RKI Instruments GasWatch 2 User Manual

GasWatch 2

Operator’s Manual

Part Number: 71-0065RK
Revision: F
Released: 2/2/11

www.rkiinstruments.com

WARNING

Read and understand this instruction manual
before operating instrument. Improper use of the
gas monitor could result in bodily harm or death.

Periodic calibration and maintenance of the gas
monitor is essential for proper operation and cor­rect readings. Please calibrate and maintain this
instrument regularly! Frequency of calibration
depends upon the type of use you have and the
sensor types. Typical calibration frequencies for
most applications are between 1 and 3 months,
but can be required more often or less often
based on your usage.

GasWatch 2 Operator’ s Manual

Warranty

RKI Instruments, In c. warrants the GasWatch 2 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. 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:

Absorbent cartridges
Filter elements, disks, or sheets
Pump diaphragms and valves

Warranty is voided by abuse including mechanical damage, alteration,
rough handling, o r r epair procedures not in accordance w i th t he instruction
manual. This warranty indicates the full extent of our liability, and we are
not responsible for removal or replacement costs, local repair costs,
transportation costs, or contingent expenses incurred without our prior
approval.

THIS WARRANTY IS EXPRESSLY IN LIEU OF ANY AND ALL OTHER WARRANTIES

AND REPRESENTATIONS, EXPRESSED OR IMPLIED, AND ALL OTHER OBLIGATIONS
OR LIABILITIES ON THE PART OF RKI INSTRUMENTS, INC. INCLUDING BUT NOT
LIMITED TO THE WARRANTY OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE. 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 indemn ification 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.

GasWatch 2 Operator’s Manual Warranty

Table of Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Wristband . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Sensor Cap/.Sensor Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Charcoal Filter Disk in GW-2C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

LCD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Control Buttons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Printed Circuit Boards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Alarm Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Buzzer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Vibrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Lithium Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Start Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Start-up Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Performing a Fresh Air Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Turning Off the GasWatch 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Measuring Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Displaying the Peak, STEL, & TWA (GW-2C & GW-2H) . . . . . . . . . . . . . . . . . . 11

Displaying Min and Max (GW-2X). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Displaying and Setting the Alarm Points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Setting the Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Setting the Fresh Air Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Setting the Span (Zero for GW-2X). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table of Contents GasWatch 2 Operator’ s Manual

Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Replacing the Lithium Battery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Replacing the Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Replacing the Sensor Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Replacing the Charcoal Filter Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Replacing the Wristband. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Appendix A: MRI Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

WARNING: Understand manual before operating. Substitution of

components may impair intrinsic safety. To prevent
ignition of a hazardous atmosphere, batteries must only
be changed in an area known to be nonhazardous. Not
tested in oxygen en riched atmospheres (abo ve 21%).

GasWatch 2 Operator’s Manual Table of Contents

Introduction

Using an advanced microprocessor controlled detection system, the
GasWatch 2 Personal Single-Gas Monitor detects the presence of either
carbon monoxide (CO), hydrogen sulfide (H2S), or oxygen (O2). The

GasWatch 2’ s comp act size and easy-to-use design make s it ideally suited
for a wide range of applications, including sewage treatment plants,
tunnels, hazardous waste sites, petrochemical facilities, oil fields, mines,
and chemical plants. The GasWatch 2 is even small enough to be worn
comfortably o n the wris t like a watch. The GasWatch 2 offers a full rang e of
features, including:

• Hands free gas monitori n g

• Compact “watch type” design

• Fast, accurate response with digital liquid crystal display (LCD)

• Visual, audible, and vibration alarms

• Microprocessor control for reliability, ease of use, and advanced
capabilities

• Peak, STEL, and TWA indication for GW-2C & GW-2H

• Minimum and maximum indication for GW-2X

• STEL, TW A, an d ov er ran ge al ar m s

• Sensor fail alarm

• Displays current time

• Over 3,000 hours of operation from 1 battery

• CSA classified for Class I, Division I, Groups A, B, C, and D hazardous
atmospheres

WARNING: The GasWatch 2 detects carbon monoxide, hydroge n

sulfide, or oxygen deficiency and elevated levels of
oxygen, all of which can be dangerous or life threatening.
When using the GasWatch 2, 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 calibrate
the GasWatch 2 as described in this manual.

