RKI Instruments 72-0290-22-B, 72-0290-22-C-51, 72-0290-22-A, 72-0290-22-C, 72-0290-09-A User manual

GX-2012

Operator’s Manual

Part Number: 71-0335

Revision: G

Released: 12/20/21

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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.
For most applications, typical calibration frequencies are
between 3 and 6 months but can be more or less often based on
your usage.

GX-2012 Operator’s Manual

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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.

Absorbent cartridges

Filter elements, disks, or sheets

Pump diaphragms and valves

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. IN NO 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.

Warranty GX-2012 Operator’s Manual

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Table of Contents

Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

About the GX-2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Chapter 2: Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Instrument Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

LCD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Control Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Printed Circuit Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Alarm LED Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Infrared Communications Port. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Buzzer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Vibrator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Flow Chamber. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Sensors and Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Inlet Filter Holder. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Standard Accessories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Tapered Rubber Nozzle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Belt Clip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Wrist Strap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Sample Hose & 10 Inch Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Charging Stations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Optional Probes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Purge Tee Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

External Dilution Fitting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Chapter 3: Using the GX-2012 in Normal Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Start Up, Normal Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Turning On the GX-2012, Normal Mode Only . . . . . . . . . . . . . . . . . . . . . . . . . 23

Turning On the GX-2012 in Normal With All Modes Active . . . . . . . . . . . . . . 28

Performing a Fresh Air Adjustment, Normal Mode . . . . . . . . . . . . . . . . . . . . . . 30

Turning Off the GX-2012, Normal Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Measuring Mode, Normal Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Monitoring an Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Using Optional Probes and Fittings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Combustible Gas Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

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Snap Log Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Measuring Mode, Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Alarm Indications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Resetting and Silencing Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Responding to Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Inert Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Start Up and Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Display Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

HC Range Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Peak Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

STEL Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

TWA Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Alarm Points Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Operation Time Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Date/Time Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Datalogging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

SDM-2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Calibration Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Calibration/Bump Test Supplies and Equipment. . . . . . . . . . . . . . . . . . . . . . . . . 56

Preparing for Calibration or Bump Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Calibrating the GX-2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Bump Testing the GX-2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Chapter 4: Using the GX-2012 in Bar Hole Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69

Start Up, Bar Hole Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Turning On the GX-2012, Bar Hole Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Performing a Fresh Air Adjustment, Bar Hole Mode . . . . . . . . . . . . . . . . . . . . . 74

Bar Hole Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Performing a Bar Hole Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Turning Off the GX-2012, Bar Hole Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Chapter 5: Using the GX-2012 in Leak Check Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78

Start Up, Leak Check Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Turning on the GX-2012, Leak Check Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Performing a Fresh Air Adjustment, Leak Check Mode . . . . . . . . . . . . . . . . . . . 84

Leak Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85

Setting the Display Range Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Locating a Leak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Overscale Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

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Turning the Alarm On and Off in Leak Check Mode . . . . . . . . . . . . . . . . . . . . . 87

Peak Hold Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Snap Log Mode, Leak Check Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Viewing Snap Log Data in Leak Check Mode Operation. . . . . . . . . . . . . . . . . . . 90

Turning Off the GX-2012, Leak Check Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Chapter 6: Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93

Tips for Using Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Using Maintenance Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Updating the Date and Time Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Performing a Fresh Air Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Calibrating Using Auto Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Calibration Using Single Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Performing a Bump Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Turning the Lunch Break Setting On or Off . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Updating the Alarm Latching Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Updating the Alarm Silence Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Updating the Data Logging Interval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Updating the Alarm Point Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Turning the Clear Data Logger Screen On or Off. . . . . . . . . . . . . . . . . . . . . . . 114

Turning the Bump Test Function On or Off . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

Turning the Pump Off Screen On or Off. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

Updating the Bump Test Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

Updating the Confirmation Beep Setting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Updating the DataLog Overwrite Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Updating the Calibration Interval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Updating the Calibration Reminder Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Updating the Calibration Expired Action Setting . . . . . . . . . . . . . . . . . . . . . . . 119

Updating the Calibration Check Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Updating the Bump Test Interval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Updating the Bump Test Reminder Setting. . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Updating the Bump Test Expired Action Setting . . . . . . . . . . . . . . . . . . . . . . . 121

Updating the Bump Test Check Setting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Turning the ID Display Function On or Off. . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Updating the LCD Backlight Time Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Updating the Autozero Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Updating the Demand Zero Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Updating the Leak Check/Bar Hole Mode Setting . . . . . . . . . . . . . . . . . . . . . . . 125

Updating the Bar Hole Sampling Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Turning Portuguese On or Off. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Updating the Leak Check Mode CO Channel Display Setting . . . . . . . . . . . . . 127

Viewing the ROM/SUM Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Turning the Password Function On or Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Performing a Low Flow Setpoint Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . 129

Exiting Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

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Chapter 7: Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Replacing or Recharging the Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

Replacing Alkaline Batteries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

Replacing the Lithium Ion Battery Pack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

Recharging the Lithium Ion Battery Pack in the Instrument . . . . . . . . . . . . . . 136

Recharging the Lithium Ion Battery Pack Out of the Instrument. . . . . . . . . . . 138

Replacing the LEL and CO Filters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

Replacing a Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

Replacing the Hydrophobic Disk Filter, Cotton Filter,

and Wire Mesh Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Chapter 8: Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Appendix A: Calibrating and Bump Testing with a Sample Bag . . . . . . . . . . . . . . . . . 148

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Calibration/Bump Test Supplies & Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Preparing for Calibration or Bump Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

Calibrating the GX-2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

Calibrating with the Auto Calibration Method . . . . . . . . . . . . . . . . . . . . . . . . . 151

Calibrating with the Single Calibration Method . . . . . . . . . . . . . . . . . . . . . . . . 154

Bump Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

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%).

Table of Contents GX-2012 Operator’s Manual

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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

• 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 in stru cti ons an d w arnin gs in th is m anual to as sure
proper and safe operation of the unit and to minimize the risk of
personal injury. Be sure to maintain and periodically calibrate the GX­2012 as described in this manual.

8 • O v e r v i e w GX-2012 Operator’s Manual

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Specifications

Table 1: GX-2012 Specifications

Target Gas %LEL

Combustible

Gas

(Methane
Calibration
Standard)*

Range

(Increment)

Leak Check

Mode

Range

(Increment)

0-100% LEL

(1% LEL)

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.

Sampling

Method

Response

Time

% Volume

Combustible

Gas

Oxygen (O

) Hydrogen

2

Sulfide

S)

(H

2

(Methane

Calibration

Standard)

0 - 100% vol

(1% vol)

0-40.0% vol

(0.1 vol%)

0-100 ppm

(0.5 ppm)

N/A N/A N/A N/A

Sample Draw

T90 Within 30 Seconds

Carbon

Monoxide

(CO)

0-500 ppm

(1 ppm)

Accuracy ± 5% of reading

or ± 2% LEL

(whichever is

greater)

± 5% of

reading or

± 2% full

scale

(whichever

is greater)

± 0.5% O

2

± 5% of

readin g o r

± 2 ppm H

(whichever

is greater)

S

2

± 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

Alarm 1

5 ppm

Alarm 2

30 ppm

Alarm 1

25 ppm

Alarm 2

50 ppm

23.5 vol%

Operating

-20°C to 50

(Increasing)

°

C/Below 85% RH (Without Condensation)

TWA

1 ppm

STEL

5 ppm

TWA

25 ppm

STEL

200 ppm

Temperature

& Humidity

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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

Continuous

Operating

Hours

@ 25 °C

Case High-impact Plastic with protective rubber layer, RF Shielded, Dust and

Standard

Accessories

Optional

Accessories

• Three AA size alkaline batteries standard

• Lithium Ion Battery Pack (3.7 VDC Nominal) optional, Direct Charging

• Alkaline Batteries: 15 Hours (Non Alarm Operation, Fully Charged)

• Lithium Ion Battery Pack: 10 Hours (Non alarm Operation , Full y Charged)

Weather Proof

• 10 foot hose

• 10 inch probe

• Flexible 4 inch tapered rubber nozzle

• Rechargeable Lithium-Ion Battery Pack

• 115 VAC Charging Station

• 12 VDC Charging Station

• Product CD, includes 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 163)

Dimensions

and Weight

*Some versions of the GX-2012 are available with the LEL sensor factory set for HC (general
hydrocarbons) and calibrated to isobutane. Consult for further information.

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.)

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.

10 • A b o u t t h i s M a n u a l GX-2012 Operator’s Manual

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Chapter 2: Description

Inlet F ittin g

Exhaust

Tapered
Rubber
Nozzle

Battery
Cover
(alkaline
ve rsion)

Charging
Contacts

Inlet F i lte r

Holder

Buzzer

Opening

RESET

SILENCE

DISPLAY

(ADJ)

AIR

(SHIFT)

POWER

ENTER

Wrist Strap Installation Feature

IR Port
(behind
b u t ton label)

Flow

Chamber

Control
Buttons

LCD

Alarm

LED

Arrays

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

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Case

Rechargeable Version

Battery Pack

Battery Pack

Release Latch

Battery Cover
Release Knob

Alkaline

Version

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 (H
inside the GX-2012 and are held in their sockets by the flow chamber. The sensors use

different detection principles, as described below.

Combustible Gas Sensors

Figure 2: Components of the GX-2012, Bottom

S) simultaneously. The sensors are located

2

% 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.

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%Volume Sensor (TE-7561)

Bottom

Hollow Side

Dummy Sensor

Top F lat

Side

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 O2 sensor 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.

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

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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.

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 AIR button on the top, and the (SHIFT) is
on the bottom.

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 al arm if the GX-2012 is programmed

for latching alarms and the alarm silence option is on

DISPLAY (ADJ) • activates Display Mode

• enters instructions into the GX-2012’s microprocessor

1

AIR • activates the demand-zero function (automatically adjusts the

GX-2012 in fresh-air conditions)

• scrolls through the display and settings modes

(SHIFT) • scrolls through the display and settings modes

• enters instructions into the GX-2012’s microprocessor

1 The GX-2012’s alarms are user-adjustable. See “Chapter 6: Maintenance Mode” on page 93.

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.

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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 i on 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.

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.

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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 H
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
and should be replaced after that much exposure. W ith 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 avoi d false CO rea dings. If

false or elevated CO readings are noticed, especially in the presence of H2S, change the
charcoal filter.

S that is present in the monitored air prolongs the life of the sensor . The H2S

2

S filter disk can absorb H2S for 33 ppm hours

2

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-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.

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Sample Hose & 10 Inch Probe

SampleHose

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 “Chapter 8: Parts List” on page 145). 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.

Figure 4: Sample Hose and Probe

Optional Accessories

Several optional accessories are available for the GX-2012. They include a rechargeable
lithium ion battery pack, charging stations, various special probes, a purge tee fitting, and
a dilution fitting. The most commonly used optional accessories are described below.
Detailed instructions regarding the use of these and other available accessories are
included in other parts of this manual. Data logging accessories are briefly described in
“Data Logging” on page 55.

Rechargeable Lithium Ion Battery Pack

A rechargeable lithium ion battery pack is available for the GX-2012. A fully charged
battery pack will power the GX-2012 for 10 hours. The batteries will last for a minimum
of 500 charge cycles. See the “Chapter 8: Parts List” on page 145 for ordering
information.

Charging Stations

The GX-2012 lithium ion battery pack is charged with the GX-2012 charging station. Two
battery charging stations are available for the GX-2012, the standard AC char gin g station,
and a DC charging station with a vehicle plug adapter.

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AC Powered Charging Station

Charging
Contacts

ChargeLED

AC Adapte r

To AC

Outlet

Adapter Jack

Adapter Jack

Top

ViewRear View

The standard AC powered charging station consists of an instrument charging base and an
AC adapter. The AC adapter plugs into a 115 VAC wall outlet and connects to the
charging station with a jack on the end of a five foot DC output cable. The AC adapter will
also work for 100 VAC or 220 VAC if an appropriate plug adapter is provided. The AC
charging station is shown below in Figure 5.

Figure 5: GX-2012 AC Powered Charging Station

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DC Powered Charging Station

Charging
Contacts

Adapter Jack

To Vehicle

12 VDC

Power Socket

Vehicle Plug

Adapter Jack

Rear View

Charge LED

Top

View

An optional DC powered charging station is available with a vehicle plug 12 VDC
adapter . It uses the same charging base as the AC charging station but comes with a Velcro
strap to secure the GX-2012 in the charging base.

Figure 6: GX-2012 DC Powered Charging Station

Optional Probes

Various optional probes designed for specific applications are available for the GX-2012.
They include the following:

• 30 inch aluminum probe

Figure 7: 30 Inch Aluminum Probe

This probe is designed for applications where it is necessary to put the probe tip in
areas that are out of reach with the standard probe. A small breather hole near the end
of the probe tube prevents interruption of sampling and a low flow alarm if the probe
tip is blocked.

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• 30 inch stainless steel probe

End Plugged

Figure 8: 30 Inch Stainless Steel Probe

This probe is physically the same as the 30 inch aluminum probe and is intended for
applications where a high level of corrosion resistance is required in the long probe
tube.

• Barhole probe

Figure 9: Barhole Probe

An optional bar hole probe is available for the GX-2012. It is designed to be used
when the GX-2012 is operated in Bar Hole Mode to check bar holes when tracking
down underground gas pipe leaks (see “Chapter 4: Using the GX-2012 in Bar Hole
Mode” on page 69). The bar hole probe has the same handle as the standard probe, but
has a 30 inch fiberglass tube instead of the standard tube. Four holes are drilled
through the 30 inch tube’s wall near the end and the end is plugged so that debris from
the barhole cannot be drawn into the tube. The sample is drawn through the drilled
holes in the tube wall.

• 32 inch telescoping probe with dust filter

Figure 10: 32 Inch Telescoping Probe with Dust Filter

This probe is designed for use where it is necessary to put the probe tip in areas not
accessible with the 10 inch probe with dust filter and applications where the probe
tube must be collapsible for storage.

• 7 foot telescoping probe with dust filter

Figure 11: 7 Foot Telescoping Probe with Dust Filter

This probe is designed for use where it is necessary to put the probe tip in areas not
accessible with the 32 inch telescoping probe with dust filter and applications where
the probe tube must be collapsible for storage.

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• 8 meter hose with floating head

Figure 12: 8 Meter Hose with Floating Head

This probe is designed to be used in a tank or a well that may have water or some other
liquid at the bottom. As you lower the probe down, if it hits water, it will float and
continue to monitor the area.

See the “Chapter 8: Parts List” on page 145 for probe ordering information.

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Purge Tee Fitting

GX-2012 I nl et

Pressurized

Stream

Sample Port

Excess
Pressurized
Sample

Vent Port

The 17-4430RK-01 purge fitting is used to detect gas levels in a pressurized gas stream
from a pipeline or vessel being purged. The sample port of the purge fitting is inserted into
the flowing gas, and the vent port will allow any excess gas to release to the atmosphe re to
avoid damage to pump or sensors.

Figure 13: Purge Tee Fitting

External Dilution Fitting

An external dilution fitting is available for the GX-2012. It is a 1:1 dilution fitting and is
designed to mate with the inlet fitting and accept a sample hose or probe. The fittings are
made with brass and nickel plated brass and are appropriate for use with the four standard
gases. The dilution fitting is normally used when it is necessary to introduce air into a
sample that has no oxygen or a very low level of oxygen, such as a nitrogen purged
sample. It can also be used when one of the target ga s levels in the sample ar ea will li kely
be present in a concentration above the detection range for that gas. Since the fittings
partially consist of unplated brass, they are not appropriate for detection of elevated levels
of H2S.

