RKI Instruments GasWatch 1 User Manual
Instruction Manual
GasWatch
Portable T wo-Gas Monitor
Part Number: 71-0031RK
Edition: First
Released: January 1998
RKI Instruments, Inc. • 33248 Central Ave, Union Ciy, CA 94587 • (510) 441-5656
.
Warranty
RKI Instruments, Inc., warranties gas alarm equipment manufactured by RKI and sold by
RKI to be free from defects in materials and workmanship for a period of one year from
date of shipment from RKI Instruments, Inc. Any parts found defective within that period
will be repaired or replaced, at our option, fr ee of char ge. This warranty does not apply to
items that are subject to deterioration or consumption in normal service, and which must
be cleaned, repaired, or replaced routinely. Those items include, but are not limited to:
absorbent cartridges filter elements
pump diaphragms and valves batteries
lamp bulbs and fuses
This warranty is voided by mechanical damage, misuse, alteration, rough handling, or
repairs not in accordance with the operator’s manual. This warranty indicates the full
extent of our liability. We are not responsible for removal or r eplacement costs, local r epair
costs, transportation costs, or contingent expenses incurred without our prior approval.
T
HIS
WARRANTY
EXPRESSED
I
NSTRUMENTS
MERCHANTABILITY
I
NSTRUMENTS
DAMAGE
PRODUCTS
OF
OR
IMPLIED
, I
, I
ANY
TO
FUNCTION
IS
IN
NC
.,
INCLUDING
OR
NC
.,
BE
KIND
LIEU
OF
ANY
,
AND
ALL
FITNESS
CONNECTED
LIABLE
OR
OPERATE
FOR
FOR
OTHER
OTHER
BUT
A
INDIRECT
WITH
NOT
WARRANTIES
OBLIGATIONS
LIMITED
PARTICULAR
,
INCIDENTAL
THE
USE
PROPERLY
OR
TO
THE
PURPOSE
OF
ITS
AND
REPRESENTATIONS
LIABILITIES
WARRANTY
. I
N
NO
EVENT
,
OR
CONSEQUENTIAL
PRODUCTS
OR
ON
OF
THE
PART
SHALL
FAILURE
,
RKI
LOSS
OF
OF
ITS
RKI
OR
This warranty covers instruments and parts sold to end users by authorized distributors,
dealers, and representatives of RKI Instruments, Inc.
We do not assume indemnification for any accident or damage caused by the operation of
this gas monitor. Our warranty is limited to replacement of parts or our complete goods.
ii • Warranty GasWatch Instruction Manual (Two-Gas)
Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Display Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Alarm Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Control Buttons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Wrist Strap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Normal Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Displaying Peak Readings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Adjusting the Alarm Points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Setting the Time and Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Responding to Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Supplies and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Assembling the Calibration Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Calibrating the GasWatch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Disassembling the Calibration Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Replacing Components of the GasWatch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Arm Strap. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
GasWatch Instruction Manual (Two-Gas) Table of Contents • iii
iv GasWatch Instruction Manual (Two-Gas)
or
Introduction
The GasWatch is a portable gas monitoring device. It is offered in single-gas and two-gas
versions. This instruction manual describes the two-gas version. The GasWatch is
compact, convenient, and offers a full range of features, including:
• detection of oxygen deficiency and carbon monoxide or hydrogen sulfide
• LCD display for complete, understandable information at a glance
• distinctive audible alarms for dangerous gas conditions and malfunctions
• designed for intrinsic safety for Class I, Groups A, B, C, and D hazar dous atmospher es
• microprocessor control for reliability, ease of use, and advanced capabilities
• small size and light weight for user comfort
• wrist strap or
optional arm strap for hands-free gas monitoring
W ARNING: The GasW atch is designed to detect oxygen deficiency and carbon monoxide
hydrogen sulfide, which can be life threatening. Users must follow the
instructions and warnings in this manual to assure proper and safe
operation of the GasWatch.
Specifications
Table 1: Specifications
CX-GW HX-GW
Target Gases Carbon monoxide (CO); Oxygen (O2) Hydrogen sulfide (H2S); Oxygen (O2)
Detection Range
Alarm Point
Display Increment
Sampling Method Diffusion Diffusion
Response Time
CO: 0 to 500 ppm; O2: 0 to 40.0% vol. H2S: 0 to 150.0 ppm; O2: 0 to 40.0% vol.
CO: 25 ppm;
O2: 19.5% vol. (dec.);23.5% vol. (inc.)
CO: 1 ppm; O2: 0.1% vol.
CO: T90 in 30 sec.; O2: T90 in 20 sec.
O2: 19.5% vol. (dec.);23.5% vol. (inc.)
H2S: 0.5 ppm; O2: 0.1% vol.
H2S: T90 in 30 sec.; O2: T90 in 20 sec.
H2S: 10 ppm;
Accuracy
CO: ± 5 ppm (up to 150 ppm);
O2: ± 0.5% vol.
H2S: ± 1.5 ppm (up to 30 ppm);
O2: ± 0.5% vol.
Dimensions 3.1 in. x 3.3 in. x 1.2 in. (7.9 cm x 8.4 cm x 3.0 cm)
Weight 6 ounces (170.1 grams)
Battery life
1
Oper. Temperature 14 °
720 hours
F to 104 ° F (-10 ° C to 40 ° C)
Humidity (max.) 85% RH (non-condensing)
1
(based on continuous operation without alarms or use of back light feature)
GasWatch Instruction Manual (Two-Gas) Introduction • 1
Description
This section describes components of the GasWatch.
Sensors
The two-gas version of the GasWatch includes two of the following sensors (see Table 1).
The sensors are above the display screen. Labels indicate the target gas of each sensor
(CO, H
monitoring environment. The sensor and dust cover are secured by the sensor retainer.
Carbon monoxide and hydrogen sulfide sensor
S, or O
2
). A dust cover protects each sensor from harmful objects in the
2
The CO and H
electrodes in an acid electrolyte. A gas permeable membrane covers the cell and allows
gas in the monitoring environment to diffuse into the electrolyte at a rate proportional to
its partial pressure. The gas reacts in the cell and produces a current proportional to the
concentration of the target gas. The current is amplified by the GasWatch’s circuitry,
converted to a measurement of gas concentration, and displayed on the display screen.
Oxygen sensor
The O
alkaline electrolyte. A fluorocarbon membrane covers the cell and allows gas in the
monitoring environment to diffuse into the electrolyte at a rate proportional to the partial
pressure of oxygen. The oxygen reacts in the cell and produces a current proportional to
the concentration of oxygen. The current develops a voltage across a temperaturecompensating thermistor/resistor network. The voltage is measured by the GasWatch’s
circuitry, converted to a measurement of gas concentration, and displayed on the display
screen.
sensor is an electrochemical cell that consists of gold and lead electrodes in an
2
S sensors are electrochemical cells that consist of three precious metal
2
Display Screen
During normal operation the display screen displays the current concentration of one of
the target gases and the time of day. To display the second target gas, press the DISP
button.
You can also display and/or adjust peak readings, time-weighted averages, alarm points,
date, and time. See “Operation” on page 5 for more information. The GasW atch includes a
back light feature so you can see the display screen in dimly-lit environments.
Alarm Light
The alarm light is above and to the right of the display screen. The alarm light is a red LED
that alerts you to gas, low battery, and sensor failure alarms.
2 • Description GasWatch Instruction Manual (Two-Gas)
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