PT2E-16214

Furnace Gas Detector HeadGD-A2400
Operating Manual(PT2E-162)(PT2-162)

Operating Precautions
This detector head is a gas detector that detects combustible gases in the air and triggers a gas alarm.
The gas detector is a safety unit, not an analyzer or densitometer which performs quantitative/qualitative
analysis/measurement for gases.
Please fully understand the following points before using it, so that it can be used properly.
1.

This detector head may be interfered by gases and vapors other than the gas to be detected.
Please note that the alarm may be triggered by interference. In addition, it may be fluctuated byenvironmental (temperature, humidity, etc.) changes in the installation site.

2.

The alarm must be set within a range where the performance of the detector head can be ensured.
In facilities compliant with the High Pressure Gas Safety Act, an alarm setting below our standard alarm
setpoint may trigger a false alarm.

3.

This is a safety unit, not a control unit.
The alarm contact output of the detector head must be used for an external alarm lamp/buzzer, while
the analog signal output must be used for an indicator or external recorder. If these outputs are used tocontrol other units, we shall not be responsible for any malfunctions.

4.

The gas sensing part of the gas detection sensor installed in this detector head is made of metal porous
sintered alloy permeated with an oxidation catalyst.
If silicon or sulfide compounds are accumulated on the surface of porous sintered alloy, the area of thegas sensing part becomes smaller, which may results in serious deterioration of its sensitivity.
For safety reasons, do not use the detector head under the presence of silicon or sulfide compounds
even though their amount is very small.

5.

For maintenance of the detector head, it must go through a regular maintenance, including
replacement and adjustment of the regular replacement parts as specified in the operating manual. In
addition, because this is a safety unit, it is recommended that a regular maintenance and a gas
calibration are performed every six months in accordance with the regulations.

GD-A2400

<Contents>

1
1-1.
1-2.
1-3.
1-4.

Outline of the Product .............................................................................................. 2
Preface .................................................................................................................... 2
Purpose of use ........................................................................................................ 2
Definition of DANGER, WARNING, CAUTION, and NOTE ..................................... 2
Method of confirmation for Standards and Explosion proof specification................. 23

2
2-1.
2-2.
2-3.
2-4.

Important Notices on Safety .................................................................................... 4
Danger cases .......................................................................................................... 4
Warning cases ......................................................................................................... 4
Precautions ............................................................................................................. 5
Safety Information ................................................................................................... 5

3

Product Components ............................................................................................... 7
Main unit and standard accessories ........................................................................ 7

4
4-1.
4-2.
4-3.
4-4.
4-5.

How to Use .............................................................................................................. 8
Before using the detector head ............................................................................... 8
Precautions for installation points ............................................................................ 8
Precautions for system designing ............................................................................ 9
How to install ........................................................................................................... 10
How to wire.............................................................................................................. 11

5
5-1.
5-2.
5-3.

How to Operate ....................................................................................................... 16
Preparation for start-up............................................................................................ 16
How to start the detector head ................................................................................ 16
How to exit............................................................................................................... 16

6
6-1.
6-2.
6-3.

Maintenance ............................................................................................................ 17
Maintenance intervals and items ............................................................................. 17
Gas calibration method............................................................................................ 18
Parts replacement ................................................................................................... 19

7
7-1.
7-2.
7-3.

Storage, Relocation and Disposal ........................................................................... 20
Procedures to store the detector head or leave it for a long time ............................ 20
Procedures to relocate the detector head or use it again ........................................ 20
Disposal of products ................................................................................................ 20

8

Troubleshooting ....................................................................................................... 21

9
9-1.
9-2.
9-3.

Product Specifications ............................................................................................. 23
List of specifications ................................................................................................ 23
List of accessories ................................................................................................... 24
Detection principle ................................................................................................... 24

10

Definition of Terms ................................................................................................... 25

GD-A2400-1-1 Outline of the Product1-1. Preface

1

Outline of the Product1-1. Preface
Thank you for choosing our furnace gas detector head GD-A2400. Please check that the model number ofthe product you purchased is included in the specifications on this manual.
This manual explains how to use the detector head and its specifications. It contains information required
for using the detector head properly. Not only the first-time users but also the users who have already used
the product must read and understand the operating manual to enhance the knowledge and experience
before using the detector head.
Product specifications may be abbreviated in this document as follows.
Japan Ex specification ： Japan specification
ATEX / IECEx specification ： Export specification