1 • Introduction GasWatch 2 Operator’s Manual

Specifications

Table 1: GasWatch 2 Specifications

GW-2C GW-2H GW-2X

Target Gas Carbon Monoxide

(CO)

Hydrogen Sulfide

(H2S)

Oxygen

(O2)

Detection Range 0 to 500 ppm 0 to 100.0 ppm 0 to 40.0% vol.

Display Increment 1 ppm 0.5 ppm 0.1% vol.

Detection

Electro Chemic al Electro Chemic al Galvanic Cell

Principle

Alarm Points Low 25 ppm

High 50 ppm

TWA 25 ppm

STEL 200 ppm

Low 10.0 ppm
High 30.0 ppm

TWA 10.0 ppm
STEL 15.0 ppm

Low 19.5% vol.

(decreasing)

High 23.5% vol.

(increasing)

Sampling Method Diffusion Diffusion Diffusion

Response Time T90 in 30 seconds T90 in 30 seconds T90 in 20 seconds

Accuracy ± 5% of reading or

± 5 ppm CO

(whichever is

greater)

± 5% of reading or

± 2 ppm H2S

(whichever is

greater)

± 0.5% O

2

Safety/Regulatory

C US

186718

CSA classified, “C/US”, as Intrinsically Safe. Exia. Class I,

Groups A, B, C, & D. Class I, Zone 0, Group IIC.

Temperature Code T4.

Power Tw o AAA size Alka line Batte ries Standard, Duracell M N2400

or PC2400, Eveready Energizer E92 or EN92

Continuous

Approximately 3,000 Hours With No alarms or Backlighing

Operating Hours

Case High-impact Plastic, Dust Proof and Weather Resistant

Standard

Wristband

Accessory

GasWatch 2 Operator’s Manual Specifications • 2

Table 1: GasWatch 2 Specifications

GW-2C GW-2H GW-2X

Optional

Accessories

Dimensions and

Weight

Operating T emp. &

Humidity

• Belt Clip

• Hard Hat Clip

• Lapel Clip
Dimensions: 2.5 (H), 1.7 (W), 0.9 (D) inches

Weight: 2 oz.

-10°C - 40°C, below 85% RH (non condensing)

3 • Specifications GasWatch 2 Operator’ s Manual

Description

This section describes the components of the GasWatch 2. These
components include the GasWatch 2’s case, wristband, sensor cap and
sensor cover, charcoal filter disk (in the GW-2C), sensor, LCD, control
buttons, printed circuit boards, alarm lights, buzzer, vibrator, and lithium
battery.

Alarm LED Lens

Buzzer Opening

POWER

MODE

Wristband

LCD Display Window

Sensor Diffusion
Port

AIR

Sensor Cap

Control Buttons

Figure 1:Components of the GasWatch 2

GasWatch 2 Operator’s Manual Description • 4

Case

The GasWatch 2’s sturdy, high -im pact plastic case is suitable for use in
many environmen ta l condit ions, in doors and out. The uni t is dust pr oof and
weather resistant. The case has two halves, the top case and the bottom
case. They are held together by four screws in the bottom case. The case
is a different color depe nding on the model. The GW-2C for CO is red, the
GW-2H for H2S is orange, and the GW-2 X for oxyg en is bl ue .

The digital LCD is visible through the top case. It displays gas
concentrations, battery level, time, and other readings including TWA,
STEL, and peak gas levels. Below the LCD are two black control buttons.
The button on th e left is labeled POWER/MODE. The b utto n on the right is
labeled AIR.

To the left of the LCD is the buzzer, which is located inside the unit. To the
right of the LCD is the sensor cap which retains the sensor. Above the LCD
is a frosted lens through which the alarm lights are visible.

A battery cover is located on the bottom case and is held in place by two
screws. The wristband attaches to the bottom case.

Wristband

The GasWatch 2 comes with a wristband as a standard accessory so the
unit may be worn as a watch and allow hands-free gas monitoring. The
wristband is held in place with the sam e type of spring ba rs that are used i n
a watch. The spring bars are protected by hollow tubes which fit into the
wristband. Optional accessories are available from RKI Instruments, Inc.
that can be used in place of the wristband such as a belt clip.