Figure 14: Dilution Fitting

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Chapter 3: Using the GX-2012 in Normal Mode

rESU
4

RESUME

Overview

This chapter explains how to operate the GX-2012 in Normal Mode. Normal Mode is used
to perform confined space entry monitoring or general area monitoring. While in Normal
Mode, Display Mode and Calibration Mode are accessible.

If a standard version of the GX-2012 is ordered, it is shipped with Bar Hole Mode disabled
so that the instrument only runs in Normal Mode when turned on.

Start Up, Normal Mode

This section explains how to start up the GX-2012 in Normal Mode, get it ready for
operation, and turn it off.

NOTE: The screens illustrated in this section are for a 4-gas unit that has the % LEL

range for the combustible gas channel. The screens displayed by your GX-2012
may be slightly different.

Turning On the GX-2012, Normal Mode Only

The following description of the GX-2012 start up sequence assumes that the following
items in Maintenance Mode are turned on: LNCH BRK, ID DISP, CL RMNDR, and BP
RMNDR. If any of these items is turned off, then the corresponding screen will not
appear. This description also assumes that Bar Hole Mode is not active.

1. Connect the tapered rubber nozzle or the sample hose to the GX-2012’s quick connect
inlet fitting.

2. If a sample hose is used, screw the probe onto the sample hose’s threaded fitting.

3. Press and briefly hold down the POWER ENTER button. Release the button when
you hear a beep.

4. If LNCH BRK is turned on, the Resume Datalog Screen displays.

• Press and release the POWER ENTER button to continue accumulating time-

weighted average (TWA), PEAK readings, and time in operation from the last
time the GX-2012 was used. The short-term exposure limit [STEL] reading is
reset each time the GX-2012 is turned on.

• Press and release the DISPLAY(ADJ) button to reset the accumulation of these

measurements.

GX-2012 Operator’s Manual Overview • 23

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If you do not press the POWER ENTER or DISPLAY(ADJ) button within 5 seconds,

CAL

C--LIMIT

FAIL

C--LIMIT

2011
9
30
69d

NEXT CAL

the GX-2012 automatically resumes accumulating the TWA, PEAK readings, and
time in operation.

5. If CL RMNDR is turned on (factory setting), the screen that appears next depends on
how CL EXPRD is set in the Maintenance Mode Menu ((pg. 119)).

• If the unit is due for calibration and CL EXPRD is set to CONFIRM (factory

setting), then the following screen displays.

The alarm LED’s and buzzer will pulse several times. After this, press the
RESET SILENCE button until you hear a beep to continue.

• If the unit is due for calibration and CL EXPRD is set to NOT USE, then the

following screen displays.

The GX-2012 cannot be used until a calibration has been performed either by
selecting AUTO CAL or ONE CAL in the Maintenance Mode menu. See
“Calibrating Using Auto Calibration” on page 97 or “Calibrating Using Single
Calibration” on page 100 for calibration instructions.

• If calibration is not due or CL EXPRD is set to NO EFFECT, then the following

screen appears for a few seconds indicating when the next calibration is due.

24 • S t a r t U p , N o r m al M o d e GX-2012 Operator’s Manual

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6. If BP RMNDR is turned on (factory setting is OFF), the screen that appears next

tESt

B--LIMIT

FAIL

B--LIMIT

2011
9
30
10d

NEXTBUMP

depends on how BP EXPRD is set in the Maintenance Mode Menu ((pg. 119)).

• If the unit is due for a bump test and BP EXPRD is set to CONFIRM (factory

setting), then the following screen displays.

The alarm LED’s and buzzer will pulse several times. After this, press the
RESET SILENCE button until you hear a beep to continue.

• If the unit is due for a bump test and BP EXPRD is set to NOT USE, then the

following screen displays.

The GX-2012 cannot be used until a bump test has been performed by selecting
BUMP in the Maintenance Mode menu. See “Performing a Bump Test” on
page 102 for bump testing instructions.

• If a bump test is not due or BP EXPRD is set to NO EFFECT, then the following

screen appears for a few seconds indicating when the next bump test is due.

NOTE: If both CL RMNDR and BP RMNDR are turned off, a WARM UP screen will

display before the warm up sequence continues.

GX-2012 Operator’s Manual Start Up, Normal Mode • 25

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7. If ID DISP is turned on (see (pg. 123)), the User ID Screen displays for a few seconds

U Id

- - - - - - - -

S Id

- - - - - - - -

2011
8
31
22:39

DATE

and then the Station ID Screen displays for a few seconds.

8. The Date/Time Screen appears for a few seconds.

This screen displays the current year, month, day, and time.

26 • S t a r t U p , N o r m al M o d e GX-2012 Operator’s Manual

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9. The Battery Level and Alarm Pattern Screen appears next.

bAtt

3.7

AL-H V

bAtt

3.7

AL-H D: V

AL -- H indicates latching (hold) alarms and AL -- A indicates self-resetting
(automatic) alarms. The number shown indicates the voltage of the batteries. A fully
charged lithium ion battery pack will display 3.7 V. If the unit is powered by alkaline
(dry cell) batteries, a “D” will appear in front of the “V” in the lower right corner.

10. The display then indicates the following items for about a second each:

• Full scale values for all channels

• Warning setpoint (low gas alarm) for all channels

• Alarm setpoint (high gas alarm) for all channels

• STEL alarm setpoint for the CO and H2S channels

• TWA alarm setpoint for the CO and H2S channels

NOTE: If the combustible channel is factory set as %volume only, all gas alarms are

turned off. You must press and release the RESET SILENCE button at the
warning, alarm, STEL, and TWA screens to acknowledge that there are no gas
alarms. The warm up will not proceed until you do so.

If the combustible channel is set up as %volume only using the HC Range
Screen in Display Mode, it will automatically revert to Autoranging when it is
turned off and on again and the no alarm acknowledgment screen will not
appear.

GX-2012 Operator’s Manual Start Up, Normal Mode • 27

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11. If the GX-2012 experiences a sensor failure during start up, a screen indicating which

FAIL

ppm

SENSOR

CO

0

20.9
0

0.0

%LEL

%

ppm

ppm

CH4

O2

22:37

CO
H2S

sensor failed displays. In the example below, the CO sensor has failed.

If you wish to continue, press and release the RESET SILENCE button to
acknowledge the failure. The gas reading for the failed sensor will be replaced by
“---”. Replace the failed sensor as soon as possible.

12. The GX-2012 is now operating in Normal Mode and monitoring for gas in Measuring
Mode. The Normal Operation Screen appears.

The concentrations of the target gases are displayed along with the time and battery charge
level. The heart symbol displayed just to the left of the battery charge level flashes while
the instrument is functioning properly. If it disappears or is steadily on, the unit is
experiencing a microprocessor error. The fan symbol just to the left of the heart symbol
spins while the pump is operating.

Turning On the GX-2012 in Normal Mode With All Modes Active

If the L./B. MODE item in Maintenance Mode is set to LC, bH, or LC bH (see “Updating
the Leak Check/Bar Hole Mode Setting” on page 125), then the user must select Normal
Mode during the start up sequence to operate in Normal Mode. The standard factory
setting for L./B. MODE is OFF. See “Chapter 4: Using the GX-2012 in Bar Hole Mode”
on page 69 for a description of Bar Hole Mode or “Chapter 5: Using the GX-2012 in Leak
Check Mode” on page 78 for a description of Leak Check Mode.

The following description of the GX-2012 start up sequence assumes that the following
menu items in Maintenance Mode are turned on: LNCH BRK, ID DISP, CL RMNDR,
and BP RMNDR. If any of these items is turned off, then the corresponding screen will
not appear. It also assumes that the L./B. MODE menu item in Maintenance Mode is set
to LC bH. If L./B. MODE is set to LC, the Bar Hole Mode Select Screen will not appear.
If L./B. MODE is set to bH, the Leak Check Mode Select Screen will not appear.

1. Connect the tapered rubber nozzle or the sample hose to the GX-2012’s quick connect
inlet fitting.

2. If a sample hose is used, screw the probe onto the sample hose’s threaded fitting.

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3. Press and briefly hold down the POWER ENTER button. The Normal Mode Select

0

20.9
0

0.0

vol%
%LEL

%

ppm

ppm

CH4

O2

NORMAL ?

CO
H2S

0

20.9
30

vol%
%LEL

%

BAR HOLE MODE

sec

CH4

O2

B.H. MODE?

CO DISP OFF CO DISP On

0

5000

ppm

ppm

LEAK CK MODE

CH4

L.C. MODE?

0
0

5000

ppm

ppm

ppm

LEAK CK MODE

CH4

L.C. MODE?

CO

Screen displays.

4. You can use the AIR button to scroll to the Bar Hole Mode Select Screen.

5. Press the AIR button again to display the Leak Check Mode Select Screen.

NOTE: If the CO DISP parameter in Maintenance Mode is set to On, the CO

channel will appear in Leak Check Mode. If the CO DISP parameter is
set to OFF (factory setting), the CO channel will not appear in Leak
Check Mode. See “Chapter 5: Using the GX-2012 in Leak Check Mode”
on page 78 for more information.

You can scroll up or down through these screens using the AIR or (SHIFT)
buttons.

6. With the Normal Mode Select Screen displayed, press and release the POWER
ENTER button and continue with the startup sequence as described in the previous
section, “Turning On the GX-2012, Normal Mode Only”, from step 4 on page 23 on.

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GX-2012 Operator’s Manual Start Up, Normal Mode • 29

NOTE: If no button is pressed for 20 seconds, the unit will proceed into whichever

7. To exit Normal Mode and return to the Mode Select Screen, press and hold the

mode is displayed.

(SHIFT) button for 5 seconds while in the Normal Operation Screen.

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Performing a Fresh Air Adjustment, Normal Mode

AIr
CAL

HOLD AIR

Before using the GX-2012, it is recommended to set the fresh air readings for the target
gases by performing a fresh air adjustment. This will set the combustible gas, CO, and
H

S channels to zero and the OXY channel to 20.9%.

2

1. Find a fresh-air environment. This is an environment free of toxic or combustible
gases and of normal oxygen content (20.9%).

2. Turn on the unit as described above in “Turning On the GX-2012, Normal Mode
Only” or “Turning On the GX-2012 in Normal Mode With All Modes Active”.

3. Press and hold the AIR button. The display prompts you to hold the AIR button.

4. Continue to hold the AIR button until the displ ay prompts you to release the AIR
button. The GX-2012 will count down from 8 on an autoranging combustible gas
channel as it sets the fresh air reading for all channels. Once the countdown has
finished, start up is complete and the unit is ready for monitoring.

Turning Off the GX-2012, Normal Mode

1. Press and hold the POWER ENTER button.

2. The buzzer will pulse for about three seconds and TURN OFF will be displayed along
the bottom of the screen.

3. Release the button when TURN OFF disappears.

Measuring Mode, Normal Operation

The GX-2012 has three operating modes within Normal Mode: Measuring Mode, Display
Mode, and Calibration Mode. This section describes using the GX-2012 in Measuring
Mode during normal operation.

In Measuring Mode the GX-2012 continuously monitors the sampled atmosphere and
displays the gas concentrations present for its target gases. In a low-light environment,
press and release any button to turn on the display backlight. See “Updating the LCD Back
Light Time Setting” on page 123 to program backlight duration. If the BEEP. SET menu
item in Maintenance Mode is turned on, the GX-2012 beeps once every 5 minutes to
confirm that it’s operating. See “Updating the Confirmation Beep Setting” on page 117 for
instructions to update the setting.

Monitoring an Area

1. Start up the GX-2012 as described above in “Start Up, Normal Mode” on page 23 or
“Turning On the GX-2012 in Normal Mode With All Modes Active”. It is now in

30 • M e a s u r i n g M o d e, N o r m a l O p e r a t i o n GX-2012 Operator’s Manual

Measuring Mode.

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2. Take the GX-2012 to the monitoring area.
If the tapered rubber nozzle is used, put the nozzle tip in the area to be monitored.
If the hose and probe is used, put the probe tip in the area to be monitored.

3. Wait 10 - 15 seconds and observe the display for gas readings. If a reading is
observed, allow the reading to stabilize to determine the gas concentrations present.

NOTE: Response time increases with the length of the sample hose. Long sample hoses

will require more time to show a response at the GX-2012. The maximum
sample hose length recommended for
longer sample hose lengths.

4. If a gas alarm occurs, take appropriate action. See “Responding to Alarms” on
page 40.

the GX-2012 is 50 feet. Consult for

Using Optional Probes and Fittings

This section describes how to use the 8 meter hose with floating head and the purge tee
fitting.

Using the 8 Meter Hose with Floating Head

This probe is designed to be used in a tank or a well that may have water or some other
liquid at the bottom. To use the 8 meter hose with floating probe:

1. Start up the GX-2012 as described in “Start Up, Normal Mode” on page 23.

2. Connect the 8 meter hose with floating probe to the GX-2012’s quick connect inlet
fitting.

3. Slowly lower the probe into the area you wish to monitor. If the probe hits water, it
will float and continue to monitor the area.

Figure 15: 8 Meter Hose with Floating Head

Using the Purge Tee Fitting

The purge fitting is used to detect gas levels i n a pressurized gas stream from a pipeline or
vessel being purged.

1. Start up the GX-2012 as described in “Start Up, Normal Mode” on page 23.

2. Connect the purge tee fitting to the GX-2012’s quick connect inlet fitting.

GX-2012 Operator’s Manual Measuring Mode, Normal Operation • 31

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3. Insert the sample port into the flowing gas. The vent port will allow any excess gas to

GX-201 2 I nl et

Pressurized

Stream

Sample Port

Excess
Pressurized
Sample

Vent Port

release to the atmosphere to avoid damage to pump or sensors.

Figure 16: Purge Tee Fitting

Using the Dilution Fitting

The external dilution fitting is a 1:1 dilution fitting. It is normally used when it is
necessary to introduce air into a sample that has no oxygen or a very low level of oxygen,
such as a nitrogen purged sample. It can also be used when one of the target gas levels in
the sample area will likely be present in a concentration above the detection range for that
gas. Since the fittings partially consist of unplated brass, they are not appropriate for
detection of elevated levels of H2S.

1. Start up the GX-2012 as described in “Start Up, Normal Mode” on page 23.

2. Install the dilution fitting to the GX-2012’s quick connect inlet fitting.

3. Connect the tapered rubber nozzle or the sample hose to the GX-2012’s quick connect

4. If a sample hose is used, screw the probe onto the sample hose’s threaded fitting.

5. Monitor the sampling area.

NOTE: The GX-2012 can be calibrated either with or without the dilution fitting in

CAUTION: If the dilution fitting is in place for calibration, do not use a demand flow

inlet fitting.

place. If calibrated without the dilution fitting in place, then display readings
must be doubled to determine the actual gas concentration. If calibrated with
the dilution fitting in place, then a sample bag must be used during calibration,
and the display readings will be the actual gas concentrations.

regulator. Use a sample bag. The use of a demand flow regulator with a
dilution fitting when calibrating will result in an inaccurate calibration.

Figure 17: Dilution Fitting

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Combustible Gas Detection

The GX-2012 can support two combustible gas sensors, a TC (thermal conductivity)
sensor for detection in the % volume range, and a catalytic sensor for detection in the %
LEL range. Either or both sensors may be installed in your unit.

If both the % volume and % LEL sensors are installed, the combustible gas channel is
setup at the factory as % LEL/% volume autoranging. In this case, the combustible gas
channel will display the combustible gas concentration in % LEL up to 100% LEL. If the
combustible gas concentration rises above 100% LEL, then the unit automatically begins
displaying the concentration in % volume.