1-2. Purpose of use
 This detector head is a fixed type gas detector head which detects combustible gases in the furnace.
 This detector head is a safety unit, not a device aimed at performing quantitative/qualitative
analysis/measurement for gases. Please fully understand the features of the detector head before
using it, so that it can be used properly.
 The detector head detects combustible gases and outputs voltages according to gas concentrations.
 It must be used in combination with an indicator/alarm unit (optional). An indicator/alarm unit (optional)
displays concentrations and triggers an alarm when the alarm setpoint is exceeded.

1-3. Definition of DANGER, WARNING, CAUTION, andNOTE
DANGERWARNINGCAUTIONNOTE

GD-A2400

This message indicates that improper handling may cause serious
damage on life, health or assets.
This message indicates that improper handling may cause serious
damage on health or assets.
This message indicates that improper handling may cause minor
damage on health or assets.
This message indicates advice on handling.

-2-

1 Outline of the Product1-4. Method of confirmation for Standards and Explosion proof specification

1-4. Method of confirmation for Standards andExplosion proof specification
This instrument has some specification depends on standard and explosion proof certificate. Pleaseconfirm the detector specification before using. Please refer Declaration of Conformity that is at the end of
this manual if you have CE marking type.
You can confirm instrument specification to see name plate as follows.

Ex marking

Japan Ex certificate
CE marking

Japan Ex type name plate

ATEX/IECEx, CE
marking type name plate-3-

GD-A2400

2 Important Notices on Safety

2-1. Danger cases

2

Important Notices on
Safety2-1. Danger cases
DANGER<About explosion-proof> The window plate material is a polycarbonate resin. Do not use organic solvents and alkali types(liquid or vapor).
It may cause the color and shape of the window plate to be changed.
 Do not open the lid when applying current.
 Do not attempt to repair the detector.
 For the lid, use hexagon socket head bolts specified by RIKEN KEIKI.
 Do not apply a strong force or shock to the window plate. The explosion-proof performances may
be deteriorated due to damages. The explosion protection conditions for the detector is "low (2J)"
possibility of mechanical damage.
 Do not repair the explosion-proof joint surface.

2-2. Warning cases
WARNING
Need of grounding circuit
Do not cut the grounding circuit or disconnect the wire from the grounding terminal.
Defects in protective functions
Before starting the detector head, check the protective functions for defects. When seeming defects
are found in the protective functions, such as protective grounding, do not start the detector head.
Zero adjustment in the atmosphere
When the zero adjustment is performed in the atmosphere, check the atmosphere for freshness
before beginning the adjustment. If other gases exist, the adjustment cannot be performed properly,
thus leading to dangers when the gas leaks.
Response to a gas alarm
Issuance of a gas alarm indicates that there are extreme dangers. Take proper actions based onyour judgment.

-4-

GD-A2400

2 Important Notices on Safety

2-3. Precautions

2-3. Precautions
CAUTION
Do not use a transceiver near the detector head.
Radio wave from a transceiver near the detector head or its cables may disturb indication reading. If
a transceiver is used, it must be used in a place where it disturbs nothing.
Do not disassemble/modify the detector head.
Disassembling/Modifying the detector head will invalidate the warranty of the performance. Please
use the detector head properly in accordance with the operating manual.
Avoid applying organic solvents and others to the window plate for a long time.
The window plate material is a polycarbonate resin. Do not use organic solvents and alkali types(liquid or vapor). It may cause the color and shape of the window plate to be changed.
Do not forget to perform a regular maintenance.
Since this is a safety unit, a regular maintenance must be performed to ensure safety. Continuing to
use the detector head without performing a maintenance will deteriorate the sensitivity of the sensor,
thus resulting in inaccurate gas detection.

