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 • [phone]

.

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 flashes.

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 flashes.

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 flashes.

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 flashes.

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

flashes, 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 GasWatch’s 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 flashes

• gas reading flashes

• back light turns on

2

• alarm light flashes

• 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 flashes

Battery Failure • gas reading replaced by

double pulsing tone

FAIL

• battery icon flashes

Sensor Failure

1

The oxygen sensor does not initiate STEL or TWA alarms.

2

If the oxygen sensor fails, the gas reading flashes 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 fixed-flow 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 fixed-flow 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 fixed-flow 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 difficulties continue, replace the affected sensor as
described later in this section.

4. If the calibration/response difficulties 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 fingernail 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 sulfide 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 (fixed-flow, without gauge; 17/34 liter; 0.5 LPM
81-1004RK Regulator (fixed-flow, 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)