CAUTION: If both combustible sensors are installed in your instrument, make sur e you

follow the recommendations in the next section, “Applications with High
Levels of Combustible Gas” on page 33, to protect the % LEL sensor.
Failure to do so will result in damage to the % LEL sensor.

WARNING: If the combustible channel is set for % volume only, then there are no

gas alarms for any detection channel. See “HC Range Screen” on
page 44.

There are three important issues to keep in mind when monitoring for combustible gas.

Applications with High Levels of Combustible Gas

The GX-2012 provides the % LEL sensor with some protection by turning off the % LEL
sensor power temporarily when it determines that a % LEL over scale (more than 100%
LEL) concentration of combustible gas is present. When this happens, “OVER” is
displayed below the gas list and the display units to the right of the combustible gas
channel change to % volume. However, this protection is not adequate to completely
prevent damage to the sensor when it is exposed to moderate or high levels of % volume
gas.

Combustible gas is present at moderate or high % volume levels in many applications
such as purging applications. If your GX-2012 is equipped with both the % LEL and
%volume sensors, you must set up the instrument so that the combustible channel operates
in the %volume only range when you use the instrument for this type of application to
protect the % LEL sensor from damage. You can set the combustible channel to operate in
the % volume range only in the HC Range Screen of Display Mode. See “HC Range
Screen” on page 44 for instructions to set the combustible channel to operate in the %
volume range only.

CAUTION: Failure to set the combustible channel to % volume only operation when

using the GX-2012 for applications wit h moderate t o high % vo lume levels
of combustible gas will result in damage to the % LEL sensor.

The instrument may be set up for combustible channel autoranging operation when it is
used for confined space applications where % volume combustible gas concentrations are
not likely to be found.

Silicone & Other Potentially Damaging Compounds

Silicone vapors and chlorine and fluorine compounds, such as chlorinated hydrocarbons,
can damage the %LEL sensor. These compounds should be avoided. If exposure to these
compounds is suspected, verify the %LEL response on a known gas sample.

GX-2012 Operator’s Manual Measuring Mode, Normal Operation • 33

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%LEL Sensor Relative Responses

Although the standard factory setup and calibration for the combustible gas channel is to
methane (CH4), the combustible sensors will respond to other combustible gases as well.

The table below lists the conversion factors for several hydrocarbon gases for the % LEL
combustible sensor if it is calibrated to methane. Conversion factors are not available
for the % volume TC sensor. To use this table, multiply the display reading on the
combustible gas channel by the factor in the appropriate row to obtain the actual gas
concentration. For example, if you are detecting pentane and the display reads 10% LEL
on the combustible gas channel, you actually have 10% LEL x 1.56 = 15.6% LEL pentane
present.

Table 3: LEL Hydrocarbon Conversions

LEL Conversion

Gas

Acetone 1.79 Iso Butane 1.47

Acetylene 1.92 MEK 2.27

Benzene 2.00 Methane 1.00

Ethane 1.09 Methanol 1.92

Ethanol 2.50 Pentane 1.56

Ethylene 1.06 Propane 1.35

Heptane 2.50 Propylene 1.32

Hexane 2.08 Toluene 3.13

Hydrogen 1.25 Xylene 4.27

IPA 2.78

Factor (Methane

Calibration)

Gas

LEL Conversion
Factor (Methane

Calibration)

Snap Log Mode

The snap logging function in Snap Log Mode allows the user to record data at a specific
time and have it saved to the data logger. The data is assigned a snap log ID and is saved
with the station ID that was in use when the data was taken.

To enter Snap Log Mode and record snap log data:

1. Press and hold the (SHIFT) button, then press and hold the AIR button and hold
both until you hear a beep. The unit will cycle through the following screens.

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2011
9
27
22:37

YES/ENT.

34

19.2
10

7.8

%LEL

%

ppm

ppm

CH4

O2

NO /DISP

CO

H2S

no
016

REC. DATA

S Id

001

GX-2012 Operator’s Manual Measuring Mode, Normal Operation • 35

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The first screen displays what snap log ID will be given to this particular set of data.
This ID number increases sequentially with each set of snap log data taken. The
second screen displays what Station ID will be associated with this snap log. The third
screen displays the year, month, day, and time of the snap log, and that you should
press the POWER ENTER button to save a set of snap log data. The fourth screen

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displays the current gas readings, and that you should press the DISPLAY (ADJ)

S Id
SEL

001

SAVED

button to exit Snap Log Mode without saving a set of snap log data.

2. You can change the Station ID to be used with the snap log by pressing the (SHIFT)
button and then pressing the DISPLAY (ADJ) button. The Station ID Select Screen
will appear and the current Station ID will be flashing.

3. Use the (SHIFT) and AIR buttons to scroll to the desired station ID, then press
and release the POWER ENTER button to return to the Snap Logging Screen
sequence.

T o return to the Snap Logging Screen sequence without changing the station ID, press
and release RESET SILENCE.

4. To take a snap log of the current gas readings, press and release the POWER ENTER
button. The unit will display SAVED along the bottom of the screen before returning
to the Snap Logging Screen sequence.

To exit Snap Log Mode without taking a snap log or when you are finished recording
snap logs, press and release the DISPLAY (ADJ) button. The unit will immediately
return to the Normal Operation Screen.

5. The data recorded in Snap Log Mode can be viewed in Display Mode. See “Snap
Logging Screen” on page 53 for more information.

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Measuring Mode, Alarms

This section covers alarm indications in Measuring Mode. It also tells you how to reset the
GX-2012 after an alarm has occurred and how to respond to an alarm condition.

NOTE: False alarms may be caused by radio frequency (RF) or electromagnetic (EMI)

interference. Keep the GX-2012 away from RF and EMI sources such as radio
transmitters or large motors.

Alarm Indications

CAUTION: If the combustible channel is set for %volume only, then there are no gas

alarms for any detection channel. See “HC Range Screen” on page 44.

The GX-2012 will sound an alarm, the unit will vibrate, and the LED arrays will flash
when one of the target gas concentrations rises above the Warning level, or in the case of
oxygen, falls below the Low Alarm setting for that gas.

The GX-2012 also sounds an alarm, vibrates, and flashes the LED arrays when the Alarm
level is reached for combustible gas, CO, and H2S, when the concentration of oxygen rises

above the High Alarm level, and when the STEL and TWA alarm points are reached for
CO and H2S.

When a failure condition occurs, such as a sensor failure, low flow, or dead battery
condition, the unit will also sound an alarm, flash the LED arrays, and vibrate.

The table below summarizes the types of alarms produced by the
GX-2012.

Table 4: Alarm Types and Indications

Alarm Type Visual Indications Other Indications

Low Alarm

Concentration of gas

rises above the Warni ng

level, or falls below the
Low Alarm level for O

High Alarm

Concentration of gas

rises above the Alarm
level, or rises above t he
High Alarm level for O

• WARNING appears
below the gas list.

• Reading for the gas in
alarm flashes

• Alarm LED arrays

.

2

2

flash

• Backlight turns on

• ALARM appears
below the gas list.

• Reading for the gas in
alarm flashes

• Alarm LEDs flash

.

faster than warning
indication

• Backlight turns on

• Buzzer sounds
alternating between a
low and high pitch

• Vibrator pul ses

• Buzzer sounds
alternating between
low and high pitch
faster than warning
indication

• Vibrator pulses faster
than warning
indication

GX-2012 Operator’s Manual Measuring Mode, Alarms • 37

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Table 4: Alarm Types and Indications

Alarm Type Visual Indications Other Indications

TWA or STEL

Concentration of CO or

S rises above the

H

2

TWA or STEL alarm

point setting.

Over Range*

Low Flow*

• TWA or STEL appears
below the gas list.

• Alarm LEDs flash

• Back light turns on

• Gas reading replaced
by brackets flashing at
same rate as alarm
indication

• Alarm LEDs flash at
same rate as alarm
indication

• Back light turns on.

• OVER appears below
the gas list.

• The display indicates

FAI L LOW FLOW

• The Alarm LED’s flash

• Buzzer sounds
alternating between a
low and high pitch at
the same rate as
warning indication

• Vibrator pul ses at
same rate as warning
indication

• Buzzer sounds
alternating between a
low and high pitch at
same rate as alarm
indication

• Vibrator pul ses at
same rate as alarm
indication

• Buzzer sounds a
double pulsing tone
(two pulses in quick
succession)

Low Battery

Warning*

Dead Battery Alarm*

Sensor Failure*

• Battery icon blinks • None

• Gas readings
replaced by FAIL

• Fan symbol
disappears

• BATTERY disp layed
along bottom of
screen

• Alarm LED arrays
flash

• FAIL appears at the
bottom of the display
and the failed
sensor(s) are
indicated

• Alarm LED arrays
flash

Buzzer sounds a double
pulsing tone (two pulses

in quick succession)

Buzzer sounds a double
pulsing tone (two pulses

in quick succession)

38 • M e a s u r i n g M o d e , A la r m s GX-2012 Operator’s Manual

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Table 4: Alarm Types and Indications

Alarm Type Visual Indications Other Indications

Clock Failure*

System Failure*

Microprocessor

Failure*

• NOTE: The unit will
not operate if this
alarm occurs.

• F AIL CLOCK appears
on the display

• Alarm LED arrays
flash

• FAIL SYSTEM
appears on the
display

• Alarm LED arrays
flash

• Heart indicator is
steadily on or not on
at all

Buzzer sounds a double
pulsing tone (two pulses

in quick succession)

• Buzzer sounds a
double pulsing tone
(two pulses in quick
succession)

• A failure code appears

• None

*This alarm can also occur in Bar Hole Mode

Resetting and Silencing Alarms

You can set the GX-2012’s gas alarms as latching or self-resetting alarms (see “Updating
the Alarm Latching Setting” on page 108) and the buzzer operation as silenceable or not
silenceable (see “Updating the Alarm Silence Setting” on page 109).

• Self-resetting alarms (LATCHING set to OFF)

Self-resetting alarms automatically shut off and reset when the gas reading falls below
(or rises above for an oxygen low alarm) the alarm setting. You cannot silence or reset
self-resetting alarms.

• Latching alarms (LATCHING set to ON)

You can set latching alarms with or without Alarm Silence (see “Updating the Alarm
Silence Setting” on page 109).

With ALRM SLNC ON and LATCHING ON:

When the GX-2012 goes into a gas alarm, press the RESET SILENCE button to silence
the buzzer. If the gas concentration was still above the alarm level when the button was
pressed, the LEDs continue to flash, and the GX-2012 continues to display the current
alarm level.

The gas reading must fall below (or rise above for an oxygen low alarm) the low alarm
setting before you can reset the alarm. Press the RESET SILENCE button to reset the
alarm. The LEDs turn off and the GX-2012 alarm indications on the display turn off.

GX-2012 Operator’s Manual Measuring Mode, Alarms • 39

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With ALRM SLNC OFF and LATCHING ON:

The gas reading must fall below (or rise above for an oxygen low alarm) the low alarm
setting before you can reset the alarm. Press the RESET SILENCE button to reset the
alarm. The LEDs and buzzer turn off and the GX-2012 alarm indications on the display
turn off.

NOTE: With ALRM SLNC set to OFF in Maintenance Mode, you cannot silence the

buzzer while the gas reading is above (below for an oxygen Low Alarm) the
low alarm setting.

Responding to Alarms

This section describes response to gas, over range, battery, and sensor failure alarms.

Responding to Gas Alarms

1. Determine which gas alarm has been activated.

2. Follow your established procedure for an increasing gas condition or a decreasing
oxygen condition.

3. If necessary, reset the alarm using the RESET SILENCE button once the alarm
condition has been cleared.

Responding to Over Range Alarms

WARNING: An over range alarm may indicate an extreme combustible gas, toxic

gas, or oxygen concentration. Confirm a normal condition with a
different GX-2012 or with another gas detecting device.

1. Determine which gas al

2. Follow your established procedure for an increasing gas condition.

3. Reset the alarm using the RESET SILENCE button once the alarm condition has

cleared.

4. Calibrate the GX-2012 as described in the calibration section of this manual.

5. If the over range condition continues, you may need to replace the sensor that has

triggered the over range alarm.

6. If the over range condition continues after you have replaced the sensor, contact for
further instructions.

arm has been activated.

40 • M e a s u r i n g M o d e , A la r m s GX-2012 Operator’s Manual

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Responding to Battery Alarms

FAIL
031

SYSTEM

WARNING: The GX-2012 is not operational as a gas monitoring device during a

dead battery alarm. Take the GX-2012 to a non-hazardous area and
replace or recharge the batteries as described in “Replacing or
Recharging the Batteries” on page 134.

The GX-2012 is fully functional during a low battery warning. However, only a limited
amount of operating time remains, approximately 1 - 2 hours. The amount of time depends
on how often the LCD backlight is used and how often the unit is responding to alarm
conditions. Recharge the battery pack or replace the alkaline batteries as soon as possible
as described in “Replacing or Recharging the Batteries” on page 134.

NOTE: Alarms and the back light feature consume battery power and reduce the

amount of operating time remaining.

Responding to Sensor Failure Alarms

1. Determine which sensor has triggered the sensor failure alarm.

2. Try calibrating the sensor first, as described in “Calibration Mode” on page 56 before

replacing it.

3. If the sensor failure continues, replace the sensor as described in “Replacing a
Sensor” on page 142.

4. If the sensor failure condition continues after you have replaced the sensor, contact
for further instructions.

Responding to Clock Failure Alarm

This alarm occurs if the internal unit date has been changed to something unreasonable
like 15/34 (month/day).

1. Press and release the RESET SILENCE button to continue into normal operation.

CAUTION: There will be no datalogging function if you operate the instrument after a

clock failure.

2. Attempt to change the date using the DATE menu time in Maintenance Mode. See

“Updating the Date and Time Settings” on

3. If the date cannot be set correctly, contact as soon as possible.

page 95.

Responding to System Failure Alarms

1. If a system failure occurs, the system failure screen will display an error code as
shown below:

GX-2012 Operator’s Manual Measuring Mode, Alarms • 41

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2. The error code meanings are shown below:

Table 5: Error Code Explanation

Error Code Explanation

000 MPU failure
010 RAM failure
021 EEPROM failure
031 FLASH memory failure

3. If the error code is anything but 031 as shown above, the instrument cannot be used.
Contact as soon as possible.

If the error code is 031, you may press and release the RESET SILENCE button to
continue to normal oper

CAUTION: There will be no datalogging function if you operate the instrument after a

031 system failure. Contact as soon as possible.

ation if the instrument must be used temporarily.

Responding to Microprocessor Failure

If yo

ur unit experiences a microprocessor failure, the heart symbol at the top of the screen
will be steadily on or steadily off. The unit cannot be used in this case. Contact as soon
as possible.

Inert Mode

Inert Mode is used to measure the combustible gas and/or oxygen level in a purged
environment. In order for the instrument to operate in Inert Mode, the oxygen alarm must
be set to H-HH operation in which both alarms are increasing. The oxygen Warning and
Alarm points are factory set at 5.0% and 10.0%.

It is recommended that the %volume sensor be installed in a unit that is used to monitor
combustible gas during Inert Mode operation since it does not require oxygen to work
properly. The catalytic LEL sensor does not operate at oxygen concentrations below 10%
volume. If it is necessary to use the catalytic LEL sensor during Inert Mode operation, a
dilution fitting must be insta lled. Installing a dilutio n fitting will af fe ct the oxy gen re ading
since you’re introducing oxygen into the sample.