-5-

GD-A2400

2 Important Notices on Safety

2-4. Safety Information

2-4. Safety Information
Necessary information for explosion proof construction of Model GD-A2400.
<ATEX/IECEx Specifications>
The Model GD-A2400 is a fixed mount, detector head monitoring gas.
Technical Data
(Protection Method)

Flameproof enclosure “d”(Certificate Numbers)

IECEx DEK 11.0040X
DEKRA 11ATEX0095 X(Group)II(Category)

2G(Type of Protection and Marking code)

Ex db IIC T3(Equipment Protection Level)

Gb(Ambient Temperature)-20C to +60C(Process Temperature)-20C to +160C(Electrical Data)

Supply voltage: 2.3 V dc (Typ.)(Applicable Standard)

IEC 60079-0: 2017，IEC 60079-1: 2014
EN IEC 60079-0: 2018，EN 60079-1: 2014

(Manual Number)

PT2E-162

Installation

Installation Diagram
Hazardous Location(Zone 1)←→

Nonhazardous Location
Indicator

Gas Detector(GD‐A2400)＋－
SignalCVV Cable-6-＋－
SignalGD-A2400

3 Product Components

Main unit and standard accessories

3

Product Components
Main unit and standard accessories
Main Unit (including a cable gland)Standard AccessoriesOperating manual
Dedicated handling lever (used for the wiring)
Flange gasket
Exhaust air direction nameplate-7-

GD-A2400

4 How to Use

4-1. Before using the detector head4

How to Use
4-1. Before using the detector headNot only the first-time users but also the users who have already used the product must follow the operating
precautions.
Ignoring the precautions may damage the detector head, resulting in inaccurate gas detection.

4-2. Precautions for installation points
CAUTION
This is a precision device. Because the detector head may not provide the specified performance insome places (environments), check the environment in the installation point, and then take appropriate
actions if necessary.
Because the detector head plays an important role for safety and disaster prevention, as many units ofthe detector head as needed must be installed in appropriate points.
Because points where gases leak and remain easily are different depending on the types of gases andthe working areas, please decide carefully on installation points and the number of units to be installed.
Do not install the detector head in a place with vibrations or shocks.
The detector head must be installed in a stable place without vibrations or shocks and it cannot drop.
Do not install the detector head in a place exposed to water, oil or chemicals.
When selecting installation points, avoid a place where the detector head is exposed to water, oil orchemicals.
Install the detector head in a place with operating environment temperatures that meet the following
requirements:<Export Specification>
Main unit case part:The detector head must be installed in a stable place where the operating temperature is 0 to +50C and
do not change suddenly.
Gas sensor part: 0 to +160C<Japan Specification>
Main unit case part:The detector head must be installed in a stable place where the operating temperature is -20 to +60Cand do not change suddenly.
Gas sensor part: 0 to +160C-8-

GD-A2400

4 How to Use

4-3. Precautions for system designing

Do not install the detector head in a place exposed to direct sunlight or sudden changes in the temperature.
When selecting installation points, avoid a place where it is exposed to direct sunlight or radiant heat
(infrared rays emitted from a high-temperature object), and where the temperature changes suddenly.
Condensation may be formed inside the detector head, or the detector head cannot adjust to suddenchanges in the temperature.
Keep the detector head (and its cables) away from noise source devices.
When selecting installation points, avoid a place where high-frequency/high-voltage devices exist.
Do not install the detector head in a place where maintenance of the detector head cannot be performed orwhere handling the detector head involves dangers.
Regular maintenance of the detector head must be performed.
Do not install the detector head in a place where the machinery must be stopped when maintenance isperformed in its inside, where parts of the machinery must be removed to perform maintenance, or where
the detector head cannot be removed because tubes or racks prevent access to it. Do not install thedetector head in a place where maintenance involves dangers, for example, near a high-voltage cable.
Do not install the detector head in machinery which is not properly grounded.
Before installing the detector head in machinery, the machinery must be grounded properly.
Do not install the detector head in a place where other gases exist around it.
The detector head must not be installed in a place where other gases exist around it.

4-3. Precautions for system designing
CAUTION
An unstable power supply and noise may cause malfunctions or false alarms.
The descriptions in this section must be reflected on the designing of a system using the detector head.
Introducing protective measures against lightning
If cables are installed outside the factory/plant, or if internal cables are installed in the same duct as the cables
coming from outside the factory/plant, "lightning" will cause problems. Because lightning acts as a large emission
source while cables act as a receiving antenna, devices connected to the cables may be damaged.
Lightning cannot be prevented. Cables installed in a metal conduit or under the ground cannot becompletely protected from inductive lightning surge caused by lightning. Although complete elimination ofdisasters caused by lightning is impossible, the following protective measures can be taken.

