RKI Instruments GasWatch 1 User Manual

Instruction Manual
GasWatch
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)
Control Buttons
The control buttons are below the display screen.Table 2 lists the function of each button.
Table 2: GasWatch Button Functions
Button Function
MODE/POWER • turns GasWatch on and off
• turns display back light on and off
• displays peaks readings
• resets alarm circuit (gas alarms)
• enters calibration mode (with AIR button)
• enters alarm adjustment mode (with AIR button)
• enters time/date adjustment mode (with DISP button)
DISP • displays “second” target gas
• enters time/date adjustment mode (with MODE/POWER button)
AIR • adjusts the display reading to 0 (20.9 for O
• enters calibration mode (with MODE/POWER button)
• enters alarm adjustment mode (with MODE/POWER button)
)
2
Batteries
The GasWatch is powered by two zinc air batteries. The button-type batteries are installed in the battery compartment. You can access the battery compartment through a removable door in the back of the GasWatch. The batteries will run the GasWatch for approximately 720 hours of continuous operation without alarms or use of the display back light.
NOTE: Frequent alarms and use of the back light feature reduce the life span of the
batteries.
Zinc air batteries work by reacting with air. RKI Instruments, Inc., ships replacement batteries with a protective sticker, which covers the battery’s air diffusion holes. When the protective sticker is removed, the battery will last three months whether or not it is used. If the battery is used, it may last less than three months from the time you remove the sticker.
Wrist Strap
The wrist strap allows you to wear the GasWatch and leaves your hands free to perform other tasks. The wrist strap is attached to the back of the GasWatch and includes a velcro section to secure the GasWach during operation.
NOTE: Y ou can r eplace the wrist strap with an optional arm strap that you wear on your
upper arm. See “Accessories” on page 13 to install the arm strap.
GasWatch Instruction Manual (Two-Gas) Description • 3
Start Up
1. Press the POWER button until the alarm light turns on (approximately 3 seconds). The GasWatch temporarily tests all elements of the display screen, then displays the
battery voltage.
V
.
:
After several seconds, the GasWatch automatically displays the toxic gas normal screen (CO or H
S),
2
ppm
2S
H
.
:
then the GasWatch displays the oxygen normal screen. The GasWatch is in normal operation.
%
O2
.
:
Tip: You can test the oxygen sensor and alarm circuit by exhaling into the sensor. When
the display reading drops below the decreasing oxygen alarm point, the buzzer should sound, the display reading should flash, and the alarm light should turn on.
2. Press the AIR button for appr oximately 3 seconds to set the zero r eading (span for O The buzzer sounds a pulsing tone while it is adjusting the readings (0 for H
20.9 for O
). Continue pressing the AIR button until the pulsing tone stops.
2
2
2
S or CO;
3. Use the wrist strap to attach the GasWatch to your wrist. The wrist strap has a velcro section to ensure that the GasWatch remains secured to your wrist during operation. (See “Accessories” on page 13 to install the optional arm strap.
).
4 • Start Up GasWatch Instruction Manual (Two-Gas)
Operation
This section describes the GasWatch in normal operation. This section also describes procedures to display peak readings, and set the alarm points and time and date.
Normal Operation
The GasWatch continuously monitors the atmosphere and displays the concentrations present of one of the target gases.
Press the DISP button to display the second target gas.
Press the POWER/MODE button to turn on the display back light in dimly-lit areas.
Displaying Peak Readings
NOTE: For CO and H
readings represent the lowest reading. The GasW atch displays peak readings for the target gas that is currently displayed on the normal screen.
1. From the normal screen, press the MODE button. The back light turns on.
2. Press the MODE button again. The peak reading displays. This is the peak reading since the last time the GasWatch was turned on.
NOTE: The GasWatch does not display STEL or TWA readings for the oxygen sensor.
3. Press the MODE button again. The STEL reading displays. The STEL (short term exposure limit) r eading is the average gas reading over the past
15 minutes.
4. Press the MODE button again. The TWA reading displays. The TWA (time weighted average) reading is the average gas reading over the past
8 hours. If the GasWatch has been on less than 8 hours, it assumes the reading has been 0 during the period the GasWatch was turned off.
5. Press the MODE button again to return to the normal screen. The back light is off.
S, peak readings represent the highest reading. For O
2
, peak
2
Adjusting the Alarm Points
NOTE: When adjusting alarms points, the AIR button increases the setting, and the DISP
button decreases the setting.
1. Verify that the GasWatch is turned off. Only the time of day is displayed when the GasWatch is off. To turn off the GasWatch,
press the POWER button until only the time of day is displayed (approximately 5 seconds).
2. Press the MODE and AIR buttons simultaneously.
3. Release the AIR button when the GasWatch displays all display elements (approximately 1 second).
The GasWatch beeps, then the decreasing oxygen alarm point displays.