Alarms

The oxygen channel alarm points in Inert Mode are different from those in Normal Mode.
All other alarm point settings remain unchanged.

Since the application for Inert Mode is to detect a rising oxygen level in purged
environments, both oxygen alarms are set to rising. The factory set alarm point is 5.0%
volume for the Warning and 10.0% volume for the Alarm. These alarm points are user
adjustable in Maintenance Mode. See “Updating the Alarm Point Settings” on page 110
for instructions to set the alarm points.

42 • I n e r t M o d e GX-2012 Operator’s Manual

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Start Up and Operation

0

20.9
0

%LEL

%

ppm

CH4

O2

INERT

CO

1. With the oxygen alarm pattern set to H-HH, start up the GX-2012 as described in

“Turning On the GX-2012, Normal Mode Only” on page 23.

2. Once the warm up sequence is complete, the Normal Operation Screen will display

and INERT will appear along the bottom of the display.

3. Since the oxygen concentration in fresh air is above both oxygen alarm points, the

GX-2012 will go into alarm if turned on in a fresh air environment.

Display Mode

This section describes using the GX-2012 in Display Mode. W ith the GX-2012 in Display
Mode, you can:

• set the combustible gas channel range (pg. 44)

• display peak readings (pg. 44)

• display STEL and TWA readings (H2S and CO only) (pg. 45)

• display full scale, warning, alarm, STEL, and TWA (H2S and CO only) values (pg. 45)

• display time in operation (pg. 47)

• display the date and time (pg. 47)

• display remaining log time (pg. 48)

• clear the data logger (pg. 49)

• turn the pump on or off (pg. 50)

• select a user ID (pg. 51)

• select a station ID (pg. 52)

• display snap logging data (pg. 53)

• turn peak bar function on or off (pg. 54)
To enter Display Mode, press and release the DISPLA Y (ADJ) button while in Measuring

Mode. To scroll from one screen to the next press and release the DISPLAY (ADJ) button.
NOTE: Each screen displays for 20 seconds. If you do not press the DISPLAY (ADJ)

button to scroll to the next screen or press the POWER ENTER button to enter
an item within 20 seconds, the GX-2012 automatically returns to Measuring
Mode.

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HC Range Screen

HC
SEL

22:39

HC RANGE

0

20.9
0

0.0

%LEL

%

ppm

ppm

CH4

O2

PEAK

CO
H2S

PEAK

This screen displays only if your GX-2012 is equipped with both the catalytic % LEL
combustible sensor and the TC % volume combustible sensor. It allows you to select the

display units for the combustible channel as % LEL/% volume autoranging or % volume.
If autoranging is selected, the combustible gas reading will be displayed in % LEL up to
100% LEL, which is equivalent to 5% volume for methane (CH4). Above 100% LEL, it

will be displayed in %volume. If % volume is selected, the combustible gas reading will
be displayed in % volume only.

CAUTION: If the combustible channel is set for % volume only, then there are no gas

alarms for any detection channel and NO ALARM will appear in the upper
left corner of the screen when you return to normal operation.

To update the HC range setting:

1. After entering Display Mode and arriving at the HC Range Screen, press and release

the POWER ENTER button. The current setting will appear at the bottom of the
LCD.

2. Use the AIR or (SHIFT) button to change the setting.

3. Press the POWER ENTER button to save the change.

4. Press the DISPLAY (ADJ) button to advance to the next screen.

Peak Screen

The Peak Screen displays the highest (lowest for O2) concentrations detected since the
GX-2012 was turned on. Peak readings are stored in the GX-2012’s memory until a higher

level is detected, the peak reading is reset, or the GX-2012 is turned off.
The lunch break feature enables the GX-2012 to remember peak readings when it is turned

off so it can continue them when it is turned on again. See “Turning On the GX-2012,
Normal Mode Only” on page 23. To reset the peak readings during operation, press and
hold the RESET SILENCE button for a few seconds while in the peak screen.

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STEL Screen

0

0.0

ppm

ppm

STEL

CO
H2S

0

0.0

ppm

ppm

TWA

CO
H2S

dISP

ALARM--P

The STEL Screen displays the short-term exposure limit (STEL) readings for CO and H2S
only. The STEL reading is the average reading during the last 15 minutes.

TWA Screen

The TWA Screen displays the time-weighted average (TWA) readings for CO and H2S
only.

The TWA reading is the average reading during the last 8 hours. If 8 hours have not
elapsed since the last time the TWA reading was cleared, the average is still calculated
over 8 hours. The missing time is assigned a 0 value for readings.

Alarm Points Screen

The Alarm Points Screen allows you to view each channel’s alarm settings for full scale,
warning, alarm, STEL (for CO and H2S only), and TWA (for CO and H2S only). The

bottom line of the screen will alternate between ALARM--P, NO /DISP, and YES/ENT.

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Press the POWER ENTER button to proceed to view the full scale settings. Use the

100

40.0
500

100.0

vol%
%LEL

%

ppm

ppm

CH4

O2

F. S.

CO
H2S

10

19.5
25

5.0

%LEL

%

ppm

ppm

CH4

O2

WARNING

CO
H2S

50

23.5
50

30.0

%LEL

%

ppm

ppm

CH4

O2

ALARM

CO
H2S

200

15.0

ppm

ppm

STEL

CO
H2S

AIR or (SHIFT) buttons to scroll through screens showing the different settings.

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Pressing and releasing POWER ENTER while in a settings screen will cause the

25

10.0

ppm

ppm

TWA

CO

H2

S

0:11

OP. TIME

2011
8
31
22:39

DATE

instrument to simulate that condition. The buzzer, LEDs, and vibration will activate. Press
and release POWER ENTER again to stop the simulated alarm.

Operation Time Screen

The operation time screen displays the time in minutes since the GX-2012 was last turned
on. The operation time may be continued from the last time the GX-2012 was in operation
by using the lunch break option. See “Turning On the GX-2012, Normal Mode Only” on
page 23.

Date/Time Screen

The date/time screen displays the current date and time with the order being year, month,
day, time.

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Remaining Log Time Screen

LOG
276

H

REMAIN

The remaining log time screen displays the time remaining until the data logger memory is
full. The remaining log time depends on how often the GX-2012 stores data to the data
log, how many channels are active, and how often the GX-2012 is turned on and off.

The table below illustrates how much data logging time is available for the various
interval times. It assumes that the unit is set up with all 5 sensors and there are no alarm
occurrences.

Table 6: Data Logging Capacity, 5 Sensor GX-2012

Interval

Time

10 seconds 10 hours
20 seconds 20 hours
30 seconds 30 hours

1 minute 60 hours
3 minutes 180 hours
5 minutes 300 hours

10 minutes 600 hours

Data Logging Time

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Clear Data Logger Screens

CLr

LG CLEAR

LOG

CLr

CONFIRM?

LOG

CAUTION: Once you clear the data logger, you cannot retrieve any data previously

stored in the data logger.

NOTE: This item appears in Display Mode only if the DLOG DSP menu item in

Maintenance Mode is turned ON. The factory setting for DLOG DSP is ON.

The clear data logger screens allow you to clear the data logger storage. You can set the
GX-2012 to overwrite the oldest data when the data log is full. See “Updating the Datalog
Overwrite Setting” on page 118. The bottom line of the screen alternates between LG
CLEAR, NO /DISP, and YES/ENT.

To clear the data log:

1. With the above screen displayed, press and release the POWER ENTER button.

The instrument will ask you to confirm that you want to clear the data log and CLr
LOG will be flashing. The bottom line of the screen alternates between CONFIRM?,
YES/ENT., AND NO /DISP.

2. To cancel the clear data log and return to the Clear Data Logger Screen in Display
Mode, press and release DISPLAY (ADJ).

To continue with the clear data log, press and release POWER ENTER.

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3. The GX-2012 displays 4 dashes and as the GX-2012 clears the data, the dashes

LG CLEAR

- - - -

On

PUMP OFF

disappear. When the last dash is gone, the GX-2012 has been cleared and the
remaining log time value is reset.

Pump OFF Screen

WARNING: The GX-2012 is not a gas monitoring device while the pump is off.

NOTE: This item appears in Display Mode only if the POFF DSP menu item in

Maintenance Mode is turned ON. The factory setting for POFF DSP is OFF.

The GX-2012 pump can be turned on and of f in thi s s creen. The bottom li ne of t his screen
alternates between PUMP OFF, NO /DISP, and YES/ENT. This feature can be used to
conserve battery life if there is a significant period of time until the next gas monitoring
task, but you do not want to wait for the warmup sequence to complete if you turn the
instrument off and on again.

In this screen, press POWER ENTER to turn the pump off. The fan in the upper right
corner of the screen will disappear. Once the pump is off, you cannot exit this screen and
return to normal operation or continue in Display Mode until you turn the pump back on.
To turn the pump back on and continue in Display Mode or return to Normal Operation,
press the POWER ENTER button again.

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User ID Screen

U Id

YES/ENT.

SEL

U Id

USER--001

SEL

This screen always appears in Display Mode, regardless of the ID DISP setting in the
Maintenance Mode menu. Each user ID can contain up to 16 characters but only the first 8
of those characters are visible in the instrument. Be sure that all user IDs are
distinguishable from each other by viewing only the first 8 characters. For more
information, see the GX-2012 Data Logger Management Program manual. The bottom
line of the screen alternates between YES/ENT., the current user ID, and NO /DISP.
Uppercase letters, numbers, asterisks (*), dashes (-), and a blank space are available
characters. The GX-2012 can store 128 user IDs.

Use this screen to identify or change the user. The user ID provides a way to identify the
user during a data logging session. The user ID is saved to the data logger for that session
when you turn off the GX-2012 or change users during operation. This allows you to
change the user ID during operation and have each user ID that was used during an
operating session saved for the corresponding data.

NOTE: As shipped from the factory, the user ID on this screen is shown as

-- -- -- -- -- -- until you enter this screen and select a user ID.

To change a user:

1. After entering Display Mode and proceeding to the User ID screen, press and release
the POWER ENTER button. The bottom line of this screen alternates between YES/
ENT., the current user ID, and NO /DISP.

2. Use the AIR and (SHIFT) buttons to scroll through the 128 possible user IDs.

3. Press the POWER ENTER button to select a user ID.

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Station ID Screen

S Id

YES/ENT.

SEL

S Id

001

SEL

This screen always appears in Display Mode, regardless of the ID DISP setting in the
Maintenance Mode menu. Each station ID can contain up to 16 characters but only the
first 8 of those characters are visible in the instrument. Be sure that all station IDs are
distinguishable from each other by viewing only the first 8 characters. For more
information, see the GX-2012 Data Logger Management Program manual. The bottom
line of the screen alternates between YES/ENT., the current station ID, and NO /DISP.
Uppercase letters, numbers, asterisks (*), dashes (-), and a blank space are available
characters. The GX-2012 can store 128 station IDs.

Use this screen to identify or change the station. The station ID provides a way to identify
the station during a data logging session. The station ID is saved to the data logger for that
session when you turn off the GX-2012 or change stations during operation. This allows
you to change the station ID during operation and have each station ID that was used
during an operating session saved for the corresponding data.

NOTE: As shipped from the factory, the station ID on this screen is shown as

-- -- -- -- -- -- until you enter this screen and select a station ID.

To change a station:

1. After entering Display Mode and proceeding to the Station ID screen, press and hold
the POWER ENTER button. The bottom line of this screen alternates between YES/
ENT., the current station ID, and NO /DISP.

2. Use the AIR and (SHIFT) buttons to scroll through the 128 possible station IDs.

3. Press the POWER ENTER button to select a station ID.

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Snap Logging Screen

d ISP

REC. DATA

NO DATA

2011
8
31
22:39

M023

The Snap Logging Screen allows you to view data from previous snap loggings. For
information on how to use the snap logging feature, see “Snap Log Mode” on page 34.

1. To view snap logging data, use the AIR and (SHIFT) buttons to scroll to the
Snap Logging Screen. The bottom line of this screen alternates between REC. DATA,
NO /DISP, and YES/ENT.

2. Press and release the POWER ENTER button. If no snap logs have been performed,
the following screen will appear.

3. If snap logs have been performed, the following screen will appear.

This screen indicates the year, month, day , and time that the most recent snap log was
taken. The number along the bottom of the screen indicates the snap log ID number.
The first snap log that is taken is given an ID of M001. The next snap log ID is M002.
The ID number increases sequentially with each set of snap log data. Use the AIR
and (SHIFT) buttons to scroll through different snap log IDs and view what time
they were taken.

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4. To view the data in a snap log ID, press and release the POWER ENTER button.

50

23.5
50

30.0

%LEL

%

ppm

ppm

CH4

O2

001

CO

H2

S

bAr
SEL

BAR OFF

bAr
SEL

BAR ON

The gas readings that were taken during the snap log are displayed and the Station ID
that was in use during the snap log is displayed along the bottom of the screen. You
can use the AIR and (SHIFT) buttons to scroll through the different snap logs.
The gas readings and station ID will change but the snap log ID is not visible from
this screen. To scroll through the data by viewing the snap log ID number,
press and release POWER ENTER.

Peak Bar Select Screen

The Peak Bar Select Screen allows you to turn the peak bar on or off. If the function is
turned on, the peak bar appears along the left side of the screen during Normal Operation
and on the Peak Screen in Display Mode. It shows the peak readings for each channel in
bar graph format. The bottom line of this screen alternates between the current setting, NO
/DISP, and YES/ENT.

To adjust the peak bar selection:

1. Use the DISPLAY (ADJ) button to scroll to the Peak Bar Select Screen. The screen
indicates the current setting.

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2. Press and release the POWER ENTER button.

On

PEAK BAR

3. Use the AIR and (SHIFT) buttons to make your selection and press and release
the POWER ENTER button.

Data Logging

NOTE: The GX-2012 logs data in both Normal Mode and Bar Hole Mode.
The GX-2012 fea

computer via the infrared communications port located just below the RESET SILENCE
button. It logs gas readings during normal operation, alarm data, and calibration data.

NOTE: The data logging function is separate from the snap logging function. For a

To utilize the GX-2012’s downloading capability, you will need the GX-2012
downloading software and a computer with an infrared port or a USB port that runs one of
the following operating systems: Windows 7, Windows 8, or Windows 10. If your
computer has an infrared port, then no additional accessories are needed to download data
from the GX-2012. If your computer does not have an infrared port but does have a USB
port, a USB/IrDA adapter cable can be used to download data from the GX-2012 using a
USB port. The USB/IrDA adapter cable is also available from RKI.

For a complete description of the downloading software and procedures for downloading
data to a computer, see the GX-2012 Data Logger Management Program Operator’s
Manual.

SDM-2012

The GX-2012 can be used with the SDM-2012 if desired. The SDM-2012 can charge the
instrument if the lithium ion battery pack is being used. It can also bump test, calibrate,
and retrieve saved data. The SDM-2012 can be operated as a single, stand-alone unit or
can be used with up to 9 other SDM-2012s and operated using a computer. For more
information about the operation of the SDM-2012, see the SDM-2012 operator’s manual.

tures the ability to log data to its internal memory and download it to a

description of the snap logging function, see “Snap Log Mode” on page 34.

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Calibration Mode

Calibration Mode allows you to calibrate the GX-2012’s sensor response and to bump test
the GX-2012.

