IS EXPRESSLY IN LIEU OF ANY AND ALL OTHER WARRANTIES
AND REPRESENTATIONS, EXPRESSED OR IMPLIED, AND ALL OTHER OBLIGATIONS
OR LIABILITIES ON THE PART OF RKI INSTRUMENTS, INC. INCLUDING BUT NOT
LIMITED TO THE WARRANTY OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE. INNO EVENT SHALL RKI INSTRUMENTS, INC. BE LIABLE
FOR INDIRECT, INCIDENTAL, OR CONSEQUENTIAL LOSS OR DAMAGE OF ANY KIND
CONNECTED WITH THE USE OF ITS PRODUCTS OR FAILURE OF ITS PRODUCTS TO
FUNCTION OR OPERATE PROPERLY.
This warranty covers instruments and parts sold to users only by authorized
distributors, dealers, and representatives as appointed by RKI Instruments,
Inc.
We do not assume indemnification for any accident or damage caused by the
operation of this gas monitor and our warranty is limited to replacement of
parts or our complete goods.
Absorbent cartridges
Filter elements, disks, or sheets
Pump diaphragms and valves

GX-2012 Operator’s Manual Table of Contents
Table of Contents
Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
About the GX-2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
About This Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Chapter 2: Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Instrument Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
LCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Control Buttons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Printed Circuit Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Alarm LED Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Infrared Communications Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Buzzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Vibrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Batteries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Flow Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Sensors and Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Inlet Filter Holder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Standard Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Tapered Rubber Nozzle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Belt Clip. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Wrist Strap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Sample Hose & 10 Inch Probe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Charging Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Optional Probes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Purge Tee Fitting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
External Dilution Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Table of Contents GX-2012 Operator’s Manual
Chapter 3: Using the GX-2012 in Normal Mode . . . . . . . . . . . . . 19
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Start Up, Normal Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Turning On the GX-2012, Normal Mode Only . . . . . . . . . . . . . . . . 19
Turning On the GX-2012 in Normal With All Modes Active . . . . . 25
Performing a Fresh Air Adjustment, Normal Mode. . . . . . . . . . . . . 27
Turning Off the GX-2012, Normal Mode. . . . . . . . . . . . . . . . . . . . . 28
Measuring Mode, Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Monitoring an Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Using Optional Probes and Fittings . . . . . . . . . . . . . . . . . . . . . . . . . 29
Combustible Gas Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Snap Log Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Measuring Mode, Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Resetting and Silencing Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Responding to Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Inert Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Start Up and Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Display Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
HC Range Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Peak Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
STEL Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
TWA Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Alarm Points Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Operation Time Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Date/Time Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Remaining Log Time Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Clear Data Logger Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Pump Off Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
User ID Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Station ID Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Snap Logging Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Peak Bar Select Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Datalogging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
SDM-2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Calibration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Calibration/Bump Test Supplies and Equipment . . . . . . . . . . . . . . . 57

GX-2012 Operator’s Manual Table of Contents
Preparing for Calibration or Bump Test . . . . . . . . . . . . . . . . . . . . . . 58
Calibrating the GX-2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Bump Testing the GX-2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Chapter 4: Using the GX-2012 in Bar Hole Mode . . . . . . . . . . . . 72
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Start Up, Bar Hole Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Turning On the GX-2012, Bar Hole Mode . . . . . . . . . . . . . . . . . . . . 72
Performing a Fresh Air Adjustment, Bar Hole Mode. . . . . . . . . . . . 78
Bar Hole Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Performing a Bar Hole Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Turning Off the GX-2012, Bar Hole Mode . . . . . . . . . . . . . . . . . . . . 82
Chapter 5: Using the GX-2012 in Leak Check Mode . . . . . . . . . 83
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Start Up, Leak Check Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Turning on the GX-2012, Leak Check Mode. . . . . . . . . . . . . . . . . . . 83
Performing a Fresh Air Adjustment, Leak Check Mode . . . . . . . . . . 89
Leak Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Setting the Display Range Value. . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Locating a Leak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Overscale Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Turning the Alarm On and Off in Leak Check Mode . . . . . . . . . . . . 92
Peak Hold Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Snap Log Mode, Leak Check Mode Operation. . . . . . . . . . . . . . . . . . 93
Viewing Snap Log Data in Leak Check Mode Operation . . . . . . . . . 96
Turning Off the GX-2012, Leak Check Mode . . . . . . . . . . . . . . . . . . 99
Chapter 6: Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Tips for Using Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Using Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Updating the Date and Time Settings. . . . . . . . . . . . . . . . . . . . . . . 103
Performing a Fresh Air Adjustment . . . . . . . . . . . . . . . . . . . . . . . . 103
Calibrating Using Auto Calibration . . . . . . . . . . . . . . . . . . . . . . . . 105
Calibration Using Single Calibration . . . . . . . . . . . . . . . . . . . . . . . 108
Performing a Bump Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Turning the Lunch Break Setting On or Off. . . . . . . . . . . . . . . . . . 116