GasWatch Instruction Manual (Two-Gas) Operation • 5
4. Release the MODE button.
5. Adjust the alarm setting with the AIR and DISP buttons, then pr ess the MODE button. The increasing oxygen alarm point displays.
6. Adjust the alarm setting with the AIR and DISP buttons, then pr ess the MODE button. The toxic gas (H
S or CO) alarm point displays.
2
7. Adjust the alarm setting with the AIR and DISP buttons, then pr ess the MODE button. The toxic gas STEL alarm point displays.
8. Adjust the alarm setting with the AIR and DISP buttons, then pr ess the MODE button. The toxic gas TWA alarm point displays.
9. Adjust the alarm setting with the AIR and DISP buttons.
10. Press the MODE button to turn on the GasWatch. (See Start Up on page 4.)
Setting the Time and Date
1. Verify that the GasWatch is turned off. Only the time of day is displayed when the GasWatch is off. To turn off the GasWatch,
press the POWER button until only the time of day is displayed (approximately 5 seconds).
2. Press the MODE and DISP buttons simultaneously until the buzzer sounds (approximately 3 seconds). The time displays 000 , then the minutes setting ashes.
3. Press the DISP button to increase the minutes setting. You can only increase the setting. The setting returns to 0 after 59 displays.
4. Press the AIR button. The hours setting ashes.
5. Press the DISP button to increase the hours setting. You can only increase the setting. The setting returns to 1 after 12 displays.
6. Press the AIR button. The date setting ashes.
7. Press the DISP button to increase the date setting. You can only increase the setting. The setting returns to 1 after 31 displays.
8. Press the AIR button. The month setting ashes.
9. Press the DISP button to increase the month setting. You can only increase the setting. The setting returns to 1 after 12 displays.
10. Press the AIR button to verify the date setting.
11. Press the AIR button again to verify the time setting.
NOTE: T o adjust either setting, pr ess and release the AIR button until the minutes setting
ashes, then repeat steps 3 through 9.
12. Press the MODE button to turn on the GasWatch. (See Start Up on page 4.)
6 • Operation GasWatch Instruction Manual (Two-Gas)
Alarms
)
This section describes the GasWatchs gas, battery, and malfunction alarms. Table 3 lists the visual and audible indications for each type of alarm. (See T able 1, “Specifications,” on page 1 for the default gas alarm points.)
Table 3: GasWatch Alarm Indications
Alarm Type Visual Indications Audible Indication
Gas
(above alarm point; also below for O
1
Gas
(above STEL or TWA alarm point)
alarm light ashes
gas reading ashes
back light turns on
2
alarm light ashes
TWA or STEL flashes on
display screen
pulsing tone
pulsing tone
back light turns on
Over Range gas reading replaced by
double pulsing tone
over range/peak reading icon displays in lower left corner of screen
Low Battery battery icon displays
none
internal battery icon ashes
Battery Failure gas reading replaced by
double pulsing tone
FAIL
battery icon ashes
Sensor Failure
1
The oxygen sensor does not initiate STEL or TWA alarms.
2
If the oxygen sensor fails, the gas reading ashes 0.0% and the buzzer sounds a pulsing tone.
2
gas reading replaced by FAIL
double pulsing tone
NOTE: The GasWatch automatically displays the reading for the target gas that initiates
an alarm. For example, if the oxygen normal screen is displayed, and the toxic gas sensor initiates an alarm, the GasWatch automatically switches to the toxic gas screen.
Responding to Alarms
This section describes response to gas, over range, battery, and sensor failure alarms.
Responding to gas alarms
1. Determine which sensor is initiating the gas alarm.
2. Follow your established procedure for an increasing gas condition or decreasing oxygen condition.
3. When the display reading decrease below (or rises above for O point, press the MODE button to reset the alarm circuit. The alarm light turns off and
the buzzer silences.
GasWatch Instruction Manual (Two-Gas) Alarms • 7
sensor) the alarm
2
Responding to over range alarms
WARNING: An over range condition may indicate an extreme toxic gas or oxygen
content condition. Confirm a normal condition with a different GasWatch or other gas detection device.
1. Determine which sensor is initiating the over range alarm.
2. Calibrate the sensor as described on page 9.
3. If the over range condition continues, replace the sensor as described on page 12.
4. If the over range condition continues after you replace the sensor, contact RKI Instruments, Inc., for further instruction.
Responding to battery alarms
WARNING: The GasWatch is not operational as a gas monitoring device during a
battery failure alarm. Take the GasWatch to a non-hazardous area, and replace the battery as described on page 12.
The GasWatch is fully functional during a low battery alarm; however, the GasWatch has approximately 10 minutes of operating time remaining from the initial low battery alarm. Replace the battery as soon as possible as described on page 12.
