RKI Instruments CO-04 User manual

RKI Instruments, Inc.
www.rkiinstruments.com
CO-04
Operator’s Manual
Part Number: 71-0600
Revision: P1
Released: 8/9/22

2• CO-04 Operator’s Manual
WARNING
Read and understand this instruction manual before operating
instrument. Improper use of the gas monitor could result in bodily
harm or death.
Maintenance of the gas monitor is essential for proper operation and
correct readings.
Bump test the instrument before each day’s use with a known
concentration of the target gas. A bump test can be done in User
Mode’s BUMP item or by applying gas in Measuring Mode. The
instrument does not need to be calibrated unless it does not pass the
User Mode bump test or does not respond appropriately, as defined by
the user, in Measuring Mode. For more information about bump test
and calibration requirements, see IEC 60079-29-2.

CO-04 Operator’s Manual • 3
Table of Contents
Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
About the CO-04. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
About this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Chapter 2: Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Instrument Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
LCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Control Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Alarm LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Buzzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Vibrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Infrared Communications Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Standard Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Alligator Clip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Watch Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Calibration Cup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
IrDA/USB Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Chapter 3: Measuring Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Turning On the CO-04 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Performing a Demand Zero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Turning Off the CO-04 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4• CO-04 Operator’s Manual
Measuring Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Monitoring an Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Responding to Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Data Logging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Chapter 4: Display Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Tips for Using Display Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Peak Screen (PEAK). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
STEL Screen (STEL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
TWA Screen (TWA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
User ID Screen (USER ID). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Station ID Screen (STN ID) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Last Successful Calibration Date (CAL.DATA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Last Successful Bump Test Screen (BP.DATA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Date/Time Screen (DATE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Temperature Screen (TEMP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Alarm Points Screen (ALARM--P) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Adjusting the Buzzer Volume (BUZZ.VOL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Chapter 5: User Mode and Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Entering User Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Tips for Using User Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Performing a Bump Test (BUMP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Performing a Calibration (GAS CAL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Setting Calibration Parameters (CAL SET) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Setting Bump Test Parameters (BUMP.SET) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Alarm Settings (ALARM--P) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Updating the Lunch Break Setting (LUNCH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Setting the Confirmation Beep and Non-Compliance Indicator (BEEP) . . . . . . . . . . . . . 63
Updating the Backlight Time (BL TIME). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Turning the Key Tone On/Off (KEY.TONE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

CO-04 Operator’s Manual • 5
Display Mode Items (DISP.SET) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Zero Suppression (ZERO.SUP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Zero Follower (ZERO.FLW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Turning Easy Calibration On/Off (E-CAL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Setting the Date/Time (DATE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Turning the Password On/Off (PASS-W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Viewing the ROM/SUM (ROM/SUM). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Entering Measuring Mode (START) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Chapter 6: Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Replacing the Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Replacing the Charcoal Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Replacing the Hydrophobic Filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Replacing the Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Chapter 7: General Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Appendix A: Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Entering Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Tips for Using Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Performing a Calibration (GAS CAL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Performing a Gas Test (GAS.TEST). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Sensor/Battery Replacement Date (SEN.DATE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Performing a Bump Test (BUMP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Setting Alarms to Latching or Self-Resetting (LATCH) . . . . . . . . . . . . . . . . . . . . . . . . . 86
Turning the Demand Zero Function On/Off (D.ZERO) . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Turning the Auto Zero Function On/Off (A.ZERO). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Turning the ID Display Function On/Off (ID DISP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Turning the Zero Suppression On/Off (ZERO.SUP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Turning the Zero Follower On/Off (ZERO.FLW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
User Mode Zero Suppression (ZSUP.DSP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6• CO-04 Operator’s Manual
User Mode Zero Follower (ZFLW.DSP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Cylinder Setting (CYL.DISP). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Setting the Date/Time (DATE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Turning the Password On/Off (PASS-W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Viewing the ROM/SUM (ROM/SUM). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Performing a Default (M.DEF). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Entering Measuring Mode (START) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Appendix B: Gas Select Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Entering Gas Select Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Tips for Using Gas Select Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Saving the Alarm Points (SAVE-AP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Turning the Calibration Max Span On/Off (MAX.SPAN) . . . . . . . . . . . . . . . . . . . . . . . . 95
Stealth and Vibrator Settings (STEALTH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Exiting Gas Select Mode (START). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97
WARNING: Understand manual before operating. This is an intrinsically safe product.
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%).
AVERTISSEMENT: Comprendre le manuel avant de l'utiliser. Ceci est un produit
intrinsèquement sûr. La substitution de composants peut nuire à la
sécurité intrinsèque. Pour éviter l'inflammation d'une atmosphère
dangereuse, les batteries ne doivent être remplacées ou chargées que
dans une zone non dangereuse. Non testé dans des atmosphères
enrichies en oxygène (plus de 21%).