Table of Contents GX-2012 Operator’s Manual
Updating the Alarm Latching Settings. . . . . . . . . . . . . . . . . . . . . . 117
Updating the Alarm Silence Settings . . . . . . . . . . . . . . . . . . . . . . . 118
Updating the Data Logging Interval. . . . . . . . . . . . . . . . . . . . . . . . 119
Updating the Alarm Point Settings . . . . . . . . . . . . . . . . . . . . . . . . 120
Turning the Clear Data Logger Screen On or Off. . . . . . . . . . . . . . 124
Turning the Bump Test Function On or Off. . . . . . . . . . . . . . . . . . 125
Turning the Pump Off Screen On or Off . . . . . . . . . . . . . . . . . . . . 126
Updating the Bump Test Parameters . . . . . . . . . . . . . . . . . . . . . . . 127
Updating the Confirmation Beep Setting . . . . . . . . . . . . . . . . . . . . 129
Updating the DataLog Overwrite Setting . . . . . . . . . . . . . . . . . . . 129
Updating the Calibration Interval. . . . . . . . . . . . . . . . . . . . . . . . . . 130
Updating the Calibration Reminder Setting. . . . . . . . . . . . . . . . . . 130
Updating the Calibration Expired Action Setting . . . . . . . . . . . . . 131
Updating the Calibration Check Setting. . . . . . . . . . . . . . . . . . . . . 131
Updating the Bump Test Interval . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Updating the Bump Test Reminder Setting . . . . . . . . . . . . . . . . . . 133
Updating the Bump Test Expired Action Setting . . . . . . . . . . . . . . 133
Updating the Bump Test Check Setting . . . . . . . . . . . . . . . . . . . . . 134
Turning the ID Display Function On or Off . . . . . . . . . . . . . . . . . 135
Updating the LCD Backlight Time Setting. . . . . . . . . . . . . . . . . . . 135
Updating the Autozero Function . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Updating the Demand Zero Function. . . . . . . . . . . . . . . . . . . . . . . 136
Updating the Leak Check/Bar Hole Mode Setting. . . . . . . . . . . . . . 137
Updating the Bar Hole Sampling Time. . . . . . . . . . . . . . . . . . . . . . 138
Turning Portuguese On or Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Updating the Leak Check Mode CO Channel Display Setting. . . . 139
Viewing the ROM/SUM Information. . . . . . . . . . . . . . . . . . . . . . . 140
Turning the Password Function On or Off. . . . . . . . . . . . . . . . . . . 140
Performing a Low Flow Setpoint Adjustment . . . . . . . . . . . . . . . . 141
Exiting Maintenance Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Chapter 7: Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Replacing or Recharging the Batteries . . . . . . . . . . . . . . . . . . . . . . . . . 146
Replacing Alkaline Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Replacing the Lithium Ion Battery Pack . . . . . . . . . . . . . . . . . . . . . 147
Recharging the Lithium Ion Battery Pack in the Instrument . . . . . 148

GX-2012 Operator’s Manual Table of Contents
Recharging the Lithium Ion Battery Pack Out of the Instrument . 150
Replacing the LEL and CO Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Replacing a Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Replacing the Hydrophobic Disk Filter, Cotton Filter,
and Wire Mesh Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
Appendix A: Calibrating and Bump Testing
with a Sample Bag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Calibration/Bump Test Supplies & Equipment . . . . . . . . . . . . . . . . . 161
Preparing for Calibration or Bump Testing. . . . . . . . . . . . . . . . . . . . . 162
Calibrating the GX-2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
Calibrating with the Auto Calibration Method. . . . . . . . . . . . . . . . 165
Calibrating with the Single Calibration Method. . . . . . . . . . . . . . . 168
Bump Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
WARNING: Understand manual before operating. Substitution of
components may impair intrinsic safety. To prevent ignition
of a hazardous atmosphere, batteries must only be changed
or charged in an area known to be nonhazardous. Not tested
in oxygen enriched atmospheres (above 21%).