Protection against
lightning

Grounding

Take appropriate measures in accordance with the importance of the facilities
and the environment.
 Provide protection by a lightning arrester (cable arrester).
(Although inductive lightning surge can be transmitted through the cable, it isprevented by installing a lightning arrester before the field devices and central
processing equipment. For information on how to use a lightning arrester,
please contact the manufacturer.)
In addition to lightning, there are more sources of surge noise. To protect units
from these noise sources, the units must be grounded.

* The lightning arrester has a circuit to remove a surge voltage which damages field devices, so that signals
may be attenuated. Before installing a lightning arrester, verify that it works properly.

-9-

GD-A2400

4 How to Use

4-4. How to install

4-4. How to install<Maintenance Space><How to fix the windscreen>

NOTE

Exhaust air

When performing maintenance,
installation/de-installation is required in
the direction shown below.
Do not cover installation flange by heatinsulator etc.

Installation flange

Exhaust air
direction nameplate

Windscreen

Bolt for fixing
the windscreen

Lid
Installation/de-installation direction

WARNING

Furnace wall

When the detector head is to be installed in a furnace,make sure that the exhaust air hits the windscreen where it
is installed.
Securely fix the windscreen with bolts for fixing it.
After the gas detector head is installed, affix the supplied"exhaust air direction nameplate" on the surface of the lid.

Space required to attach/detach a gas detector head
Recommendation 1000

<How to Install>
Main unit case
Windscreen

Lid

Housing(For M12)

A-A cross-section (Flange installation hole)
Reference line 2

Reference line 1

Ambient temperature to
the left of Reference Line
2 in the furnace (gassensor part):0-160℃(Length of part inserted into the furnace)

Ambient temperature to theright of Reference Line 1
outside of the furnace (mainunit case part):0-50℃

Welded all roundGas sensor part

GasketExternal cable inlet part for
power supply and signals

WARNING
Install at the place of
furnace wall where
sealing can be doneby gasket etc.

Installation flange
Furnace wall

Over 150

CAUTION

NOTE

When performing maintenance,
de-installation is required in the direction
shown above.
In case of installing conduit, use the flexible
conduit.

For higher accuracy measurement, set the gas sensor
part to the place where is over 150mm inside frominternal wall of furnace.

- 10 -

GD-A2400

4 How to Use

4-5. How to wire

4-5. How to wire
CAUTION Be careful not to damage the internal components when wiring. In addition, be careful not to apply
stresses on the detector head when (overweight) cables are installed.
 The connecting cables must not be installed together with the motor power cables, etc. When thecables must be installed together for unavoidable reasons, put the connecting cables in a metal
conduit. The conduit must be connected to a grounding circuit.
 When stranded wires are used, prevent wires from contacting each other.
 Use the dedicated handling lever to wire.

<Recommended Cable>
CVV1.25 mm2 - 4-core<Parts. length table of outside conductor lead-in>
The parts for the external cable inlet are different from specifications. Use the appropriate parts, referringto the following lists.
Export Specification
Cable overall outer
diameter(mm)Rubber seal innerdiameter(mm)Washer innerdiameter(mm)Clamp innerdiameter(mm)From Φ9.6 to less than Φ10.5

Φ11

Φ12

Φ10.8

From Φ10.5 to less than Φ11.5

Φ12

Φ12

Φ11.8

From Φ11.5 to less than Φ12.5

Φ13

Φ14

Φ12.8

From Φ12.5 to less than Φ13.0

Φ13.5

Φ14

Φ13.8

Rubber seal innerdiameter(mm)Washer innerdiameter(mm)From Φ9.6 to less than Φ11.0

Φ11

Φ12

From Φ11.0 to less than Φ11.5

Φ12

Φ12

From Φ11.5 to less than Φ12.0

Φ12

Φ14

From Φ12.0 to less than Φ13.0

Φ13

Φ14

Φ13.0

Φ13.5

Φ14

Japan Specification
Cable overall outer
diameter(mm)φ23- 11 -

GD-A2400

4 How to Use

4-5. How to wire

<Figure of Terminal Plate>3
To the indicator/
alarm unit
(optional)