The unit should be calibrated periodically. The optimum frequency of calibration depends
heavily on how the GX-2012 is used. For example, instruments used daily may need to be
calibrated weekly or monthly, while instrume nts that are used onl y a few times a yea r may
need to be calibrated before each use. Typical calibration frequencies range from monthly
to quarterly.

You can program the GX-2012 to notify you when it is due for calibration. See “Updating
the Calibration Reminder Setting” on page 119.

Calibration/Bump Test Supplies and Equipment

To calibrate or bump test the GX-2012, you will need:

• Known calibrating samples of the gases being detected. The combustible and toxic gas

samples should have concentrations in approximately the middle of the range of
detection. An oxygen-free source, such as 100% nitrogen is recommended for setting
the oxygen zero when using single calibration.

• A demand-flow regulator to provide adequate sample gas flow

• Non-absorbent tubing

CAUTION: If you are using a calibration kit that includes a gas bag and a fixed flow

regulator or dispensing valve, do not apply gas directly to the GX-2012
with the regulator or valve or damage to the pump will result. See
“Appendix A: Calibrating and Bump Testing with a Sample Bag” on
page 148 for instructions to properly use a gas bag kit.

To calibrate or bump test the %LEL, Oxygen, CO, and H2S sensors at the same time,
automatically, with no need for a zero-oxygen source, you can use the auto calibration

feature with a 4-gas cylinder. If t he H2S channel is not active, then a 3-gas cylinder may be
used for auto-calibration. This section includes instructions for auto calibration and bump

testing with a demand-flow regulator, a 4-gas cylinder, and a %volume methane cylinder.
This section also includes instructions for calibrating one channel at a time using single
calibration.

NOTE: If the combustible gas channel(s) are calibrated to a gas other than

methane, use an appropriate multigas cylinder or use single calibration
to calibrate the combustible channel(s).

Preparing for Calibration or Bump Testing

Whether you will calibrate the GX-2012 using auto calibration, single calibration, or
perform a bump test, you will need to set the fresh air readings first.

1. Find a fresh-air environment. This is an environment free of toxic or combustible
gases and of normal oxygen content (20.9%).

2. Turn on the unit as described in “Turning On the GX-2012, Normal Mode Only” on
page 23 or in “Turning On the GX-2012 in Normal Mode With All Modes Active” on
page 28. Use the sample hose and probe.

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3. With the unit on, perform a fresh air adjustment by pressing and holding the AIR

Err

PASSWORD

MAINTENANCE

AIR CAL

button. The display prompts you to hold the AIR button.

4. Continue to hold the AIR button until the display prompts you to release it. The
GX-2012 will set the fresh air reading for all channels as it counts down from 8. If the
combustible channel is set as %LEL only or vol% only, there is no countdown period.
The fresh air reading is set immediately.

5. Install the demand flow regulator onto the calibration cylinder.

6. Connect the sample tubing to the demand flow regulator.

Calibrating the GX-2012

From Measuring Mode, enter Calibration Mode by pressing and holding the (SHIFT)
button, then pressing the DISPLAY(ADJ) button and releasing both. If the unit prompts
you for the password, enter it by using the AIR and (SHIFT) buttons to select each
password number and then pressing and releasing POWER ENTER to confirm it and
move on to the next number. To go back a number, press and release the RESET
SILENCE button. The factory set password is the same as the factory set password for
Maintenance Mode: 2102. You can change the password by entering the PASSWORD
menu item in Maintenance Mode. See “Turning the Password Function On or Off” on
page 128. If you enter an incorrect password, an error screen will display.

To return to normal operation, press and release the RESET SILENCE button. You may
then try to reenter Calibration Mode.

MAINTENANCE will appear along the top of the screen once you have entered
Calibration Mode. The first item in the calibration menu, AIR CAL, displays.

NOTE: The following screens illustrate a four-gas GX-2012 with both a %LEL and a

%volume combustible gas sensor as examples only. Your GX-2012 may display
slightly different screens.

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The GX-2012’s calibration menu includes two methods of calibration:

50

12.0
50

25.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

AUTO CAL

CO
H2S

100

vol%

MAINTENANCE

CH4

AUTO CAL

auto calibration and single calibration.

• Auto Calibration: This method allows you to calibrate the combustible gas (%LEL

sensor only), OXY, H2S, and CO sensors simultaneously. It is designed for use with
the RKI 4-gas calibration cylinder and is the quickest and easiest method to calibrate

the GX-2012. If installed, you may also calibrate the %volume sensor separately from
the standard four.

• Single Calibration: This method allows you to calibrate one sensor at a time. Use this

method if you are only calibrating one or two sensors, if you are calibrating only the
%volume combustible sensor, or if you are not using the RKI 4-gas calibration
cylinder.

Calibrating with the Auto Calibration Method

This section describes calibration using the auto calibration method.
To calibrate using the single calibration method, see “Calibrating with the Single
Calibration Method” on page 60. These instructions assume you are using a 4-gas cylinder
and a %volume methane cylinder.

NOTE: If the combustible gas channel(s) are calibrated to a gas other than

methane, use an appropriate multigas cylinder or use single calibration
to calibrate the combustible channel(s).

1. You may only calibrate either the standard 4 sensors or the % volume combustible
sensor at a time. Once you are finished, you are returned to the initial AUTO CAL
screen and must begin the auto calibration process again.

2. Use the AIR and (SHIFT) buttons to display the AUTO CAL menu item, press
and release the POWER ENTER button to display the calibration values screen. If
you want to exit back to the main menu without completing a calibration, press and
release the DISPLAY (ADJ) button.

3. Use the AIR or (SHIFT) button to alternate between the 4-gas and the % volume
combustible gas calibration values screens.

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4. The gas concentrations displayed in the calibration values screens must match the gas

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concentrations listed on the calibration cylinders. If all concentrations match, go to

- - -

%LEL

MAINTENANCE

CH4

AUTO CAL

0

20.9
0

0.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

AUTO CAL

CO
H2S

step 12. If one or more concentrations do not match, continue with step 5.

5. To adjust the values on the screens, hold down the (SHIFT) button, then press the
DISPLAY(ADJ) button and release both. The %LEL sensor is shown here.

6. Use the AIR and (SHIFT) buttons to scroll through the sensors and select the
sensor whose calibration gas value you want to adjust.

7. Press and release the POWER ENTER button. The sensor’s calibration gas value will
flash.

8. If necessary, use the AIR and (SHIFT) buttons to set the correct calibration gas
value.

9. Press and release POWER ENTER button to save the change.

10. Repeat steps 6 through 9 to set the correct values for any additional sensors.

11. After the last calibration gas value is set, use the AIR button to scroll to ESCAPE
and press POWER ENTER to return to the calibration gas values screens.

NOTE: The RKI Four Gas Cylinder typically contains 12% O2 by volume. Be sure to

set the “OXY” reading to agree with the concentration listed on the cylinder’s
label, not zero.

12. Use the AIR or (SHIFT) button to select which sensor(s) you want to calibrate,
the standard 4 sensors or the %volume combustible gas sensor.

The following instructions illustrate calibrating the standard 4 sensors first, then the
%volume combustible gas sensor.

13. W ith the 4-gas calibration values screen displayed, press the POWER ENTER button.
AUTO CAL begins to flash and the current gas readings are displayed. If you want to
exit back to the main menu without completing a calibration, press and release the
DISPLAY (ADJ) button.

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GX-2012 Operator’s Manual Calibration Mode • 59

14. Connect the tubing from the demand flow regulator to the rigid tube on the probe.
Allow the gas to flow for one minute.

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15. Press and release the POWER ENTER button to set the calibration to the

%

ppm

MAINTENANCE

O2

FAIL

H2S

programmed values.
If all channels passed calibration, P AS S displays along the bottom of the screen, then

the calibration menu displays.
If any of the sensors cannot calibrate to the proper value, FAIL displays along the

bottom of the screen and the GX-2012 lists the sensor(s) that failed to calibrate. In the
example below, the OXY and H2S channels failed calibration. The other sensors

calibrated normally.

The buzzer and alarm lights activate. Press and release the RESET SILENCE button
after the buzzer and lights stop to reset the alarm and return to the calibration menu.
Attempt to calibrate again. If the failure continues, investigate the cause. See
“Troubleshooting” on page 131.

16. Disconnect the tubing from the probe.

17. Unscrew the demand flow regulator from the calibration cylinder.

18. If you have a 5 sensor unit and wish to calibrate the %volume combustible gas sensor ,
go back to step 1 and repeat the process selecting the %volume calibration gas value
screen in step 12 and using a %volume methane cylinder.

If you are finished calibrating, use the (SHIFT) button to navigate to the
NORMAL menu item, then press and release the POWER ENTER button to return to
Measuring Mode.

Calibrating with the Single Calibration Method

This section describes calibration using the Single Calibration method.
To calibrate using the Auto Calibration method, see “Calibrating with the Auto
Calibration Method” on page 58.

The procedure below describes a span adjustment of one channel using a calibration kit
that includes a 4-gas calibration cylinder, a 0.5 LPM (liters per minute) regulator , and non­absorbent sample tubing. The standard 4-gas cylinder consists of 50% LEL methane, 12%
oxygen, 50 ppm CO, 25 ppm H

CH4 channel’s span is adjusted. See “Chapter 8: Parts List” on page 145 for available
calibration kits and calibration kit spare parts.

S, and a balance of nitrogen. In the example below, the

2

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Calibration cylinders that contain only one target gas may also be used for single

MAINTENANCE

ONE CAL

- - -

%LEL

MAINTENANCE

CH4

ONE CAL

- - -

vol%

MAINTENANCE

CH4

ONE CAL

calibration. For channels other than oxygen, RKI Instruments, Inc. recommends that you
use a cylinder that contains a concentration of 10-50% of the full scale value of the target
gas. For example, if you are calibrating the combustible gas channel, your calibration
cylinder should have a combustible gas concentration between 10% LEL and 50% LEL.
For the oxygen channel, RKI Instruments, Inc. recommends using 100% nitrogen to
perform the adjustment but any concentration between 0% oxygen (100% nitrogen) and
17% oxygen can be used to make the adjustment.

NOTE: If your combustible gas channel is calibrated to a gas other than

methane, use an appropriate gas cylinder to perform the calibration.

CAUTION: The single calibration method does not have a “FAIL” notification. If a

sensor cannot be set to agree with the calibration source, see
“Troubleshooting” on page 131.

1. While in the calibration menu, use the AIR or (SHIFT) button to navigate to the
ONE CAL menu option.

2. Press and release the POWER ENTER button to display the single calibration menu.
The %LEL sensor will be displayed first.

3. Use the AIR or (SHIFT) button to display the sensor you want to calibrate (in
this example the combustible gas % LEL sensor). If you have a 5 sensor unit, the
%vol sensor will be one of the choices. It is shown below.

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4. Press and release the POWER ENTER button. The single calibration screen displays

0

%LEL

MAINTENANCE

CH4

ONE CAL

- - -

%LEL

MAINTENANCE

CH4

ONE CAL

for the sensor you selected. The gas reading flashes.

5. Connect the tubing from the demand flow regulator to the rigid tube on the probe.
Allow the calibration gas to flow for one minute.

6. If necessary, use the AIR and (SHIFT) buttons to adjust the reading to match the
concentration listed on the calibration cylinder.

If the reading already matches the concentration listed on the calibration cylinder,
press and release the AIR button then press and release the (SHIFT) button so
that the instrument sees a change and resets the calibration date.

7. Press and release the POWER ENTER button to save the span value. The LCD will
indicate that the calibration has ended, then the single calibration menu displays.

8. Disconnect the tubing from the probe.

9. Repeat steps 3 through 8 for any other sensors you want to calibrate. Make sure you
use an appropriate calibration cylinder for each sensor.

CAUTION: When calibrating the oxygen channel, verify the concentration of oxygen

listed on the cylinder’s label. For oxygen-free samples (100% nitrogen for
example), set the oxygen zero setting to 0.0%.

10. After the last channel is calibrated, disconnect the calibration tubing from the probe,
then unscrew the demand flow regulator from the calibration cylinder.

11. Use the AIR and (SHIFT) buttons to scroll to ESCAPE in the ONE CAL menu.

12. Press and release the POWER ENTER button to exit ONE CAL.

13. With the ONE CAL menu option displayed, press the (SHIFT) button until the
NORMAL menu option is displayed.

14. Press and release the POWER ENTER button to return to Measuring Mode.

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Bump Testing the GX-2012

Err

PASSWORD

MAINTENANCE

BUMP

NOTE: The BUMP DSP menu item in Maintenance Mode is factory set to OFF. The

BUMP menu item will not appear unless BUMP DSP is set to ON. See

“Turning the Bump Test Function On or Off” on page 115 for instructions.

NOTE: The GX-2012 uses parameters defined in the BUMP--SET menu item of

Maintenance Mode while performing a bump test. To view or update these
parameters, see “Updating the Bump Test Parameters” on page 116.

NOTE: If the combustible gas channel(s) are calibrated to a gas other than

methane, use an appropriate multigas cylinder.

From Measuring Mode, enter Calibration Mode by pressing and holding the (SHIFT)
button, then pressing the DISPLAY(ADJ) button and releasing both. If the unit prompts
you for the password, enter it by using the AIR and (SHIFT) buttons to select each
password number and then pressing and releasing POWER ENTER to confirm it and
move on to the next number. To go back a number, press and release the RESET
SILENCE button. The factory set password is the same as the factory set password for
Maintenance Mode: 2102. You can change the password by entering the PASSWORD
menu item in Maintenance Mode. See “Turning the Password Function On or Off” on
page 128. If you enter an incorrect password, an error screen will display.

To return to normal operation, press and release the RESET SILENCE button. You may
then try to reenter Calibration Mode.

MAINTENANCE will appear along the top of the screen once you have entered
Calibration Mode. The first item in the calibration menu, AIR CAL, displays.

1. Install the demand flow regulator onto the calibration cylinder.

2. Connect the sample tubing to the demand flow regulator.

3. Install the hose and probe to the GX-2012.

4. Use the AIR or (SHIFT) buttons to display the BUMP menu item.

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5. Press and release the POWER ENTER button to display the bump test gas values.

50

12.0
50

25.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

BUMP 30

CO

H2

S

100

vol%

MAINTENANCE

CH4

BUMP 30

F
P
F
P

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

BUMP

CO
H2S

6. Use the AIR or (SHIFT) buttons to see the %volume combustible gas bump test
value.

7. A bump test may be performed on the standard 4 sensors or on the %volume
combustible sensor . Use t he AIR or (SHIFT) buttons to display the screen for the
sensor(s) you wish to bump test.

8. Before proceeding, confirm that the bump test gas value(s) are the same as the
concentration(s) in the calibration cylinder. If they are not, adjust the bump test gas
value(s) by entering the AUTO CAL menu item, changing the values there, and
reentering the BUMP menu.

9. Connect the tubing from the demand flow regulator to the rigid tube on the probe then
quickly press and release the POWER ENTER button. The unit will begin counting
down from 30.

When Bump Test Passes or Fails and AUTO CAL is OFF

a. If the AUTO CAL menu item in BUMP-SET is OFF, the instrument will

indicate which channels passed or failed the bump test with a P (pass) or an F
(fail) to the right of the gas.