GX-2012 Operator’s Manual Overview • 1
Chapter 1: Introduction
Overview
This chapter briefly describes the GX-2012. This chapter also describes the
GX-2012 Operator’s Manual (this document). Table 1 at the end of this
chapter lists the specifications for the GX-2012.
About the GX-2012
Using an advanced detection system consisting of up to five gas sensors, the
GX-2012 sample draw gas monitor detects the presence of combustible gas,
oxygen (O2), carbon monoxide (CO), and hydrogen sulfide (H2S)
simultaneously. The GX-2012’s compact size and easy-to-use design makes
it ideally suited for a wide range of applications, including sewage treatment
plants, utility manholes, tunnels, hazardous waste sites, power stations,
petrochemical refineries, mines, paper mills, drilling rigs, and fire fighting
stations. The GX-2012 offers a full range of features, including:
• Simultaneous four-gas monitoring of combustible gases, O2, CO, and H2S
(in Normal Mode)
• Choice of two operating modes: Normal Mode for typical confined space
or area monitoring and Bar Hole Mode for checking of bar holes when
searching for underground gas leaks
• Sample-drawing pump with up to 50-foot range
• Liquid crystal display (LCD) for complete and understandable
information at a glance
• Distinctive audible/vibrating alarms for dangerous gas conditions and
audible alarms for unit malfunction
• Microprocessor control for reliability, ease of use, and advanced
capabilities
• Alarm trend data (when used in Normal Mode)
• Data logging functions (when used in Normal Mode)
• STEL/TWA (when used in Normal Mode) and over range alarm display
• Peak hold and average readouts (when used in Normal Mode)
• Built-in time function
• RF shielded high impact plastic case

2 • About the GX-2012 GX-2012 Operator’s Manual
• ATEX certification for II1G Ex ia IIC T4 Ga
WARNING: The GX-2012 detects oxygen deficiency, elevated levels of
oxygen, combustible gases, carbon monoxide, and hydrogen
sulfide, all of which can be dangerous or life threatening.
When using the GX-2012, you must follow the instructions
and warnings in this manual to assure proper and safe
operation of the unit and to minimize the risk of personal
injury. Be sure to maintain and periodically calibrate the GX-
2012 as described in this manual.

GX-2012 Operator’s Manual Specifications • 3
Specifications
Table 1: GX-2012 Specifications
Target Gas %LEL
Combustible
Gas
(Methane
Calibration
Standard)*
% Volume
Combustible
Gas
(Methane
Calibration
Standard)
Oxygen (O2) Hydrogen
Sulfide
(H2S)
Carbon
Monoxide
(CO)
Range
(Increment) 0-100% LEL (1% LEL) 0 - 100% vol (1% vol) 0-40.0% vol (0.1 vol%) 0-100 ppm (0.5 ppm) 0-500 ppm (1 ppm)
Leak Check
Mode
Range
(Increment)
0-5,000 ppm
(100 ppm)
NOTE: Detection
range is 0-5,000
ppm, but displayed
range can be set to
0-500 ppm, 0-1000
ppm, 0-2000 ppm,
or 0-5000 ppm.
N/A N/A N/A N/A
Sampling
Method Sample Draw
Response
Time T90 Within 30 Seconds
Accuracy ± 5% of reading
or ± 2% LEL
(whichever is
greater)
± 5% of
reading or
± 2% full
scale
(whichever
is greater)
± 0.5% O2± 5% of
reading or
±2ppmH2S
(whichever
is greater)
± 5% of
reading or
± 5 ppm
CO
(whichever
is greater)
Display Digital LCD Display
Gas Alarms
(Factory
Settings)
Alarm 1
10% LEL
Alarm 2
50% LEL
None Alarm 1
19.5 vol%
(Decreasing)
Alarm 2
23.5 vol%
(Increasing)
Alarm 1
5 ppm
Alarm 2
30 ppm
TWA
1 ppm
STEL
5 ppm
Alarm 1
25 ppm
Alarm 2
50 ppm
TWA
25 ppm
STEL
200 ppm
Operating
Temperature
& Humidity
-20°C to 50°C/Below 85% RH (Without Condensation)