4
5
6

Groundingterminal<Specifications of Terminal Plate>Specifications of terminal plate Rated voltage: 250 VAC
 Rated current: 12 A
However, it depends on cables to be used.
Connection conditions
 Cables: 0.08 - 2.5 mm2
 Bare wire length: 8 - 9 mm
 Connecting tool: Dedicated handling lever (accessory)

CAUTION
The specified bare wire length must be observed when the wire insulation is peeled off.
Improper clamping of the wire due to a shorter bare wire length may cause defective electric
conduction or heating.
Catching the wire insulation due to a shorter bare wire length may cause defective electric
conduction or heating.
Exposing the wire due to a longer bare wire length may cause defective insulation or a short circuit.
Be careful not to break up the wire.If the wire is broken up when inserted to the terminal, this may
cause defective insulation or heating.

8 - 9 mm

Compatible bar terminal
For a bar terminal, the following items are available.
 Bar terminal (ferrule): Model 216 Series (manufactured by WAGO)
 Crimping tool: Model VarioCrimp 4 (206-204) (manufactured by WAGO)- 12 -

GD-A2400

4 How to Use

4-5. How to wire

CAUTION
A bar terminal of the specified model must be used. Using other bar terminals invalidates thewarranty of the performance.

<How to Connect to Terminal Plate>
When cables are connected to the connectors, use the dedicated lever or a flathead screwdriver to do it asshown below.

CAUTION
The right tools must be used.
In principal, one wire can be connected to one wiring hole.
When the wire is inserted into the driver slot by mistake, it does not contact the conductive part. Thismay cause defective electric conduction or heating.
When the wire is inserted under the spring by mistake, it does not contact the conductive part. Thismay cause defective electric conduction or heating.

NOTE<How to Use the Dedicated Handling Lever>Push the lever with your finger
to lower the spring in its inside.

While holding down the lever, insert the wire
into the (round) wiring hole until it reaches thedeepest point.

To check whether the wire is connected securely, pull the wire gently. (Do not pull the wire strongly.)- 13 -

GD-A2400

4 How to Use

4-5. How to wire

<Attaching External Cable>
The way to attach the external cable is different from specifications. Attach the external cable appropriately,referring to the following information.
Export Specification
Attach the parts in the following order: cable grand, eccentric washer, washer, and rubber seal to thecable, then connect the cable into the main unit and screw the cable gland to tighten the rubber seal.
Japan Specification
Attach the parts in the following order: cable grand, washer, and rubber seal to the cable, then connect
the cable into the main unit and screw the cable gland to tighten the rubber seal.

Below 1.5mm（Japan Specification）

CAUTION

 Export Specification:
Ensure the tightening torque for the cable gland and seal plug to be 40 N･m or larger.
 Japan Specification:
Tighten a cable gland with a tool until a clearance between the cable gland and a main unit caseis below 1.5 mm.
 If it is difficult to tighten the cable gland, grease its screw part and then tighten it with the tool.

- 14 -

GD-A2400

4 How to Use

4-5. How to wire

<Grounding>Connect the detector head to your grounding terminal with the external terminal.

WARNING Before turning on the detector head, do not forget to connect it to a grounding terminal.
 For stable operation of the detector head and safety, it must be connected to a grounding
terminal. Do not connect the grounding wire to a gas pipe.
 The grounding must be made as D type grounding (below 100 Ω of grounding resistance).

<Wiring Example>
Connecting to the indicator/alarm unit (optional)
GD-A2400
From the top in the front view
Terminal 3
Terminal 4
Terminal 5
Terminal 6

GP-571A/581
GP-591, etc.

3

3

4

4

5

5

6

6
CVV1.25 mm2 - 4-coreE- 15 -

GD-A2400

5 How to Operate

5-1. Preparation for start-up

5

How to Operate
5-1. Preparation for start-up
Before supplying power, read and understand the following precautions. Ignoring these precautions may
cause an electric shock or damage the detector head.
 Check that the detector head is installed properly.
 Connect the detector head to a grounding circuit.
 Check that the wiring is connected to external device properly.

NOTE
Read also the operating manual of the indicator/alarm unit (optional).

5-2. How to start the detector head
 Since the detector head has no power switch, turn on the power of the indicator/alarm unit (optional) toturn it on.
 After the indicator/alarm unit (optional) completes the initial clear operation, it enters the detection
mode swiftly.