CO-04 Operator’s Manual Chapter 1: Introduction • 7
Chapter 1: Introduction
Overview
This chapter briefly describes the CO-04 gas monitor. This chapter also describes the
CO-04 Operator’s Manual (this document). Table at the end of this chapter lists the
specifications for the CO-04.
About the CO-04
Using an advanced detection system, the CO-04 personal gas monitor detects the presence of
carbon monoxide (CO). The CO-04’s compact size and easy-to-use design make 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 CO-04 offers a full range of features, including:
• Liquid crystal display (LCD) for complete and understandable information at a glance
• Ultrabright alarm LED
• Distinctive audible/vibrating alarms for dangerous gas conditions and audible alarms for
unit malfunction
• Microprocessor control for reliability, ease of use, and advanced capabilities
• Data logging functions
• Alarm trend data
• STEL, TWA, and over range alarms
• Peak reading
• Built-in time function
• Lunch break feature
• QPS “C/US” classification for Class I, Division I, Groups A, B, C, and D hazardous
atmospheres
WARNING: The Model CO-04 detects elevated levels of carbon monoxide which can be
dangerous or life threatening. When using the CO-04, you must follow the
instructions and warnings in this manual to assure proper and safe operation of
the unit and to minimize the risk of personal injury. Be sure to maintain and
periodically calibrate the CO-04 as described in this manual.

8• Chapter 1: Introduction CO-04 Operator’s Manual
AVERTISSEMENT: Le modèle CO-04 détecte les niveaux élevés de monoxyde de carbone qui
peuvent être dangereux ou mettre la vie en danger. Lorsque vous utilisez
le CO-04, vous devez suivre les instructions et les avertissements de ce
manuel pour assurer un fonctionnement correct et en toute sécurité de
l'appareil et pour réduire les risques de blessures. Assurez-vous de
maintenir et d’étalonner périodiquement le CO-04 comme décrit dans ce
manuel.
Specifications
Table 1: Standard Sensor Specifications/Alarm Points
Detection Range 0 - 2,000 ppm
Lowest Detectable Limit
(LDL)
3 ppm
Reading Increment 0 - 300 ppm: 1 ppm
310 - 2,000 ppm: 10 ppm
Warning Factory Setting 25 ppm
Alarm Factory Setting 50 ppm
Alarm H Factory Setting 1,200 ppm
STEL Alarm 200 ppm
TWA Alarm 25 ppm
Indication Accuracy
• 0 - 500 ppm: ± 5% of reading or ± 5 ppm
CO (whichever is greater)
• 510 - 2,000ppm: ± 20% of reading
Table 2: CO-04 Specifications
Sampling
Method
Diffusion
Response
Time
T90 Within 10 Seconds
Display Graphics LCD Display
Operating
Temperature
& Humidity
Continuous environment: -20°C to 50°C/10 to 90% RH
Temporary environment (up to 15 minutes): -40°C to 60°C/0 to 95% RH