4 • About this Manual GX-2012 Operator’s Manual
About this Manual
The GX-2012 Operator’s Manual uses the following conventions for notes,
cautions, and warnings.
NOTE: Describes additional or critical information.
CAUTION: Describes potential damage to equipment.
WARNING: Describes potential danger that can result in injury or death.
Safety/
Regulatory • ATEX: II 1 G Ex ia IIC T4 Ga
Certificate Number DEKRA 11ATEX0123
• IECEx: Ex ia IIC T4 Ga
Certificate Number DEK 11.0045
Power
Supply • Three AA size alkaline batteries standard
• Lithium Ion Battery Pack (3.7 VDC Nominal) optional, Direct Charging
Continuous
Operating
Hours
@ 25 °C
• Alkaline Batteries: 15 Hours (Non Alarm Operation, Fully Charged)
• Lithium Ion Battery Pack: 10 Hours (Non alarm Operation, Fully Charged)
Case High-impact Plastic with protective rubber layer, RF Shielded, Dust and
Weather Proof
Standard
Accessories • 10 foot hose
• 10 inch probe
• Flexible 4 inch tapered rubber nozzle
Optional
Accessories • Rechargeable Lithium-Ion Battery Pack
• 115 VAC Charging Station
• 12 VDC Charging Station
• Data Logger Management Program
• IrDA/USB Cable for Downloading Data to a Computer With Data Logger
Management Program Software (not needed if computer has an infrared
port)
• SDM-2012 Automatic Calibration Station & Software
• Various Probes (see “Parts List” on page 177)
Dimensions
and Weight Approximately 171(H) x 65(W) x 39(D) mm (5.6”H x 2.5”W x 1.5”D) Approximately 310 g (11 oz.)
*Some versions of the GX-2012 are available with the LEL sensor factory set for HC (general
hydrocarbons) and calibrated to isobutane. Consult RKI Instruments, Inc. for further
information.

GX-2012 Operator’s Manual Overview • 5
Chapter 2: Description
Overview
This chapter describes the GX-2012 instrument and accessories.
Instrument Description
The instrument includes the case, sensors, LCD, control buttons, printed
circuit boards, alarm LED’s, infrared communication port, buzzer, vibrator,
batteries, pump, flow chamber, and inlet filter holder.
Figure 1: Components of the GX-2012, Front & Back
Inlet Fitting
Exhaust
Tapered
Rubber
Nozzle
Battery
Cover
(alkaline
version)
Charging
Contacts
Inlet Filter
Holder
Buzzer
Opening
RESET
SILENCE
DISPLAY
(ADJ)
AIR
(SHIFT)
POWER
ENTER
Wrist Strap Installation Feature
IR Port
(behind
button label)
Flow
Chamber
Control
Buttons
LCD
Alarm
LED
Arrays

6 • Instrument Description GX-2012 Operator’s Manual
Figure 2: Components of the GX-2012, Bottom
Case
The Model GX-2012’s sturdy, high-impact plastic case is radio frequency
(RF) resistant and is suitable for use in many environmental conditions,
indoors and out. The case is dust proof and weather resistant. A rubber layer
on the outside of the case protects it from scratches and impact damage.
A clear plastic window through which the LCD can be viewed is located on
the front of the case. Four brass charging contacts that are used when the GX-
2012 is placed in the charging station are on the back of the case. Both the
rechargeable and alkaline versions include a removable battery pack. The
battery pack release latch is on the bottom. The alkaline battery version also
includes a battery cover release knob. The battery pack and flow chamber are
located on the back of the GX-2012. The inlet filter holder is located on the
top of the GX-2012 case.
Sensors
The GX-2012 uses up to five sensors to monitor combustible gas, oxygen
(O2), carbon monoxide (CO), and hydrogen sulfide (H2S) simultaneously.
The sensors are located inside the GX-2012 and are held in their sockets by
the flow chamber. The sensors use different detection principles, as described
below.
Rechargeable Version
Battery Pack
Battery Pack
Release Latch
Battery Cover
Release Knob
Alkaline Version