CAUTION
After the warm-up is completed, perform a gas calibration.

5-3. How to exit
To turn off the detector head, turn off the power of the indicator/alarm unit (optional).

WARNING When the detector head is turned off, an alarm may be activated on the upper (central) system.
Before turning off the detector head, perform proper processing on the upper (central) system.
 Decide whether the power can be turned off by checking the operations of the devices connectedto the indicator/alarm unit (optional).

- 16 -

GD-A2400

6 Maintenance

6-1. Maintenance intervals and items

6

MaintenanceThis is an important instrument for the purpose of safety.
To maintain the performance of the detector head and improve the reliability of safety, perform a regular
maintenance.

NOTE
Perform a regular maintenance on the detector head together with the indicator/alarm unit (optional).

6-1. Maintenance intervals and items
 Daily maintenance:
Perform maintenance before beginning to work.
 Monthly maintenance: Perform maintenance on the alarm circuit (alarm test) once a month.
 Regular maintenance: Perform maintenance once or more for every six months to maintain theperformance as a safety unit.
Maintenance
itemPower Supply
Check
Concentration
Display Check

Alarm Test
Span
Adjustment
Gas Alarm
Check

Maintenance content
Check that the power lamp lights up.
Check that the concentration display
value is zero. When the reading isincorrect, perform the zeroadjustment after ensuring that noother gases exist around it.
Check the alarm circuit by using thealarm test function.
Perform the sensitivity calibration byusing the calibration gas.
Check the gas alarm by using thecalibration gas.

Daily
maintenance

Monthly
maintenanceRegularmaintenance































<About Maintenance Services> We provide services on regular maintenance including span adjustment, other adjustments andmaintenance.
To make the calibration gas, dedicated tools, such as a gas cylinder of the specified concentration andgas sampling bag must be used.
Our qualified service engineers have expertise and knowledge on the dedicated tools used for services,along with other products. To maintain the safety operation of the detector head, please use ourmaintenance service.
 The followings are typical maintenance services. For more information, please contact RIKEN KEIKI.

- 17 -

GD-A2400

6 Maintenance

6-2. Gas calibration method

Main Services
Power Supply
Check

:

Concentration
Display Check
Alarm Test

:
:

Span
Adjustment
Gas Alarm
Check:Cleaning andRepair of theGas Monitor(visualdiagnosis)
Replacement ofConsumable
Parts

:

:

:

Checks the power supply voltage.
Verifies that the power lamp lights up.
(Verifies that relevant points can be identified on the system.)(When a UPS (uninterruptible power system) is used, checks the operation with the UPS.)
Verifies that the concentration display value is zero by using the zero gas.
Performs the zero adjustment if the reading is incorrect.
Inspects the alarm circuit by using the alarm test function.
• Checks the alarm lamps. (Checks each activation of ALM1 and ALM2.)• Checks the external alarm. (Checks the activation of the external alarm, such as a buzzer.)
Performs the sensitivity calibration by using the calibration gas.
Checks the gas alarm by using the calibration gas.
• Checks the alarm. (Checks the alarm activation when the alarm setpoint is reached.)• Checks the delay time. (Checks time to delay until the alarm is triggered.)• Checks the alarm lamps. (Checks each activation of ALM1 and ALM2.)• Checks the external alarm. (Checks the activation of external alarms, such as a buzzer andreset signal.)
Checks dust or damage on surface, cover, or internal parts of the detector head, clean andrepair such parts of the detector head.
Replaces parts which are cracked or damaged.

Replaces consumable parts, such as a sensor.

<Cleaning of Detector>
Clean the detector head if it becomes extremely dirty. The detector head must be turned off while cleaning it.
Use a waste cloth to remove dust. Do not use water or organic solvent for cleaning because they may cause
malfunctions.

6-2. Gas calibration method
Perform a gas calibration using the calibration gas.
 Zero adjustment gas
 Span adjustment gas (collected in a gas sampling bag) Gas sampling bags

GD-A2400 gas detector headGassampling
bag
for exhaust

OUT

IN

Gas calibration adapter

Needle valve

Flow meterGas
samplingbag

Pump
1.0 ± 0.2 L/min

Perform the zero adjustment and the span adjustment on the indicator/alarm unit (optional).