CO-04 Operator’s Manual Chapter 1: Introduction • 9
Safety/
Regulatory
• ATEX: Certificate Number DEKRA 19ATEX0097
II 1G Ex ia IIC T4 Ga (with alkaline batteries)
II 1G Ex ia IIC T3, Ga (with Ni-MH batteries)
• IECEx: Certificate Number IECEx DEK 19.0059
Ex ia IIC T4 Ga (with alkaline batteries)
Ex ia IIC T3 Ga (with Ni-MH batteries)
• QPS classified, “C/US”, as Intrinsically Safe. Exia. Class I, Groups A, B, C, & D.
Instrument
Power
Information
• Operating Voltage: 3.0V
• Operating Current: 1.0 mA
• Operating Power: 3.0 mW
Power Supply
2 AAA alkaline batteries; 1.5V, 1.175 AH (Duracell MN2400 or PC2400)
OR
2 AAA Ni-MH batteries; 1.2V, 800 mAH (Panasonic Eneloop BK-4MCC)
Continuous
Operating
Hours
@ 25 °C
Alkaline Batteries: 9,000 hours in Measuring Mode (Non Alarm Operation, Fully
Charged)
Ni-MH Batteries: 6,000 hours in Measuring Mode (Non Alarm Operation, Fully
Charged)
Case High-impact Plastic, RF Shielded, Dust and Weather Proof (IP67)
Standard
Accessories
• Alligator clip
• Rubber boot
Optional
Accessories
•Beltclip
• Calibration cup
• Datalogging and Setup Programs (Windows®7, 8, and 10), available at
www.rkiinstruments.com/04series
• IrDA/USB Cable for connecting to a computer when using the Datalogging and
Setup Programs (not needed if computer has an infrared port)
Dimensions
and Weight
Approximately 67(H) x 54(W) x 24(D) mm (2.6”H x 2.1”W x 0.9”D)
Approximately 93 g (3.3 oz.)
Table 2: CO-04 Specifications

10 • Chapter 1: Introduction CO-04 Operator’s Manual
About this Manual
The CO-04 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.

CO-04 Operator’s Manual Chapter 2: Description • 11
Chapter 2: Description
Overview
This chapter describes the CO-04 instrument and its accessories.
Instrument Description
Case
The CO-04’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 water resistant.
A clear plastic window is located on the front of the case for viewing the LCD. The sensor
retainer is located on the right side of the case and allows access to the filters and sensor. A feature
in the lower left corner of the rear case is used to install the optional wrist strap.
LCD
A digital LCD (liquid crystal display) is visible through a clear plastic window in the top case.
The LCD shows the gas reading. The LCD also shows information for each of the CO-04’s
operating modes.
Battery Cover
Battery Cover Screw
IrDA Port
Buzzer Opening
LCD
Wrist Strap
Connection
Control Buttons
CO
AIR POWER
MODE
Alarm LED
Diffusion Port
Figure 1: Component Location

12 • Chapter 2: Description CO-04 Operator’s Manual
Control Buttons
Two control buttons, AIR and POWER MODE, are located below the LCD.
Alarm LED
The alarm LED above the sensor and buzzer openings alerts you to gas, low battery, and failure
alarms.
Buzzer
One solid-state electronic buzzer is located inside the case. Sound exits the case through a hole in
the upper left corner of the front case. The buzzer sounds for gas alarms, malfunctions, and low
battery voltage. It also provides feedback for button presses and while in Display, User,
Maintenance, or Gas Select Mode.
Vibrator
A vibrating motor inside the CO-04 case vibrates for gas alarms and unit malfunctions.
NOTE: If STEALTH is set to ON, the vibrator only functions when VIB in the STEALTH Gas
Select Mode item is set to ON (see page 96).
Table 3: CO-04 Control Button Functions
Button Function(s)
AIR • turns on LCD backlight
• resets alarm condition if LATCH is set to ON in Maintenance Mode
• enters User Mode, Maintenance Mode, and Gas Select Mode when
used with POWER MODE
• activates the demand zero function (adjusts the CO-04’s fresh air
reading)
• changes the value of a parameter available for adjustment
• scrolls through parameter options
POWER MODE • turns the CO-04 on and off
• turns on LCD backlight
• enters and scrolls through Display Mode
• enters instructions into the CO-04’s microprocessor
• resets alarm condition if LATCH is set to ON in Maintenance Mode
• enters User Mode, Maintenance Mode, and Gas Select Mode when
used with AIR