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b. To view the bump test gas readings press the AIR or (SHIFT) button. You

5

12.0
10

25.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

BUMP

CO
H2S

F
P
F
P

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

BUMP

CO
H2S

5

12.0
10

25.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

BUMP

CO
H2S

MAINTENANCE

BUMP

can scroll between the bump test results and the bump test gas readings with
the AIR or (SHIFT) button.

c. The instrument will indicate which channels passed or failed the bump test

with a P (pass) or an F (fail) to the right of the gas.

d. To view the bump test gas readings press the AIR or (SHIFT) button. You

can scroll between the bump test results and the bump test gas readings with
the AIR or (SHIFT) button.

e. To return to the BUMP screen in Calibration Mode, press POWER ENTER.

If one or more sensors fail the bump test, see “Troubleshooting” on page 131 to
investigate the cause of the failure and replace the failed sensor or sensors if
necessary.

f. Disconnect the tubing from the probe.

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When Bump Test Passes and AUTO CAL is ON

P
P
P
P

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

BUMP

CO
H2S

45

12.0
47

23.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

BUMP

CO
H2S

MAINTENANCE

BUMP

a. If the AUTO CAL menu item is set to ON in the BUMP--SET menu and all

channels pass the bump test, the following screen appears:

b. To view the bump test gas readings press the AIR or (SHIFT) button. You

can scroll between the bump test results and the bump test gas readings with
the AIR or (SHIFT) buttons.

c. To return to the BUMP screen in Calibration Mode, press POWER ENTER.

d. Disconnect the tubing from the probe.

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When Bump Test Fails and AUTO CAL is ON

1

20.9
37

10.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

CAL 60

CO
H2S

FP
PP
FF
PP

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

BUMP/CAL

CO
H2S

1

12.0
5

23.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

BUMP/

CO
H2S

a. If the AUTO CAL menu item is set to ON in the BUMP--SET menu and any

channel fails the bump test, the instrument will beep and a calibration is
immediately and automatically started.

b. Continue to apply the calibration gas. CAL on the bottom left of the screen will

alternate with APPLY.

c. The calibration time will begin to countdown in seconds in the lower right of

the screen. The calibration time counted down during a calibration initiated
because of a failed bump test is the difference between the bump test gas time
and the calibration time defined in the BUMP--SET menu item in
Maintenance Mode.

d. At the end of the calibration, the instrument displays the results from both the

bump test and the calibration. Use the AIR or (SHIFT) button to scroll
between the calibration/bump test results, the bump test gas readings, and the
calibration gas readings.

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e. To return to the BUMP screen in Calibration Mode, press POWER ENTER at

49

12.0
5

25.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

/CAL

CO

H2

S

MAINTENANCE

BUMP

any time. If any channel failed the calibration, the buzzer will sound a double
pulsing tone until you press and release the POWER ENTER button.

f. Disconnect the tubing from the probe.

10. Unscrew the demand flow regulator from the calibration cylinder.

11. With the BUMP menu option displayed, press the (SHIFT) button until the
NORMAL menu option is displayed.

12. Press and release the POWER ENTER button to return to Measuring Mode.

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Chapter 4: Using the GX-2012 in Bar Hole Mode

0

20.9
0

0.0

vol%
%LEL

%

ppm

ppm

CH4

O2

NORMAL ?

CO
H2S

Overview

This chapter explains how to operate the GX-2012 in Bar Hole Mode. Bar Hole Mode is
used to perform consistent checks of bar holes when tracking down underground gas
leaks. When the GX-2012 is in Bar Hole Mode, only the combustible and oxygen
channels are disp la yed.

If a GX-2012 is intended for bar hole testing, it is shipped with Bar Hole Mode enabled so
that the operator must choose which operational mode to use when the unit is turned on.

NOTE: Units intended for bar hole testing are typically calibrated to methane. In

addition, the unit must have a %volume combustible sensor installed.

Start Up, Bar Hole Mode

This section explains how to start up the GX-2012 in Bar Hole Mode and get it ready for
operation.

Turning On the GX-2012, Bar Hole Mode

WARNING: If a CO or H2S sensor is installed, th es e sen sors will not be activ e wh ile

the GX-2012 is in Bar Hole Mode.

WARNING: Gas alarms are not active when the GX-2012 is in Bar Hole Mode.

The following description of the GX-2012 start up sequence assumes that the following
menu items in Maintenance Mode are turned on: LNCH BRK, ID DISP, CL RMNDR,
and BP RMNDR. If either of these items is turned off, then the corresponding screen will
not appear.

NOTE: In order for BAR HOLE MODE to appear as a selection in the Mode Select

Screen in Step 3 below, the L./B. MODE menu item in Maintenance Mode
must be set to bH or LC bH.

1. Connect the sample hose to the GX-2012’s quick connect inlet fitting.

2. Screw the bar hole probe onto the sample hose’s threaded fitting.

3. Press and briefly hold down the POWER ENTER button. The Normal Mode Select
Screen displays.

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4. Use the AIR or (SHIFT) buttons to scroll to the Bar Hole Mode Select Screen.

0

20.9
30

vol%
%LEL
ppm

%

BAR HOLE MODE

vol%

sec

CH4

O2

B.H. MODE?

CAL

C--LIMIT

FAIL

C--LIMIT

5. With the Bar Hole Mode Select Screen displayed, press and release the POWER
ENTER button to begin the Bar Hole Mode startup sequence.

NOTE: If no button is pressed for 20 seconds, the unit will proceed into whichever

mode is displayed.

6. If CL RMNDR is turned on (factory setting), the screen that appears next depends on
how CL EXPRD is set in the Maintenance Mode Menu ((pg. 119)).

• If the unit is due for calibration and CL EXPRD is set to CONFIRM (factory

setting), then the following screen displays.

The alarm LED’s and buzzer will pulse several times. After this, press and
release the RESET SILENCE button to continue.

• If the unit is due for calibration and CL EXPRD is set to NOT USE, then the

following screen displays.

The GX-2012 cannot be used until a calibration has been performed either by
selecting AUTO CAL or ONE CAL in the Maintenance Mode menu. See
“Calibrating Using Auto Calibration” on page 97 or “Calibrating Using Single
Calibration” on page 100 for calibration instructions.

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• If calibration is not due or CL EXPRD is set to NO EFFECT, then the following

2011
9
30
69d

NEXT CAL

tESt

B--LIMIT

FAIL

B--LIMIT

screen appears for a few seconds indicating when the next calibration is due.

7. If BP RMNDR is turned on (factory setting is OFF), the screen that appears next
depends on how BP EXPRD is set in the Maintenance Mode Menu ((pg. 119)).

• If the unit is due for a bump test and BP EXPRD is set to CONFIRM (factory

setting), then the following screen displays.

The alarm LED’s and buzzer will pulse several times. After this, press the
RESET SILENCE button until you hear a beep to continue.

• If the unit is due for a bump test and BP EXPRD is set to NOT USE, then the

following screen displays.

The GX-2012 cannot be used until a bump test has been performed by selecting
BUMP in the Maintenance Mode menu. See “Performing a Bump Test” on
page 102 for bump testing instructions.

GX-2012 Operator’s Manual Start Up, Bar Hole Mode • 71

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• If a bump test is not due or BP EXPRD is set to NO EFFECT, then the following

2011
9
30
10d

NEXTBUMP

U Id

- - - - - - - -

S Id

- - - - - - - -

2011
8
31
22:39

DATE

screen appears for a few seconds indicating when the next bump test is due.

NOTE: If both CL RMNDR and BP RMNDR are turned off, a WARM UP screen will

display before the warm up sequence continues.

8. If ID DISP is turned on (see (pg. 123)), the User ID Screen displays for a few seconds
and then the Station ID Screen displays for a few seconds.

9. The Date/Time Screen appears for a few seconds.

This screen displays the current year, month, date, and time.

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10. The Battery Level and Alarm Pattern Screen appears next.

bAtt

3.7

AL-H V

bAtt

3.7

AL-H D: V

AL -- H indicates latching (hold) alarms and AL -- A indicates self-resetting
(automatic) alarms. The number shown indicates the voltage of the batteries. A fully
charged lithium ion battery pack will display 3.7 V. If the unit is powered by alkaline
(dry cell) batteries, a “D” will appear in front of the “V” in the lower right corner.

11. The display then indicates the following items for about a second each:

• Full scale values for all channels

• Warning setpoint (low gas alarm) for all channels

• Alarm setpoint (high gas alarm) for all channels

• STEL alarm setpoint for the CO and H2S channels

• TWA alarm setpoint for the CO and H2S channels

GX-2012 Operator’s Manual Start Up, Bar Hole Mode • 73

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12. If the GX-2012 experiences a sensor failure during start up, a screen indicating which

FAIL

vol%

CH4

SENSOR

0

20.9

%LEL

%

BAR HOLE MODE

CH4

O2

001

sensor failed displays. In the example below, the combustible gas %volume sensor
has failed.

If one of the combustible sensors, LEL or % volume, fails, it is not possible to enter
Bar Hole Mode. Press and release the RESET SILENCE button to acknowledge the
failure and return to the Mode Select Screen. Replace the failed sensor as soon as
possible.

If the oxygen sensor fails, press and release the RESET SILENCE button to
acknowledge the failure and continue to Bar Hole Mode. The gas reading for the
oxygen sensor will be replaced by “XXX”. Replace the failed sensor as soon as
possible.

If the CO or H2S sensor is installed and fails, press and release the RESET SILENCE
button to acknowledge the failure and continue to Bar Hole Mode.

13. The GX-2012 is now operating in Bar Hole M ode. The pum p is of f and the foll owing
screen appears.

The methane and oxygen channels are displayed along with the battery charge level.

Performing a Fresh Air Adjustment, Bar Hole Mode

Before using the GX-2012, it is recommended to set the fresh air readings for the target
gases by performing a fresh air adjustment. This will set the combustible gas channel to
zero and the OXY channel to 20.9%.

1. Find a fresh-air environment. This is an environment free of toxic or combustible
gases and of normal oxygen content (20.9%).

2. Turn on the unit as described above in “Turning On the GX-2012, Bar Hole Mode”.

3. Press and hold the AIR button. The pump will start and the display will prompt you
to hold the AIR button.

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4. Continue to hold the AIR button until the displ ay prompts you to release the AIR

S Id

001

SEL

0

0.0

%LEL

%

BAR HOLE MODE

CH4

O2

001

button. The GX-2012 will set the fresh air reading for the CH4 and oxygen channels
as it counts down from 8. Once the countdown has finished, start up is complete and

the unit is ready for bar hole testing.

Bar Hole Testing

In Bar Hole Mode, the you can initiate sampling for a fixed time period to monitor for
methane and oxygen in a bar hole. The factory set time is 30 seconds. To change the bar
hole sampling time, see “Updating the Bar Hole Sampling Time” on page 126. At the end
of the sample period, the pump will shut off and the peak methane and minimum oxygen
levels monitored during the sample period will be displayed. Bar Hole Mode also allows
you to initiate an air purge cycle to purge gas from the GX-2012 after a sample is taken.

In a low-light environment, press and release the (SHIFT) button to turn on the display
backlight. Although the backlight will turn on when any button is pressed, other buttons
may initiate an undesired operation sequence. See “Updating the LCD Back Light Time
Setting” on page 123 to program backlight duration. If BEEP. SET is turned on in the
Maintenance Mode menu, the GX-2012 beeps once every 5 minutes to confirm that it’s
operating.

While in Bar Hole Mode, you may select or change the current station ID by pressing the
(SHIFT) button and DISPLAY (ADJ) button and releasing when you hear a beep.

Performing a Ba r Hole Test

1. Start up the GX-2012 as described in “Start Up, Bar Hole Mode” on page 69.

2. If you wish to change the station ID, press the (SHIFT) and DISPLAY (ADJ)
buttons and release when you hear a beep. The current station ID will be displayed
and it will be flashing. If you wish to exit the Station ID Select Screen without
making any changes, press and release the RESET SILENCE button.

Use the AIR and (SHIFT) buttons to scroll to the desired station ID and press and
release POWER ENTER. The unit will return to the Bar Hole Measuring Screen.

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GX-2012 Operator’s Manual Bar Hole Testing • 75

3. Take the GX-2012 to the bar hole that will be tested.

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4. Insert the probe into the bar hole and press and release the POWER ENTER button.

25

20.9
30

vol%

%

BAR HOLE MODE

sec

CH4

O2

MEASURE

25

19.0

%LEL

%

BAR HOLE MODE

CH4

O2

PEAK

PEAK

0

20.9
30

vol%

%

BAR HOLE MODE

sec

CH4

O2

PURGE

The pump will turn on and the sample period will begin with the sample period
counting down in seconds in the lower right corner of the display. The CH4 channel

will be displayed in %VOL. The methane channel’s reading will also be displayed in
graph format on the left side of the screen. If you wish to cancel the measurement,
press and release the RESET SILENCE button.

5. After 15 seconds of sampling, if the combustible gas reading is less than 5 %VOL, the
combustible gas channel will automatically begin displaying in %LEL.

6. At the end of the sample period, the pump will shut off and the buzzer will sound,
then the peak methane reading and the minimum oxygen reading for the sample
period will be displayed. The peak metha ne reading will al so be visu ally dis played on
the graph along the left side of the screen.

7. If a high concentration of methane is encountered, a fresh air purge can be performed
to purge the hose, probe and GX-2012 of gas before the next bar hole test. To perform
a purge, do the following:

• Remove the probe from the barhole so the instrument will draw fresh air.

• Press and release the DISPLAY (ADJ) button. The display will now indicate

PURGE along the bottom of the screen and the purge time will begin counting
down from 30 seconds in the lower right corner of the display. If you wish to
cancel the purge, press and release the RESET SILENCE button.

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• When the purge is complete, the screen will return to the initial Bar Hole Mode

0

20.9

%LEL

%

BAR HOLE MODE

CH4

O2

001

screen.

8. If other bar holes will be tested, proceed to the next bar hole and repeat steps 4 - 7.

9. To cancel a bar hole measurement or fresh air purge that is in progress, press and
release the RESET SILENCE button.

10. To exit Bar Hole Mode and return to the Mode Select Screen at any time, press and
hold the (SHIFT) button for 5 seconds.

Turning Off the GX-2012, Bar Hole Mode

1. Press and hold the POWER ENTER button.

2. The unit will initiate a bar hole measurement. Keep holding the POWER ENTER
button. The buzzer will pulse for about three seconds and TURN OFF will appear at
the bottom of the screen.

3. Release the button when TURN OFF disappears.

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GX-2012 Operator’s Manual Bar Hole Testing • 77

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Chapter 5: Using the GX-2012 in Leak Check Mode

Overview

This chapter explains how to operate the GX-2012 in Leak Check Mode. Leak Check
Mode is used to pinpoint small leaks of combustible gas from valves, flanges,
connections, and other potential leak points. When the GX-2012 is in Leak Check Mode,
only the combustible channel is displayed.

If a GX-2012 is intended for leak check testing, it is shipped with Leak Check Mode
enabled so that the operator must choose which operational mode to use when the unit is
turned on (see “Turning On the GX-2012 in Normal Mode With All Modes Active” on
page 28).

Start Up, Leak Check Mode

This section explains how to start up the GX-2012 in Leak Check Mode and get it ready
for operation.

NOTE: The battery drain is higher in Leak Check Mode than in Normal Mode

or Bar Hole Mode. Extended operation in this mode will result in
shorter battery life than specified in “Specifications” on page 9.

Turning On the GX-2012, Leak Check Mode

WARNING: If an oxygen or H2S sensor is installed, these sensors will not be

active while the GX-2012 is in Leak Check Mode.

The following description of the GX-2012 start up sequence assumes that the following
menu items in Maintenance Mode are turned on: LNCH BRK, ID DISP, CL RMNDR,
and BP RMNDR. If either of these items is turned off, then the corresponding screen will
not appear.