- 18 -

GD-A2400

6 Maintenance

6-3. Parts replacement

CAUTION
Before starting the span adjustment, provide the detector head with the span adjustment gas andwait until the indicator is stabilized.

NOTE
Read also the operating manual of the indicator/alarm unit (optional).

6-3. Parts replacement<Sensor Replacement>
Our service engineers need to replace the sensor and perform the gas calibration.
Please contact RIKEN KEIKI.

NOTE
The gas calibration using the standard gas is required after the sensor is replaced. Please request it to
RIKEN KEIKI.

<Replacement of Regular Replacement Parts>
List of recommended regular replacement parts
No.
1
2

Item
O-ring(for the housing joint surface)
Rubber seal(for flange installation)

Maintenanceintervals

Replacement
intervals (year)

Quantity(pieces/unit)

1 year3 - 6 years

1

1 year3 - 6 years

1

NOTE

 The above replacement intervals are recommendation only. The intervals may change depending on
the operating conditions. These intervals do not mean the warranty periods either. The result of theregular maintenance may determine when to replace the parts.

- 19 -

GD-A2400

7 Storage, Relocation and Disposal

7-1. Procedures to store the detector head or leave it for a long time7

Storage, Relocation and
Disposal
7-1. Procedures to store the detector head or leave it
for a long time
The detector head must be stored under the following environmental conditions.
 In a dark place under the normal temperature and humidity away from direct sunlight In a place where gases, solvents or vapors are not present

7-2. Procedures to relocate the detector head or use it
again
When the detector head is relocated, select a new place in accordance with "4-2. Precautions for installation
points" and "4-4. How to install".
For information on wiring, see "4-5. How to wire". The unpowered time must be minimized when thedetector head is relocated.

CAUTION
When using a relocated or stopped/stored detector head again, do not forget to perform a gas
calibration. For information on readjustment including a gas calibration, please contact RIKEN
KEIKI.

7-3. Disposal of products
When the detector head is disposed of, it must be treated properly as an industrial waste in accordance withthe local regulations.

- 20 -

GD-A2400

8 Troubleshooting

8 Troubleshooting

8

Troubleshooting
The Troubleshooting does not explain the causes of all the malfunctions which occur on the detector head.
This simply helps to find the causes of malfunctions which frequently occur. If the detector head shows asymptom which is not explained in this manual, or still has malfunctions even though remedial actions aretaken, please contact RIKEN KEIKI.

NOTE
Read also the operating manual of the indicator/alarm unit (optional).

<Abnormalities on the Detector Head>
Symptom/Display
The power of theindicator/alarm unit
(optional) cannot
be turned ON.
Abnormaloperations of theindicator/alarm unit
(optional)
Fault alarm
activation of theindicator/alarm unit
(optional)

GD-A2400

CausesActions

The wiring is not correct.

Connect the wiring properly.

Cable abnormalities (opencircuit/not connected/shortcircuit)Check the wiring of detector head and related
devices around it.

Disturbances by sudden
surge noise, etc.

Turn off and restart the detector head.
If such a symptom is observed frequently, takeappropriate measures to eliminate the noise.

The cable is not connectedor improperly connected.

Check if the cable is securely fastened to theterminal plate.

Faults of the sensor

Replace the sensor with a new one.

- 21 -

8 Troubleshooting

8 Troubleshooting<Abnormalities of Indicator/Alarm Unit Readings>
Symptoms
The reading rises(drops) and it remainsso.

CausesDrifting of sensor
outputEnvironmental
changes
Disturbance bynoise

A gas alarm is triggered
despite of no gas leakand no otherabnormalities at thedetection point.

Slow response

Sudden change inthe environment

Deteriorated sensor
sensitivity

Actions
Perform the zero adjustment.
When the sensor ambient temperature rises (or drops),the "zero point" drops (or rises), but this is not a
malfunction. Perform the zero adjustment at theoperating temperature.
Turn off and restart the detector head.
If such a symptom is observed frequently,
take appropriate measures to eliminate the noise.
When the environment (temperature, etc.) changes
suddenly, the detector head cannot adjust to it and isaffected by it.
In some cases, the detector head triggers an indication
alarm.
Because the detector head cannot be used undersudden and frequent environmental changes, the user
should take some preventive actions to eliminate them.
Replace the sensor with a new one.