CO-04 Operator’s Manual Chapter 2: Description • 13
Sensor
The CO sensor is an electrochemical cell that consists 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 CO-04’s circuitry amplifies the current, converts the current
to a gas concentration, and displays the concentration on the LCD.
Filters
Charcoal Filter (Black)
A black charcoal filter is placed into a recess in the sensor gasket over the CO sensor. The
charcoal filter disk scrubs H2S and certain hydrocarbons out of the sample to avoid false CO
readings. If false or elevated CO readings are noticed, especially in the presence of H2S, change
the charcoal filter.
Hydrophobic Filter
The white, circular hydrophobic filter fits into a recessed area in the front case and is held in place
by the sensor gasket. It prevents water and particulates from entering the instrument.
Infrared Communications Port
An infrared (IR) communications port is located at the top of the instrument, near the LED.
Logged data transmits through the port in standard IrDA protocol. A computer’s infrared port or
an IrDA/USB cable connected to a USB port can be used to download data to the 04 Series
Datalogging Program. See the 04 Series Datalogging Program operator’s manual for data logging
and downloading instructions.
Batteries
2 AAA batteries (alkaline or Ni-MH) power the CO-04. At 25°C alkaline batteries will last at
least 9,000 hours (375 days) and Ni-MH batteries will last at least 6,000 hours (250 days). The
battery icon in the upper right of the LCD shows remaining battery life.
A low battery warning activates when the CO-04 detects a low battery voltage. The CO-04 sounds
a dead battery alarm when battery voltage is too low for Measuring Mode.
WARNING: Use only Duracell MN2400 or PC2400 or Eneloop BK-4MCC batteries to
maintain the QPS classification of the CO-04. Use of other batteries will void the
QPS classification and may void the warranty. Do not mix old/new or different
types of batteries.
AVERTISSEMENT: Utiliser uniquement des piles Duracell MN 2400 ou PC 2400 ou
Eneloop BK-4MCC de maintenir la classification QPS de la CO-04.
L’utilisation d’autres piles annule la classification QPS et peut annuler
la garantie. Ne mélangez pas les anciennes/nouvelles ou différents types
de piles.

14 • Chapter 2: Description CO-04 Operator’s Manual
WARNING: To prevent ignition of a hazardous atmosphere, the batteries must only be
changed in an area known to be nonhazardous.
AVERTISSEMENT: Pour éviter l'inflammation d'une atmosphère dangereuse, la batterie ne
doit être remplacée que dans une zone non dangereuse.
Standard Accessories
Alligator Clip
An alligator clip installs to 2 spring bars on the rear case. Use the alligator clip to attach the CO-
04 to clothing or a belt. Teeth in the alligator clip’s jaws prevent slipping. The alligator clip can be
rotated to change the instrument’s orientation.
Protective Rubber Boot
A protective rubber boot is installed over the CO-04.
Open
Alligator Clip
Closed
Figure 2: Alligator Clip
Side Front
Figure 3: Rubber Boot

CO-04 Operator’s Manual Chapter 2: Description • 15
Optional Accessories
Belt Clip
The belt clip installs to 2 spring bars on the rear case and is used to easily clip the CO-04 onto a
belt.
Wrist Strap
The wrist strap connects to a feature on the back case.
Calibration Cup
The calibration cup installs over the sensor. You must use the calibration cup when performing a
bump test, calibration, or gas test.
IrDA/USB Cable
Unless your computer has a built-in IrDA port, a IrDA/USB cable is needed to establish
communication between the CO-04 and the Datalogging Program or the Setup Program.
Belt Clip
Figure 4: Belt Clip
Figure 5: Calibration Cup