GX-2012 Operator’s Manual Instrument Description • 7
Combustible Gas Sensors
% LEL/ppm Sensor (NC-6264A)
The % LEL/ppm sensor detects combustible gas in the % LEL and ppm
range. It uses a catalytic element for detection. The reaction of gas with
oxygen on the catalyst causes a change in the resistance of the element which
affects the current flowing through it. The current is amplified by the GX-
2012’s circuitry, converted to a measurement of combustible gas
concentration, and displayed on the LCD.
%Volume Sensor (TE-7561)
The % volume sensor detects combustible gas in the % volume range. It uses
a thermal conductivity (TC) element for detection. The presence of
combustible gas cools the element causing a change in the resistance of the
element which affects the current flowing through it. The current is amplified
by the GX-2012’s circuitry, converted to a measurement of combustible gas
concentration, and displayed on the LCD.
Oxygen Sensor
The O2sensor is a galvanic type of sensor. A membrane covers the cell and
allows gas to diffuse into the cell at a rate proportional to the partial pressure
of oxygen. The oxygen reacts in the cell and produces a voltage proportional
to the concentration of oxygen. The voltage is measured by the GX-2012’s
circuitry, converted to a measurement of gas concentration, and displayed on
the LCD.
CO and H2S Sensors
The CO and H2S sensors are electrochemical cells that consist of two
precious metal electrodes in a dilute acid electrolyte. A gas permeable
membrane covers the sensor face and allows gas to diffuse into the
electrolyte. The gas reacts in the sensor and produces a current proportional
to the concentration of the target gas. The current is amplified by the GX-
2012’s circuitry, converted to a measurement of gas concentration, and
displayed on the LCD.

8 • Instrument Description GX-2012 Operator’s Manual
Dummy Sensors
Any unit that has less than 5 sensors will have a dummy sensor installed in
one or more sensor positions. Dummy sensors are factory installed. The flat
top of the dummy sensor should face up and the bottom hollow side should
face down. The unit shown below is a standard 4-sensor unit for LEL/O2/
H2S/CO and has a dummy sensor installed in the %volume combustible
sensor position.
Figure 3: Dummy Sensor
LCD
A digital LCD (liquid crystal display) is visible through a clear plastic
window on the front of the case. The LCD display simultaneously shows the
gas reading for all installed sensors. The display also shows information for
each of the GX-2012’s program modes.
Bottom
Hollow Side
Dummy Sensor
Top Flat
Side

GX-2012 Operator’s Manual Instrument Description • 9
Control Buttons
Five control buttons are located below the LCD. They are arranged around a
central button, the POWER ENTER button. The DISPLAY (ADJ) button is
on the left, the RESET SILENCE button on the right, the AIRSbutton on
the top, and the (SHIFT)Tis on the bottom.
Printed Circuit Boards
The GX-2012 printed circuit boards analyze, record, control, store, and
display the information collected. The circuit boards are located inside the
case. They are not user serviceable.
Alarm LED Arrays
Three red alarm LED (light emitting diode) arrays are visible through frosted
plastic lenses in the case. One is on the top front, one on the left side, and one
on the right side. The alarm LED arrays alert you to gas, low battery, and
failure alarms.
Infrared Communications Port
An infrared (IR) communications port is located just below the RESET
SILENCE button. The signal goes through the control button material. The
data transmitted through the port is in standard IrDA protocol. A computer’s
infrared port or an IrDA/USB cable connected to a computer’s USB port can
be used to download data saved by the GX-2012 to a computer using the GX-
2012 Data Logger Management Program. See the GX-2012 Data Logger
Management Program operator’s manual for data logging and downloading
instructions.
Table 2: GX-2012 Control Button Functions
Button Function(s)
POWER ENTER • turns the GX-2012 on and off.
• used during setup and calibration.
RESET SILENCE silences and resets audible alarm if the GX-2012 is programmed
for latching alarms and the alarm silence option is on 1
DISPLAY (ADJ) • activates Display Mode
• enters instructions into the GX-2012’s microprocessor
AIRS• activates the demand-zero function (automatically adjusts the
GX-2012 in fresh-air conditions)
• scrolls through the display and settings modes
(SHIFT)T• scrolls through the display and settings modes
• enters instructions into the GX-2012’s microprocessor
1The GX-2012’s alarms are user-adjustable. See “Chapter 6: Maintenance Mode” on page 100.

10 • Instrument Description GX-2012 Operator’s Manual
Buzzer
One solid-state electronic buzzer is located inside the case. Holes on the top
front of the case allow the sound to exit the case. The buzzer sounds for gas
alarms, malfunctions, low battery voltage, and as an indicator during use of
the GX-2012’s many display and adjustment options.
Vibrator
A vibrating motor inside the GX-2012 case vibrates for gas alarms, unit
malfunctions, and as an indicator during normal use of the various modes of
the GX-2012.
Batteries
Three AA-size alkaline batteries (standard) or an optional rechargeable
lithium ion battery pack (3.7 VDC) power the GX-2012. Instrument run time
is dependent upon battery type. At 25°C the alkaline batteries last up to 15
hours and the lithium ion battery pack lasts up to 10 hours. The battery icon
in the upper right of the LCD shows remaining battery life.
When the GX-2012 detects a low battery voltage, a low battery warning is
activated. When battery voltage is too low for normal operation, the GX-
2012 sounds a dead battery alarm.
The alkaline batteries can be replaced by removing the battery cover on the
back of the case. The lithium ion pack can be replaced by removing the entire
battery pack. Push the battery pack latch on the bottom of the unit toward the
front of the unit to release the pack.
The lithium ion battery pack can be recharged by placing the GX-2012 in its
optional battery charging station or by placing the battery pack in the
charging station.
WARNING: To prevent ignition of a hazardous atmosphere, batteries
must only be changed or charged in an area known to be
nonhazardous.