NOTE: Other alarms and use of the back light feature reduce the amount of operating
time remaining.
Responding to sensor failure alarms
1. Determine which sensor is initiating the sensor failure alarm.
2. Calibrate the sensor as described on page 9.
3. If the sensor failure continues, replace the sensor as described on page 12.
4. If the sensor failure continues after you replace the sensor, contact RKI Instruments, Inc., for further instruction.
8 • Alarms GasWatch Instruction Manual (Two-Gas)
Calibration
This section describes how to prepare for calibration, calibrate the GasWatch, and return to normal operation. This section also describes equipment that is necessary to perform the calibration procedure.
Supplies and Equipment
To calibrate the GasWatch, you will need the following supplies and equipment. RKI calibration kits are available for this purpose (see Parts List on page 14).
For the toxic gas sensor (CO or H2S), known calibrating samples of the target gas. The samples should have concentrations in approximately the middle of the range of
detection.
For the oxygen sensor, an oxygen-free source, such as pure nitrogen or CO in a nitrogen balance
A xed-ow regulator, non-absorbent tubing, and calibration cup
Assembling the Calibration Kit
WARNING: Calibrate the GasWatch in a non-hazardous environment.
1. Attach the calibration tubing to the calibration cup, then attach the opposite end of the tubing to the regulator.
2. Slide the calibration cup over the toxic gas (CO or H2S) sensor.
NOTE: Do not attach the regulator to the gas cylinder at this time.
Calibrating the GasWatch
This section describes calibration of the toxic gas and oxygen sensors.
Calibrating the toxic gas sensor
1. Verify that the GasWatch is turned off. Only the time of day is displayed when the GasWatch is off. To turn off the GasWatch,
press the POWER button until only the time of day is displayed (approximately 5 seconds).
2. Press and hold the AIR and MODE buttons simultaneously until the GasWatch beeps and CAL displays (approximately 2 seconds).
The toxic gas calibration screen automatically displays.
3. Attach the regulator to the toxic gas cylinder. The xed-ow regulator automatically begins introducing the calibration sample to the toxic gas sensor.
GasWatch Instruction Manual (Two-Gas) Calibration • 9
4. Allow the display reading to stabilize (approximately 1 to 2 minutes), then use the AIR and DISP buttons to adjust the display reading to match the concentration of the calibration sample.
The AIR button increases the reading; the DISP button decreases the reading.
NOTE: If you cannot adjust the display reading to match the calibrating sample, replace
the toxic gas sensor as described on page 12.
5. Unscrew the regulator from the toxic gas cylinder. The display reading decreases.
6. Remove the calibration cup from the toxic gas sensor, then slide the cup over the oxygen sensor.
Calibrating the oxygen sensor
1. Press the MODE button. The oxygen calibration screen displays.
2. Attach the regulator to the oxygen-free gas cylinder. The xed-ow regulator automatically begins introducing the calibration sample to the oxygen sensor.
3. Allow the display reading to stabilize (approximately 1 to 2 minutes), then use the AIR and DISP buttons to adjust the display reading to match the oxygen concentration of the calibration sample.
The AIR button increases the reading; the DISP button decreases the reading.
NOTE: If you cannot adjust the display reading to match the calibrating sample, replace
the oxygen sensor as described on page 12.
4. Unscrew the regulator from the gas cylinder. The display reading increases.
5. When the display reading increases above the oxygen alarm point, press the MODE button to turn on the GasWatch. (See Start Up on page 4.)
Disassembling the Calibration Kit
1. Remove the calibration cup from the sensor. Leave the calibration cup and regulator connected by the sample tubing for convenience.
2. Place the calibration kit components in the storage case, and store in a safe and convenient place.
10 • Calibration GasWatch Instruction Manual (Two-Gas)
Maintenance
Troubleshooting
The troubleshooting guide describes symptoms, probable causes, and recommended action for problems you may encounter with the GasWatch.
Fail condition
Symptoms
CO/H2S: the gas reading is replaced by FAIL.
CO/H2S: the buzzer is sounding a double pulsing tone.
O2: the gas reading is 0.0% vol.
O2: the buzzer is sounding a pulsing tone.
Probable causes
The sensor is missing or not plugged in properly.
The sensor requires calibration.
The sensor is defective.
Recommended action
1. Determine which sensor is initiating the fail condition.
2. Verify the sensor is plugged in properly.
3. Calibrate the sensor as described on page 9.
4. If the fail condition continues, replace the sensor as described later in this section.
5. If the fail condition continues after you replace the sensor, contact RKI Instruments, Inc., for further instruction.
Slow or no response/difficult or unable to calibrate
Symptoms
Unable to accurately set the response reading during the calibration procedure.
The GasWatch requires frequent calibration.
NOTE: Under normal circumstances, the GasWatch requires calibration every 3
months. Some applications may require a more frequent calibration schedule.