16 • Chapter 3: Measuring Mode CO-04 Operator’s Manual
Chapter 3: Measuring Mode
Overview
This chapter explains how to use the CO-04 to perform confined space entry monitoring or
general area monitoring in Measuring Mode.
Start Up
This section explains how to start up the CO-04, get it ready for operation, and turn it off.
Turning On the CO-04
To illustrate certain functions, the following description of the CO-04 start up sequence assumes
that the following items in User Mode are turned on: LUNCH, CAL.RMDR, and BP.RMDR in
User Mode, and ID DISP and A.ZERO in Maintenance Mode. If any of these items are turned
off, then the corresponding screens do not appear.
1. Press and briefly hold down POWER MODE. Release the button when you hear a beep.
2. If LUNCH is set to ON (factory setting if OFF, see page 62), the Lunch Break Screen
appears. The unit counts down from 5 seconds.
a. Continue Accumulating: To continue accumulating peak and time-weighted average
(TWA) readings from the last time the CO-04 was used, press and release POWER
MODE or allow the countdown to reach 0. The short-term exposure limit (STEL) reading
is reset each time the CO-04 is turned on.
b. Reset Accumulation: To reset the accumulation of peak and time-weighted average
(TWA) readings, press and release AIR before the countdown reaches 0.
5
SEC
RESUME
5
SEC
YES .MODE
5
SEC
NO .AIR

CO-04 Operator’s Manual Chapter 3: Measuring Mode • 17
3. If CAL.RMDR is set to ON (factory setting) and a calibration is due, the screen that appears
next depends on how CAL.EXPD is set in User Mode (see page 55). The three possible
screens are described below. If a calibration is not due, the instrument displays the number of
days left until a calibration is due.
CAL.EXPD set to
CONFIRM (factory setting)
CAL.EXPD set to
CANT.USE
CAL.EXPD set to
NONE
LCD
Sound Buzzer sounds double pulsing
tone
Buzzer sounds double pulsing
tone
None
Action • Option A, Perform
calibration: Press and
release POWER MODE to
enter User Mode and
perform a calibration. The
instrument takes you
straight to the calibration
start screen in User Mode’s
GAS CAL\A-CAL(E-CAL)
item (if Password
Protection is set to On
using the 04 Series Setup
Program, you must enter a
password first). See page 43
for calibration instructions.
If the calibration is
successful, the screen above
will not appear again until
the unit is due for
calibration. If the calibration
is not successful, the screen
above will again appear in
the startup sequence.
• Option B, Bypass message:
To continue without
performing a calibration,
press and release AIR.
The CO-04 cannot be used
until a successful calibration is
performed. Press and release
POWER MODE to enter User
Mode and perform a calibra-
tion. The instrument takes you
straight to the calibration start
screen in User Mode’s GAS
CAL/A-CAL
(E-CAL) item (if Password
Protection is set to On using
the 04 Series Setup Program,
you must enter a password
first). If you don’t press
POWER MODE, the instru-
ment automatically goes to the
calibration start screen after 6
seconds (if Password Protec-
tion is set to On using the 04
Series Setup Program, you
must enter a password first).
See page 43 for calibration
instructions.
If the calibration is successful,
the screen above will not
appear again until the unit is
due for calibration. If the cali-
bration is not successful, the
screen above will again appear
in the startup sequence.
• Option A, Perform
calibration: If you want to
enter User Mode and
perform a calibration, press
and release POWER
MODE. The instrument
takes you straight to the
calibration start screen in
User Mode’s GAS CAL/A-
CAL (E-CAL) item (if
Password Protection is set
to On using the 04 Series
Setup Program, you must
enter a password first).
• Option B, Bypass message:
To continue without
performing a calibration,
wait a few seconds for the
instrument to continue with
its startup sequence.
CAL
CAL - LMT
FAIL
CAL - LMT
0
d
NEXT .CAL