GX-2012 Operator’s Manual Instrument Description • 11
Pump
A diaphragm pump inside the GX-2012 draws the sample to the sensors. It
can draw sample from as far as 50 feet from the GX-2012. The pump is not
user serviceable.
CAUTION: Sample hose lengths of more than 50 feet are not recommended
for the GX-2012 because of flow rate reduction.
Flow Chamber
The flow chamber is on the back of the GX-2012 and is held in place by three
phillips screws. The flow chamber seals to the rubber sensor gasket which
seals to the sensor faces inside the GX-2012 and routes flow from the pump
to the sensors and to the exhaust port (also a part of the flow chamber).
Sensors and Filters
The sensors are located underneath the flow chamber and are only accessible
if you remove the flow chamber and the sensor gasket.
An H2S removal filter disk is placed into a recess in the sensor gasket over
the %LEL sensor. It prevents H2S in the ambient air from reaching the unit’s
combustible gas sensor. Removing H2S that is present in the monitored air
prolongs the life of the sensor. The H2S filter disk is dark red in color and
although it may darken over time, its color is not indicative of remaining
filter life. The H2S filter disk can absorb H2S for 33 ppm hours and should be
replaced after that much exposure. With this many ppm hours of absorption,
the H2S filter disk should be replaced after 80 minutes of exposure to 25 ppm
H2S. This equates to replacing the H2S filter disk after 40 2-minute
calibrations with a cylinder containing 25 ppm H2S. If H2S exists in the
monitoring environment, the H2S filter disk will have to be replaced more
frequently.
A charcoal filter is placed into a recess in the sensor gasket over the CO
sensor. The charcoal filter is black, has a woven texture, and is impregnated
with an H2S absorbing material. The CO sensor will respond if exposed to
H2S and certain hydrocarbon gases. The charcoal filter disk scrubs these
gases out of the sample to avoid false CO readings. If false or elevated CO
readings are noticed, especially in the presence of H2S, change the charcoal
filter.
Inlet Filter Holder
The filter holder is a clear plastic dome shaped piece on the top of the case. A
male quick connect fitting is located on the inlet filter holder. This is the GX-

12 • Standard Accessories GX-2012 Operator’s Manual
2012’s inlet fitting. A cotton dust filter is inside the filter holder. The filter
holder may be removed by turning it counterclockwise and pulling it away
from the case. Two flat membrane disk hydrophobic filters, a wire mesh disk,
and a rubber filter retaining gasket are held in place by the filter holder and
are located in the bottom of the case chamber where the filter holder is
installed.
Standard Accessories
The standard accessories include the tapered rubber nozzle, belt clip, sample
hose, and 10 inch probe. An optional bar hole probe is also available and is
described at the end of this section.
Tapered Rubber Nozzle
A cone shaped 4 inch long rubber nozzle is included with the GX-2012 as
standard. It can be installed on the inlet fitting by pushing the larger end over
it. The smaller end can be inserted through a hole in a wall or some other
access to an enclosed area to sample the environment.
Belt Clip
A belt clip can be mounted to the back of the case using 3 phillips head
screws. The belt clip allows the GX-2012 to be securely attached to a belt.
Wrist Strap
A wrist strap is included with the GX-2012 and can be attached to the right or
left wrist strap installation feature.
Sample Hose & 10 Inch Probe
A 10 foot sample hose and a 10 inch probe are included as standard with the
GX-2012. When desired, the rubber nozzle may be removed and the sample
hose and 10 inch probe may be connected to the inlet fitting. Sample hose
lengths are available from 10 feet to 50 feet (see “Parts List” on page 158).
The quick connect end of the sample hose connects to the inlet fitting of the
GX-2012 and the probe screws onto the end of the hose with the threaded
fitting.
CAUTION: Sample hose lengths of more than 50 feet are not recommended
for the GX-2012 because of flow rate reduction.