Sensor Cap/Sensor Cover

The sensor cap snaps onto the right side of the case and retains the
sensor. It also retains the sensor cover which is a round hydrophobic disk
membrane which protects the sensor from dirt and weather. A gasket
installed on the sensor seals against the sensor, sensor cover, and sensor
cap.

Charcoal Filter Disk in GW-2C

The GW-2C includes a charcoal filter disk which is located in a recessed
area of the sensor gasket be neath the sensor cove r . The charcoal fil ter disk
removes gases from the sampled air that will cause a response on the CO
sensor such as H2S and certain hydrocarbons. If false or elevated CO

readings are noticed, especial l y in the presence of H2S, change the
charcoal filte r disk (see the Maintenance section for instructions).

5 • Description GasWatch 2 Operator’s Manual

Sensor

The GasWatch 2 uses either an oxygen, CO, or H2S sensor . The sensor is
protected by the white sensor cover which is held in place by the sensor

cap and sensor gasket. The sensor cover allows ambient air to diffuse past
it to the sensor. The three sensors used in the three GasWatch 2 models
use different detection principles as described below.

Oxygen Sensor

The oxygen sensor is a galvanic type of sensor. A membrane covers the
cell and allows gas to diffuse i nto the cell at a rate proportion al to the par tial
pressure of oxygen. The oxygen react s in the cell and prod uce s a volta ge
proportion al to the concentration of oxygen. The voltage is measured by
the GasWatch 2’s circuitry, converted to a measurement of gas
concentration, and displayed on the LCD.

CO and H2S Sensors

The CO and H
precious metal electrodes in an 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 c urrent
proportional to the concentration of the target gas. The current is amplified
by the GasWatch 2’s circuitry, converted to a measurement of gas
concentration, and displayed on the LCD.

S sensors are electrochemical sensors that consist of two

2

LCD

The LCD is visible through the top case. Target gas concentrations, the
time, battery condition, and alarm indications are displayed on the LCD.
When either of the control buttons is pressed, the LCD backlight comes on
for 20 seconds.

Control Buttons

Below the LCD are the two control buttons. They are POWER/MODE and
AIR. They turn on the power to the GasWatch 2 and turn it off. They control
what is displayed on the LCD, including ti me, gas concentrations, peak,
TWA, and S TEL re adin gs, as well as othe r messag es. They a lso allow yo u
to perform a fresh air adjustment, change alarm points, change the time,
and calibrate the instrument. The functions performed by the control
buttons are summarized in the following table:

GasWatch 2 Operator’s Manual Description • 6

Table 2: The Control Buttons of the GasWatch 2

Button Function

• Turns the unit on and off.

• Turns the LCD back light on.

• Displays STEL and TWA readings (GW-2H & GW­2C).

• Displays peak readings (high for GW-2H & GW-2C

POWER/MODE

and low & high for GW-2X).

• Resets the alarm circuit (gas alarms).

• Enters Calibration Mode with the AIR button.

• Enters Alarm Adjustment Mode with the AIR
button.

• Enters Time Adjustment Mode with the AIR button.

• Turns the LCD back light on.

• Adjusts LCD r eadings w hen a fresh air adju stment
is performed.

• Enters Calibration Mode with the POWER/MODE
button.

AIR

• Enters Alarm Adjustment Mode with the POWER/
MODE button.

• Enters Time Adjustment Mode with the POWER/
MODE button.

• Increases settings when the unit is in Alarm
Adjustment Mode, Time Adjustment Mode, or
Calibration Mode.

Printed Circuit Boards

The primary function of the GasWatch 2’s two printed circuit boards are to
amplify the current or voltage signal sent to them from the gas sensor,
convert the signal to a meaningful measurement of gas concentration,
display the gas concentration on the LCD, store peak, STEL, and TWA
readings, and activate th e alarm cir cuit if an ala rm point h as been reac hed.
They monitor battery level, battery failure, and sensor failure. They also
control the GasW atch 2’ s time funct ion and the vari ous operati ng modes of
the unit.

NOTE: The printed circuit boards co ntain no user serviceab l e parts.

7 • Description GasWatch 2 Operator’s Manual