18 • Chapter 3: Measuring Mode CO-04 Operator’s Manual
4. If BP.RMDR is set to ON (factory setting is OFF) and a bump test is due, the screen that
appears next depends on how BP.EXPD is set in User Mode (see page 59). The three possible
screens are described below. If a bump test is not due, the instrument displays the number of
days left until a bump test is due.
BP.EXPD set to
CONFIRM (factory setting)
BP.EXPD set to
CANT.USE
BP.EXPD set to
NONE
LCD
Sound Buzzer sounds double pulsing
tone
Buzzer sounds double pulsing
tone
None
Action • Option A, Perform bump
test: Press and release
POWER MODE to enter
User Mode and perform a
bump test. The instrument
takes you straight to the
bump test start screen in
User Mode’s BUMP item (if
Password Protection is set
to On using the 04 Series
Setup Program, you must
enter a password first). See
page 41 for bump test
instructions.
If the bump test is
successful, the screen above
will not appear again until
the unit is due for bump
testing. If the bump test is
not successful, the screen
above will again appear in
the startup sequence.
• Option B, Bypass message:
To continue without
performing a bump test,
press and release AIR.
The CO-04 cannot be used
until a successful bump test is
performed. Press and release
POWER MODE to enter User
Mode and perform a bump
test. The instrument takes you
straight to the bump test start
screen in User Mode’s BUMP
item (if Password Protection
is set to On using the 04
Series Setup Program, you
must enter a password first).
If you don’t press POWER
MODE, the instrument auto-
matically goes to the bump
test start screen after 6 sec-
onds (if Password Protec-
tion is set to On using the 04
Series Setup Program, you
must enter a password first).
See page 41 for bump test
instructions.
If the bump test is successful,
the screen above will not
appear again until the unit is
due for bump testing. If the
bump test is not successful,
the screen above will again
appear in the startup
sequence.
• Option A, Perform bump
test: If you want to enter
User Mode and perform a
bump test, press and release
POWER MODE. The
instrument takes you
straight to the bump test
start screen in User Mode’s
BUMP item (if Password
Protection is set to On
using the 04 Series Setup
Program, you must enter a
password first).
• Option B, Bypass message:
To continue without
performing a bump test,
wait a few seconds for the
instrument to continue with
its startup sequence.
CAL
BP - LMT
FAIL
BP - LMT
0
d
NEXT .BP

CO-04 Operator’s Manual Chapter 3: Measuring Mode • 19
5. The Date/Time Screen appears for a few seconds.
6. The Battery Voltage Screen appears for a few seconds. An “AL-L” at the bottom of the screen
indicates that the alarms are set to latching. An “AL-A” at the bottom of the screen indicates
that the alarms are set to auto reset. See page 86 for a description of how to change this
parameter.
7. The following screens display for 1 second each: Gas Name, Full Scale, Warning Setpoint,
Alarm Setpoint, Alarm H Setpoint, STEL Setpoint, and TWA Setpoint.
8. If ID DISP is set to ON (factory setting is OFF, see page 88), the User ID Screen appears for
a few seconds, followed by the Station ID Screen.
2020
4.21
10:40
batt
2.8
AL -L
v
CO
2000
F . S .
ppm
CO
25
WARNING
ppm
CO
ppm
CO
50
ALARM
ppm
CO
1200
ALARM H
ppm
CO
200
STEL
ppm
CO
25
TWA
ppm
USER
ID
U_ID_001
STN
ID
S_ID_001

20 • Chapter 3: Measuring Mode CO-04 Operator’s Manual
9. If the CO-04 experiences a sensor failure during start up, a screen indicating that the sensor
failed appears and the buzzer sounds a double pulsing tone once per second.
You cannot acknowledge the failure and continue to Measuring Mode. Replace the failed
sensor as soon as possible.
10. If A.ZERO is set to ON (factory setting is OFF, see page 87), the instrument prompts you to
do an auto zero. An auto zero operation sets the reading to 0 ppm.
WARNING: Make sure that the instrument is in a known fresh air environment (an
environment free of combustible or toxic gases and of normal oxygen
content, 20.9%) before performing an auto zero operation. If you perform an
auto zero operation in an area with gases present, the adjustment will not be
accurate.
You must press and release the POWER MODE button to perform an auto zero function. If
you do not press any key, after 15 seconds, the instrument enters Measuring Mode without
performing an auto zero.
If Password Protection is turned On (factory setting is Off) using the 04 Series Setup
Program, a user-set password is required to perform an auto zero. When the password
screen appears, adjust each digit with the AIR button and press and release the POWER
MODE button to move on to the next digit. Once the password is entered, the instrument
performs the auto zero.
11. The CO-04 is now monitoring for gas in Measuring Mode. The Measuring Mode Screen
displays the current gas reading.
CO
FAIL
SENSOR
ppm
A .ZERO YES .MODE NO .AIR
0000
PASS-W
CO
0
ppm