NOTE: In order for LEAK CHECK MODE to appear as a selection in the Mode

Select Screen in Step 3 below, the L./B. MODE item in Maintenance Mode
must be set to LC or LC bH. The factory setting is OFF.

1. Connect the tapered rubber nozzle to the inlet fitting.

2. If a sample hose is used, connect the sample hose to the GX-2012’s quick connect inlet

fitting.

NOTE: If a probe is used when using the GX-2012 in Leak Check Mode, use the

standard probe, not the bar hole probe.

78 • O v e r v i e w GX-2012 Operator’s Manual

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3. Press and briefly hold down the POWER ENTER button. The Normal Mode Select

0

20.9
0

0.0

vol%
%LEL

%

ppm

ppm

CH4

O2

NORMAL ?

CO
H2S

CO DISP OFF CO DISP On

0

5000

ppm

ppm

LEAK CK MODE

CH4

L.C. MODE?

0
0

5000

ppm

ppm

ppm

LEAK CK MODE

CH4

L.C. MODE?

CO

Screen displays.

4. Use the AIR or (SHIFT) button to scroll to the Leak Check Mode Select Screen.

NOTE: If the CO DISP parameter in Maintenance Mode is set to On, the CO channel

will appear in Leak Check Mode. If the CO DISP parameter is set to OFF
(factory setting), the CO channel will not appear in Leak Check Mode. All
screens in this section do not show the CO channel. If CO DISP is turned on for
your instrument, your screens may appear different.

5. With the Leak Check Mode Select Screen displayed, press and release the POWER

ENTER button to begin the Leak Check Mode startup sequence.

NOTE: If no button is pressed for 20 seconds, the unit will proceed into whichever

mode is displayed.

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GX-2012 Operator’s Manual Start Up, Leak Check Mode • 79

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6. If CL RMNDR is turned on (factory setting), the screen that appears next depends on

CAL

C--LIMIT

FAIL

C--LIMIT

2011
9
30
69d

NEXT CAL

how CL EXPRD is set in the Maintenance Mode Menu ((pg. 119)).

• If the unit is due for calibration and CL EXPRD is set to CONFIRM (factory

setting), then the following screen displays.

The alarm LED’s and buzzer will pulse several times. After this, press and
release the RESET SILENCE button to continue.

• If the unit is due for calibration and CL EXPRD is set to NOT USE, then the

following screen displays.

The GX-2012 cannot be used until a calibration has been performed either by
selecting AUTO CAL, or ONE CAL in the Maintenance Mode menu. See
“Calibrating Using Auto Calibration” on page 97 or “Calibrating Using Single
Calibration” on page 100 for calibration instructions.

• If calibration is not due or CL EXPRD is set to NO EFFECT, then the f ollowing

screen appears for a few seconds indicating when the next calibration is due.

80 • S t a r t U p , L e a k C h ec k M o d e GX-2012 Operator’s Manual

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7. If BP RMNDR is turned on (factory setting is OFF), the screen that appears next

tESt

B--LIMIT

FAIL

B--LIMIT

2011
9
30
10d

NEXTBUMP

depends on how BP EXPRD is set in the Maintenance Mode Menu ((pg. 121)).

• If the unit is due for a bump test and BP EXPRD is set to CONFIRM (factory

setting), then the following screen displays.

The alarm LED’s and buzzer will pulse several times. After this, press the
RESET SILENCE button until you hear a beep to continue.

• If the unit is due for a bump test and BP EXPRD is set to NOT USE, then the

following screen displays.

The GX-2012 cannot be used until a bump test has been performed by selecting
BUMP in the Maintenance Mode menu. See “Performing a Bump Test” on
page 102 for bump testing instructions.

• If a bump test is not due or BP EXPRD is set to NO EFFECT, then the following

screen appears for a few seconds indicating when the next bump test is due.

NOTE: If both CL RMNDR and BP RMNDR are turned off, a WARM UP screen will

display before the warm up sequence continues.

GX-2012 Operator’s Manual Start Up, Leak Check Mode • 81

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8. If ID DISP is turned on, the User ID Screen displays for a few seconds and then the

U Id

- - - - - - - -

S Id

- - - - - - - -

2011
8
31
22:39

DATE

Station ID Screen displays for a few seconds.

9. The Date/Time Screen appears for a few seconds.

This screen displays the current year, month, date, and time.

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10. The Battery Level and Alarm Pattern Screen appears next.

bAtt

3.7

AL-H V

bAtt

3.7

AL-H D: V

FAIL

%LEL

CH4

SENSOR

AL -- H indicates latching (hold) alarms and AL -- A indicates self-resetting
(automatic) alarms. The number shown indicates the voltage of the batteries. If the
unit is powered by alkaline (dry cell) batteries, a “D” will appear before the “V” in the
lower right corner.

11. The display then indicates the full scale values for all channels.

12. If the GX-2012 experiences a sensor failure during start up, a screen indicating which

sensor failed displays. In the example below, the catalytic LEL sensor has failed.

If the catalytic LEL sensor fails, it is not possible to enter Leak Check Mode. Press and
release the RESET SILENCE button twice to acknowledge the failure and return to
the Mode Select Screen. Replace the failed sensor as soon as possible.

If the oxygen, CO, or H
SILENCE button to acknowledge the failure and continue to Leak Check Mode.

If a vol% sensor is installed and fails, no indication will be given and the unit will
enter Leak Check Mode.

S sensor is installed and fails, press and release the RESET

2

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GX-2012 Operator’s Manual Start Up, Leak Check Mode • 83

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13. The GX-2012 is now operating in Leak Check Mode.

0

5000

ppm

ppm

LEAK CK MODE

CH4

F.S.

AIr
CAL

HOLD AIR

The combustible gas reading is displayed along with the battery charge level.

Performing a Fresh Air Adjustment , Leak Check Mode

Before using the GX-2012 for leak checking, it is recommended to set the fresh air reading
by performing a fresh air adjustment. This will set the combustible gas channel to zero.
RKI Instruments recommends allowing the GX-2012 to run for as long as possible after
turning on the instrument before performing a fresh air adjustment.

1. Find a fresh-air environment. This is an environment free of toxic or combustible

gases and of normal oxygen content (20.9%).

2. Turn on the unit as described above in “Turning On the GX-2012, Leak Check Mode”

on page 78.

3. Press and hold the AIR button. The display will prompt you to hold the AIR

button.

4. Continue to hold the AIR button until the display prompts you to release the AIR

button. The GX-2012 will set the fresh air reading for the combustible channel. Once
the fresh air adjustment has finished, start up is complete and the unit is ready for leak
testing.

5. If you would like to calibrate the GX-2012 while in Leak Check Mode, follow the

same instructions described in “Calibration Mode” on page 56.

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Leak Testing

0

500

ppm

ppm

LEAK CK MODE

CH4

F.S.

In Leak Check Mode, the GX-2012 only displays combustible gas readings. The
increment of the reading is always 100 ppm but the display range can be adjusted by using
the DISPLAY (ADJ) button. The display range choices are 500 ppm, 1000 ppm, 2000
ppm, and 5000 ppm. The readings are displayed in bo th numerical and bar graph form. As
the gas concentration increases from 0 ppm, the alarm LEDs begin to blink in unison with
the buzzer’s pulsing. The blinking/pulsing rate increases as the gas reading increases. If
desired the buzzer can be turned off in Leak Check Mode.

In a low-light environment, press and release any of the buttons to turn on the display
backlight. If BEEP. SET is turned on in Maintenance Mode, the GX-2012 beeps once
every 5 minutes to confirm that it’s operating.

Setting the Display Range Value

The GX-2012 Leak Check Mode has 4 display range ppm values to choose from: 500
ppm, 1000 ppm, 2000 ppm, and 5000 ppm.

NOTE: The GX-2012 is always detecting combustible gas up to 5000 ppm. The display

range value is only adjusting what part of the detection range is displayed on the
LCD.

To change the display range value:

1. While in Leak Check Mode, press and release the DISPLAY (ADJ) button. The

display range value displayed along the bottom of the screen will change.

Continue to press and release the DISPLAY (ADJ) button until the desired display
range value is displayed.

2. The unit is now operating with the selected display range.

Locating a Leak

1. Start up the GX-2012 as described above in “Turning On the GX-2012, Leak Check

Mode” on page 78.

2. Move the probe tip or tapered nozzle tip back and forth along the area where a leak is

suspected.

3. Observe the display reading. If the gas level increases, the numerical reading will

increase, the bar graph level will increase, and the beeping and buzzer pulsing
frequency will increase.

4. Your gas reading may exceed your display range or 100% LEL. For a description of

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GX-2012 Operator’s Manual Leak Testing • 8 5

both scenarios, see the following section.

5. Use the increasing and decreasing of the reading to locate the leak point.

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6. To exit Leak Check Mode and return to the Leak Check Mode Select Screen at any

32

5000

%LEL

ppm

LEAK CK MODE

CH4

OVER

5000

%LEL

ppm

LEAK CK MODE

CH4

OVER

time, press and hold the (SHIFT) button for 5 seconds.

Overscale Conditions

There are three overscale conditions that the GX-2012 may experience while operating in
Leak Check Mode.

• Exceeding display range

If you are using a display range of 500, 1000, or 2000 ppm and the gas level goes
above the display range, the full scale value of the display range will be displayed but
it will not be an overscale condition unless the gas level is above 5000 ppm.

• Exceeding 5000 ppm

If the combustible gas level exceeds 5000 ppm, the GX-2012 will display an overscale
condition but will continue displaying the gas reading in %LEL.

• Exceeding 100% LEL

If the combustible gas level exceeds 100% LEL, the GX-2012 will display an
overscale alarm.

NOTE: If a vol% sensor is installed, “OVER” will still appear at the bottom of the

screen but the instrument will display the gas reading in %volume.

The GX-2012 will continue to be in overscale alarm until the gas reading decreases.
The instrument will then show readings in the LEL range until the readings decrease
back to the ppm range.

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Turning the Alarm On and Off in Leak Check Mode

400
PH
500
500

ppm

ppm

ppm

LEAK CK MODE

CH4

F.S.

PEAK

The alarm buzzer can be turned off and on when the GX-2012 is in Leak Check Mode.
This setting only applies to Leak Check Mode and does not affect buzzer operation in
Normal or Bar Hole Mode. When the buzzer is set to Off, NO ALARM appears in the
upper left hand corner of the display. If the buzzer is turned off, then it will remain off in
Leak Check Mode even if you enter Normal Mode or Bar Hole Mode and return to Leak
Check Mode or turn the unit off and on unless the buzzer is manually turned on.

To turn the buzzer off or on while in Leak Check Mode:

1. Press and hold the DISPLAY(ADJ) button for 5 seconds.

NOTE: Pressing and holding the DISPLAY (ADJ) button will change the full scale

setting for Leak Check Mode. Once you have made your buzzer selection, use
the DISPLAY (ADJ) button to display the desired full scale.

2. Release the button when NO ALARM in the upper left corner appears or disappears.

Peak Hold Mode

Peak Hold Mode allows the user to view the peak methane reading for the operating
session while viewing the current methane reading.

To enter Peak Hold Mode:

1. Turn the GX-2012 on as described in “Turning On the GX-2012, Leak Check Mode”

on page 78. Select the desired display range. In the example below, 500 ppm has been
selected.

2. Press and hold the RESET SILENCE button until the Peak Hold Mode screen

displays.

The current methane reading is displayed on the first line. The “PH” shown on the
second line indicates that the GX-2012 is in Peak Hold Mode. The peak methane
reading is displayed on the third line. The full scale value is displayed on the fourth
line.

3. The peak reading displayed while in Leak Check Mode will appear in the Peak Hold

Mode screen.

4. If the highest reading recorded is higher than the full scale value, the full scale value

will be displayed. If the full scale value is changed to something higher, the real value
for the peak will be displayed.

5. To reset the peak, press and hold the RESET SILENCE button until you hear a beep,

then release it.

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GX-2012 Operator’s Manual Leak Testing • 8 7

SILENCE button until you hear the GX-2012’s second beep and the Leak Check
Mode Screen displays.

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6. To exit Peak Hold Mode and return to Leak Check Mode, press and hold the RESET

Snap Log Mode, Leak Check Mode Operation

S Id

001

SEL

0

500

ppm

ppm

LEAK CK MODE

CH4

BASE

The snap logging function in Snap Log Mode allows the user to record data at a specific
time and have it saved to the data logger. The data is assigned a snap log ID and is saved
with the station ID that was selected when the data was taken.

To enter Snap Log Mode and record snap log data:

1. Turn the GX-2012 on as described in “Turning On the GX-2012, Leak Check Mode”

on page 78. Select the desired display range. In the example below, 500 ppm has been
selected. Press and hold the (SHIFT) button, then press and hold the AIR button
and hold both until you hear a beep. The Station ID Select Screen will display and the
current station ID will be flashing.

NOTE: If the gas levels reach a warning or alarm condition while in this screen, the

GX-2012 will go into alarm.

2. Use the (SHIFT) and AIR buttons to scroll to the desired station ID, then press

and release the POWER ENTER button to continue to the Base Reading Screen. To
return to the Station ID Select Screen without taking a base reading, press and release
the RESET SILENCE button.

3. In order to get a base, or background, reading, take the instrument a few feet away

from where you intend to test. To save the base reading, press and release the POWER
ENTER button.

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NOTE: If the gas concentration exceeds the display range value without exceeding

0

500

ppm

ppm

LEAK CK MODE

CH4

PEAK

PEAK

5000 ppm, the full scale display range value will be displayed but the actual gas
reading at that time will be recorded when you press and release POWER
ENTER. For example, if the display range is 500 ppm but the gas level is 2300
ppm, the display will read 500 ppm but the instrument will save a reading of
2300 ppm.

If the gas concentration exceeds 5000 ppm in the Base Reading Screen, the
instrument will go into an overscale alarm. The full scale display range value
will be displayed but OVER will be recorded when you press POWER ENTER.
The full scale display range value will continue to be displayed in the Peak
Reading Screen and OVER will again be recorded when you press POWER
ENTER.

4. The unit will display SAVED along the bottom of the screen before continuing to the

Peak Reading Screen.

5. Take the instrument to the monitoring area. The instrument will retain and display the

highest gas concentration encountered. To save the peak reading, press and release the
POWER ENTER button. The reading on the screen (the highest concentration
encountered) will be saved.

NOTE: If the gas concentration exceeds the display range without exceeding 5000 ppm,

the full scale display range value will be displayed but the actual gas rea ding at
that time will be recorded when you press and release POWER ENTER. For
example, if the display range is 500 ppm but the gas level is 2300 ppm, the
display will read 500 ppm but the instrument will save a reading of 2300 ppm.

If the gas concentration exceeds 5000 ppm in the Peak Reading Screen, the
instrument will go into an overscale alarm. The full scale display range value
will be displayed and OVER will be recorded when you press POWER
ENTER.

The unit will display SAVED along the bottom of the screen before returning to the
Station ID Select Screen.

To return to the Station ID Select Screen without taking a peak reading, press and
release the RESET SILENCE button.

6. Repeat steps 2 through 5 to take additional snap log data.

7. T o exit Snap Log Mode at any time without taking a snap log or when you are finished

recording snap logs, press and release the DISPLAY (ADJ) button. The unit will
immediately return to the Normal Operation Screen.

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GX-2012 Operator’s Manual Leak Testing • 8 9

8. The data recorded in Snap Log Mode can be viewed in Display Mode. See “Snap

Logging Screen” on page 53 for more information.