- 22 -

GD-A2400

9 Product Specifications

9-1. List of specifications

9

Product Specifications
9-1. List of specifications<ATEX/IECEx Specification>
Detection principle
Gas to be detected
Detection method
Transmission system
Transmission cable
Cable connecting
portOperatingtemperatures
Structure
Explosion-proof
structure
Explosion-proof class
External dimensions
WeightOuter color

Catalytic combustion typeCombustible gas
Direct insertion type
Sensor direct output
CVV, etc. (1.25mm2) - 4-core
Pressure proof packing gland (Compatible cables Φ9.6 to Φ10.5 mm in outer
diameter)
Sensor part: 0～+160C (at a constant condition)
Main unit case part: -20～+60C (at a constant condition)
Direct insertion type
Flame-proof enclosures
Ⅱ 2 G Ex db ⅡC T3 Gb(ATEX) / Ex db ⅡC T3 Gb(IECEx)
Approx. 148 (W) x 167 (H) x 458 (D) mm (projection portions excluded)
Approx. 4.6 kg
Munsell 7.5BG5/2<Japan Ex Specification>
Detection principle
Gas to be detected
Detection method
Transmission system
Transmission cable
Cable connecting
portOperatingtemperatures
Structure
Explosion-proof
structure
Explosion-proof class
External dimensions
WeightOuter color

GD-A2400

Catalytic combustion typeCombustible gas
Direct insertion type
Sensor direct output
CVV, etc. (1.25mm2) - 4-core
Pressure proof packing gland (Compatible cables Φ9.6 to Φ10.5 mm in outer
diameter)
Sensor part: 0～+160C (at a constant condition)
Main unit case part: 0～+50C (at a constant condition)
Direct insertion type
Flame-proof enclosures
Ex d IIC T3
Approx. 148 (W) x 167 (H) x 458 (D) mm (projection portions excluded)
Approx. 4.6 kg
Munsell 7.5BG5/2* Specifications subject to changes without notice.
- 23 -

9 Product Specifications

9-2. List of accessories

9-2. List of accessoriesOperating manual ････････････････････････････ 1sheet
Dedicated handling lever ･････････････････････ 1pce.
Flange gasket ･･･････････････････････････････ 1pce.
Exhaust air direction nameplate ･･････････････ 1pce.

9-3. Detection principle
When a combustible gas burns on the surface of a highly active oxidation catalyst in catalytic combustion,
the contact burning-type sensor measures resultant temperature changes by measuring the resistancechanges in the heat-resistant alloy wire coil.
The sensor consists of two elements: A detecting element having a heat-resistant alloy wire coil with anultrafine particle oxidation catalyst sintered on it together with a carrier and a temperature-compensating
element with a mixture of gas-inert alumina and glass sintered on it.
When a combustible gas comes into contact with the surface of the detecting element with oxidation
catalyst sintered on it, the gas burns, causing the temperature to rise. In accordance with this temperaturechange, there occurs a change in the resistance of a heat-resistant alloy wire coil that constitutes theelement. These resistance values are approximately proportional to gas concentrations. From the changes
in the resistance values, potential differences are obtained using a bridge circuit and displayed as gas
concentrations on the meter.
[Structure][Principle]
A

Alumina
Oxidation catalyst

Heat-resistant alloy wire coil

C: Compensating
element

D: Detecting element

1.4 - 1.6 mm

X

Fixed
resistanceFixedresistance

Y

M

B

1.3 - 1.8 mm

Variable resistor for bridge
equilibrium adjustment
E
SW
VR

SwitchPower supply
Variable resistor for bridge
voltage adjustment- 24 -

GD-A2400

10 Definition of Terms

10 Definition of Terms

10

Definition of Terms
Catalytic
combustion type
Initial clear
Full scale%LEL
Calibration

GD-A2400

This is a principle of the sensor installed in the detector head.
See "9-3. Detection principle" for details.
Output from the detector head fluctuates for a while after turning on the power.
This is a function to prevent triggering alarm during that time.
Maximum value of the detection range.
A unit which the lower explosive limit (LEL) of the combustible gas to be detected is
set to 100.
Adjusts the readings to the calibration gas concentration value by using thecalibration gas.

- 25 -