Probable causes
The calibration cylinder is low, out-dated, or defective.
The sensor dust cover is dirty or clogged.
The sensor is defective or its sensitivity reduced due to age.
Recommended action
1. Verify that the calibration cylinder for the affected sensor contains an adequate supply of a fresh test sample.
2. Inspect the sensor dust cover for the affected sensor to make sure it is not dirty or clogged. If necessary, replace the cover as described on page 12.
GasWatch Instruction Manual (Two-Gas) Maintenance • 11
3. If the calibration/response difculties continue, replace the affected sensor as described later in this section.
4. If the calibration/response difculties continue after you replace the sensor, contact RKI Instruments, Inc., for further instruction.
Replacing Components of the GasWatch
This section describes procedures to replace the sensor, sensor dust cover, and batteries.
WARNING: Perform the procedures described in this section in a non-hazardous
environment.
Replacing the sensor
1. Verify that the GasWatch is off.
2. Loosen the two screws that secure the sensor retainer to the GasWatch, then remove the sensor retainer.
3. Unplug the sensor from its socket.
4. Plug the replacement sensor into the socket.
CAUTION: Verify that the sensor is properly aligned with the socket when plugging in the
sensor. “Forcing” the sensor in place may damage the sensor or socket.
5. Place the sensor retainer in its original position, then secure it to the GasWatch with the two screws you loosened in step 2.
6. Start-up the Gas Watch as described on page 4.
7. Calibrate the new sensor as described on page 9.
Replacing the sensor dust cover
1. Use a screwdriver or your ngernail to gently pry each side of the retaining strip away from the sensor dust cover.
2. Remove the sensor dust cover, then insert the replacement dust cover in its place.
3. Reattach the retaining strip in its original position. The GasWatch housing includes two recessed tabs on each side of the sensor dust
cover that allow the retaining strip to snap into place.
Replacing the batteries
1. Verify that the GasWatch is off.
2. Turn the GasWatch over to expose the battery compartment.
3. Loosen the captive screw that secures the battery compartment door, then remove the door.
4. The batteries may be attached to the opposite side of the door, or they may remain in their sockets.
5. Remove the batteries, then place the replacement batteries in the battery sockets. Position the batteries so the positive (+) side of the batteries are facing up.
6. Place the battery door in its original position, then secure it with the captive screw.
7. Start-up the Gas Watch as described on page 4, and verify that it is operating correctly.
12 • Maintenance GasWatch Instruction Manual (Two-Gas)
Accessories
Arm Strap
The GasWatch is supplied with a standard wrist strap. The arm strap is an optional accessory. You can use the arm strap to wear the GasWatch on your upper arm.
To install the arm strap:
NOTE: The wrist and arm straps are secured to the GasWatch by a bar. The bar is
1. Pull the wrist strap out of the strap loop at the bottom of the GasWatch.
2. Loosen the two screws that secure the oxygen sensor retainer, then remove the sensor
3. Slide the retaining bar out, then remove the wrist strap.
4. Place the arm strap in the same position as the wrist strap.
NOTE: Make sure you position the arm strap so you can use the velcro section properly
attached to the back of the GasWatch by two tabs.
retainer.
once the arm strap is installed.
5. Slide the retaining bar into its original position.
6. Place the oxygen sensor retainer in its original position, then secure it to the GasWatch with the two screws you loosened in step 2.
7. Insert the opposite end of the arm strap through the strap loop at the bottom of the GasWatch.
GasWatch Instruction Manual (Two-Gas) Accessories • 13
Parts List
Table 4: Parts List
Part Number Description
06-1248RK Calibration kit tubing (specify length in feet) 13-0101RK Wrist strap 13-0102RK Arm strap 21-1830RK Dust cover retainer 33-1004RK Sensor dust cover 49-1010RK Battery (1.4 V, zinc-air button type, Panasonic PR1662) 65-1058RK Oxygen sensor 65-2008RK Carbon monoxide sensor 65-2038RK Hydrogen sulde sensor 71-0031RK GasWatch Instruction Manual (two-gas version) 81-0065RK-01 Calibration cylinder (100 PPM CO in nitrogen; 34 liter) 81-0076RK-01 Zero air calibration cylinder (34 liter) 81-0078RK-01 Calibration cylinder (100% nitrogen; 34 liter) 81-0151RK-02 Calibration cylinder (25 PPM H2S in nitrogen; 58 liter)
81-1003RK Regulator (xed-ow, without gauge; 17/34 liter; 0.5 LPM 81-1004RK Regulator (xed-ow, with gauge; 58/103 liter; 0.5 LPM 81-CXGW-LV Calibration kit (CO/O2 version; 34 liter)
81-HXGW Calibration kit (H2S/O2 version; 58 liter)
14 • Parts List GasWatch Instruction Manual (Two-Gas)
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