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Viewing Snap Log Data in Leak Check Mode Operation

NO DATA

2012
2
15
14:17

LEAK CK MODE

M009

2011
8
31
22:39

M023

Normal Operation Leak Check Mode Operation

Snap Log Snap Log

Snap log data can be viewed while in Leak Check Mode. If snap log data was taken while
in Normal Operation, that data will also appear.

1. Turn the GX-2012 on as described in “Turning On the GX-2012, Leak Check Mode”

on page 78.

2. Press and hold the RESET SILENCE button and then press and hold the DISPLAY

(ADJ) button and release both.

3. If no snap logs have been performed, the following screen will appear.

Press and release the DISPLAY (ADJ) button to return to Leak Check Mode.

4. If snap logs have been performed in either Normal Operation or Leak Check Mode

Operation, one of the following screens will appear. LEAK CK MODE will appear in
the upper left corner of Leak Check Mode Operation data to indicate that the snap log
was taken during Leak Check Mode Operation.

This screen indicates the year, month, day, and time that the most recent snap log was
taken. The number along the bottom of the screen indicates the snap log ID number.
The first snap log that is taken is given an ID of M001. The next snap log ID is M002.
The ID number increases sequentially with each set of snap log data. Use the AIR

and (SHIFT)
and day they were taken. Snap log data that was taken in Leak Check Mode operation
will have two snap log ID numbers. One number is for the base reading and the other
is for the peak reading.

90 • L e a k T e s t i n g GX-2012 Operator’s Manual

buttons to scroll through different snap log IDs and view what time

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5. To view the data in a snap log ID, press and release the POWER ENTER button. You

2011
8
31
22:39

M011

2012
2
15
14:17

LEAK CK MODE

M009

2012
2
15
14:18

LEAK CK MODE

M010

POWER

50

23.5
50

%LEL

%

ppm

CH4

O2

BLDNG 1

CO

4500

5000

ppm

ppm

LEAK CK MODE

CH4

VALVE 3

PEAK

0

5000

ppm

ppm

LEAK CK MODE

CH4

VALVE 3

2011
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22:39

M007

35

22.0
45

%LEL

%

ppm

CH4

O2

RIG

CO

ENTER

POWER

ENTER

POWER

ENTER

POWER

ENTER

Operation

Data

Normal

Operation

Data

Normal

Leak Check

Mode Operation

Leak Check

Mode Operation

Peak Data

Base Data

AIR

(SHIFT)

AIR

(SHIFT)

AIR

(SHIFT)

can also go back and forth between the ID and data screens by pressing and releasing
the POWER ENTER button.

GX-2012 Operator’s Manual Leak Testing • 9 1

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The gas readings that were taken during the snap log are displayed and the Station ID
that was in use during the snap log is displayed along the bottom of the screen. Snap
log data that was taken in Leak Check Mode operation will have 2 sequential screens
that are part of one data set. One screen is for the base reading and the other screen is
for the peak reading. The peak reading value will have PEAK displayed below the
peak bar. If a base data point appears without a peak data point after it, it is because a

peak data point was not taken. You can use the AIR and (SHIFT) buttons to scroll
through the different snap logs. The gas readings and station ID will change but the
snap log ID is not visible from this screen.

6. To exit snap log data viewing and return to Leak Check Mode Operation, press and

release the DISPLAY (ADJ) button.

Turning Off the GX-2012, Leak Check Mode

1. Press and hold the POWER ENTER button.

2. The buzzer will pulse for about three seconds and TURN OFF will appear at the

bottom of the screen.

3. Release the button when TURN OFF disappears.

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Chapter 6: Maintenance Mode

Overview

This chapter describes the GX-2012 in Maintenance Mode. In Maintenance Mode, you
can:

• update the date and time (pg. 95)

• perform a fresh air adjust (pg. 96)

• perform an auto calibration (pg. 97)

• perform a single calibration (pg. 100)

• perform a bump test (pg. 102)

• turn the lunch break setting on or off (pg. 107)

• update the alarm latching setting (pg. 108)

• turn alarm silencing on or off (pg. 109)

• update the interval trend time setting (pg. 110)

• update warning, alarm, STEL, and TWA settings (pg. 110)

• turn the clear data logger screen on or off (pg. 114)

• turn the bump test function on or off (pg. 115)

• turn the pump off screen on or off (pg. 115)

• update bump test parameters (pg. 116)

• update the confirmation beep setting (pg. 117)

• update the data logger overwrite setting (pg. 118)

• update the calibration interval setting (pg. 118)

• turn the calibration reminder function on or off (pg. 119)

• update the calibration expired action setting (pg. 119)

• update the calibration check setting (pg. 120)

• update the bump test interval setting (pg. 120)

• turn the bump test reminder function on or off (pg. 121)

• update the bump test expired action setting (pg. 121)

• update the bump test check setting (pg. 122)

• turn the ID display function on or off (pg. 123)

• update the backlight settings (pg. 123)

• turn the autozero function on or off (pg. 124)

• turn the demand zero function on or off (pg. 124)

• update the Leak Check/Bar Hole Mode setting (pg. 125)

• update the bar hole sampling time (pg. 126)

• turn Portuguese on or off (pg. 126)

GX-2012 Operator’s Manual Overview • 93

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• update the Leak Check Mode CO channel display setting (pg. 127)

0000

MAINTENANCE

PASSWORD

• view the instrument’s firmware version and checksum information (pg. 128)

• turn the password function on or off and set the password (pg. 128)

The GX-2012 is factory-set to suit most applications. Update settings in Maintenance
Mode only if required for your specific application.

Tips for Using Maintenance Mode

•Use (SHIFT) to scroll down through the main menu and submenus, and to lower

values or change the setting in a specific option.

•Use AIR to scroll up through the main menu and submenus, and to raise values or

change the setting in a specific option.

• Use the POWER ENTER button to enter a selected menu item, and to enter and save

settings that have been updated.

• An adjustable parameter that is flashing can be adjusted with the AIR and

(SHIFT) buttons.

• Press the DISPLAY (ADJ) button while entering or updating parameters to exit the

screen without saving any changes.

Using Maintenance Mod e

W ARNING: The GX-2012 is not in operation as a gas detector while in Maintenance

Mode. Although it will respond to gas in parts of AUTO CAL and ONE
CAL, there are no alarm indications.

1. Take the GX-2012 to a non-hazardous location, and turn it off if it is on.

2. Press and hold the AIR and (SHIFT) buttons, then press and hold the POWER
ENTER button. When you hear a beep, release the buttons.

The unit will prompt you for a password.

3. Enter the password by using the AIR and (SHIFT) buttons to select each
password number and then pressing and releasing POWER ENTER to enter it and
move on to the next one. To go back a number, press and release the RESET
SILENCE button.

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94 • T i p s f o r U s i n g M a i nt e n a n c e M o d e GX-2012 Operator’s Manual

NOTE: A password is always needed to enter Maintenance Mode even if the

PASSWORD menu item in Maintenance Mode has been turned off (factory

setting). The factory set password is 2102. You may change this password by
entering the PASSWORD menu item in Maintenance Mode.

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4. If you enter an incorrect password, an error screen will appear.

Err

PASSWORD

MAINTENANCE

DATE

MAINTENANCE

DATE

2011
4
23
22:37

MAINTENANCE

DATE

You must turn the unit off and reenter Maintenance Mode using the correct password.

5. Once you enter Maintenance Mode, MAINTENANCE will appear along the top of
the screen. The Date Screen displays.

6. Use the AIR or (SHIFT) button to move through the menu item screens.

Updating the Date and Time Settings

1. Use the AIR or (SHIFT) buttons to display the DATE menu item.

Press and release the POWER ENTER button. The date and time will be displayed
with the year flashing.

2. Use the AIR or (SHIFT) button to display the desired year.

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3. Press and release the POWER ENTER button to save the setting. The month setting

MAINTENANCE

AIR CAL

0

20.9
0

0.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

PUSH AIR

CO
H2S

AIr
CAL

MAINTENANCE

HOLD AIR

flashes.

4. Repeat steps 2 and 3 to enter the month, day, hours, and minutes settings. The Date
menu item displays after you enter the minutes setting.

Performing a Fresh Air Adjustment

1. Confirm you are in a fresh air environment that is free of toxic and combustible gases
and of normal oxygen concentration, 20.9%.

2. Use the AIR or (SHIFT) buttons to navigate to the AIR CAL menu option.

3. Press and release the POWER ENTER button to enter AIR CAL. The current gas
readings are displayed.

4. Hold down the AIR button. The unit will prompt you to continue holding the
AIR button.

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5. When the unit tells you to release the AIR button, release it. The unit will count

AdJ
8

MAINTENANCE

sec

RELEASE

down from 8 as it performs the fresh air adjust.

Once it has finished, it will return to the AIR CAL menu screen.

Calibrating Using Auto Calibration

If CL EXPRD is set to NOT USE and calibration becomes due, then the unit must be
calibrated using this menu item and/or the next menu item, ONE CAL, because it will not
be possible to enter normal operation. See “Calibration/Bump Test Supplies and
Equipment” on page 56 for the items you will need to perform a calibration. These
instructions assume you are using a 4-gas cylinder and a %volume methane cylinder.

NOTE: If the combustible gas channel(s) are calibrated to a gas other than

methane, use an appropriate multigas cylinder or use single calibration
to calibrate the combustible channel(s).

1. Perform a fresh air adjust. See previous section for instructions.

2. Install the demand flow regulator onto the calibration cylinder.

3. Connect the sample tubing to the demand flow regulator.

4. Install the hose and probe to the GX-2012.

5. You may only calibrate either the standard 4 sensors or the % volume combustible gas
sensor at a time. Once you are finished, you are returned to the initial AUTO CAL
screen and must begin the auto calibration process again.

6. Use the AIR or (SHIFT) buttons to display the AUTO CAL menu item. Press
and release the POWER ENTER button to display the calibration values screen. If
you want to exit back to the main menu without completing a calibration, press and
release the DISPLAY (ADJ) button.

GX-2012 Operator’s Manual Using Maintenance Mode • 97

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7. Use the AIR or (SHIFT) button to alternate between the 4-gas and the %volume

50

12.0
50

25.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

AUTO CAL

CO
H2S

100

vol%

MAINTENANCE

CH4

AUTO CAL

- - -

%LEL

MAINTENANCE

CH4

AUTO CAL

combustible gas calibration values screen.

8. The gas concentrations displayed in the calibration values screens must match the gas
concentrations listed on the calibration cylinders. If all concentrations match, go to
step 16. If one or more concentrations do not match, continue with step 9.

9. To adjust the values on the screens, hold down the (SHIFT) button, then press the
DISPLAY(ADJ) button and release both. The %LEL sensor is shown.

10. Use the AIR and (SHIFT) buttons to scroll through the sensors and select the
sensor whose calibration gas value you want to adjust.

11. Press and release the POWER ENTER button. The sensor’s calibration gas value will
flash.

12. If necessary, use the AIR and (SHIFT) buttons to set the correct calibration gas
value.

13. Press and release the POWER ENTER button to save the change.

14. Repeat steps 10 through 13 to set the correct values for any additional sensors.

15. After the last calibration gas value is set, use the AIR button to scroll to ESCAPE
and press POWER ENTER to return to the calibration gas values screen.

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98 • U s i n g M a i n t e n a n ce M o d e GX-2012 Operator’s Manual

NOTE: The RKI Four Gas Cylinder typically contains 12% O2 by volume. Be sure to

set the “OXY” reading to agree with the concentration listed on the cylinder’s
label, not zero.

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16. Use the AIR and (SHIFT) buttons to select which sensor(s) you want to

0

20.9
0

0.0

%LEL

%

ppm

ppm

MAINTENANCE

CH4

O2

AUTO CAL

CO
H2S

%

ppm

MAINTENANCE

O2

FAIL

H2S

calibrate, the standard 4 sensors or the %volume combustible gas sensor.
The following instructions illustrate calibrating the standard 4 sensor first, then the

%volume combustible gas sensor.

17. With the calibration values screen displayed, press the POWER ENTER button.
AUTO CAL begins to flash and the current gas readings are displayed.

18. Connect the tubing from the demand flow regulator to the rigid tube on the probe.
Allow the gas to flow for one minute.

19. Press and release the POWER ENTER button to set the calibration to the
programmed values.

If all channels passed calibration, P AS S displays along the bottom of the screen, then
the calibration menu displays.

If any of the sensors cannot calibrate to the proper value, FAIL displays along the
bottom of the screen and the GX-2012 lists the sensor(s) that failed to calibrate. In the
example below, the OXY and H2S channels failed calibration. The other sensors

calibrated normally.

The buzzer and alarm lights activate. Press and release the RESET SILENCE button
after the buzzer and lights stop to reset the alarm and return to the calibration menu.
Attempt to calibrate again. If the failure continues, investigate the cause. See
“Troubleshooting” on page 131.

20. Disconnect the tubing from the probe.

21. Unscrew the demand flow regulator from the calibration cylinder.

22. If you have a 5 sensor unit and wish to calibrate the %volume combustible gas sensor ,
go back to step 1 and repeat the process, selecting the %volume calibration gas value
screen in step 16 and using a %volume methane calibration cylinder.

If you are finished calibrating, use the (SHIFT) button to navigate to the
NORMAL menu item, then press and release the POWER ENTER button to return to
Measuring Mode.

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Calibrating Using Single Calibration

MAINTENANCE

ONE CAL

If CL EXPRD is set to NOT USE and calibration becomes due, then the unit must be
calibrated using this menu item and/or the previous menu item, AUTO CAL because it
will not be possible to enter normal operation. See “Calibration/Bump Test Supplies and
Equipment” on page 56 for the items you will need to perform a calibration.

The procedure below describes a span adjustment of one channel using a calibration kit
that includes a 4-gas calibration cylinder, a 0.5 LPM (liters per minute) regulator , and non­absorbent sample tubing. The standard 4-gas cylinder consists of 50% LEL methane, 12%
oxygen, 50 ppm CO, 25 ppm H2S, and a balance of nitrogen. In the example below, the

CH4 channel’s span is adjusted. See “Chapter 8: Parts List” on page 145 for available
calibration kits and calibration kit spare parts.

Calibration cylinders that contain only one target gas may also be used for single
calibration. For channels other than oxygen, RKI Instruments, Inc. recommends that you
use a cylinder that contains a concentration of 10-50% of the full scale value of the target
gas. For example, if you are calibrating the combustible gas channel, your calibration
cylinder should have a combustible gas concentration between 10% LEL and 50% LEL.
For the oxygen channel, RKI Instruments, Inc. recommends using 100% nitrogen to
perform the adjustment but any concentration between 0% oxygen (100% nitrogen) and
17% oxygen can be used to make the adjustment.

NOTE: If your combustible gas channel is calibrated to a gas other than methane, use

an appropriate gas cylinder to perform the calibration.

CAUTION: The single calibration method does not have a “FAIL” notification. If a

sensor cannot be set to agree with the calibration source, see
“Troubleshooting” on page 131.

1. Perform a fresh air adjust. See “Performing a Fresh Air Adjustment” on page 96 for
instructions.

2. Install the demand flow regulator onto the calibration cylinder.

3. Connect the sample tubing to the demand flow regulator.

4. Install the hose and probe to the GX-2012.

5. Use the AIR or (SHIFT) buttons to scroll to the ONE CAL menu option.

10 0 • U s i n g M a i n t e n a n c e M od e GX-2012 Operator’s Manual

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