PT2E-1929

Fixed Combustible/
Toxic Gas Detector HeadGD-A80D-AS Series
GD-A80D-AS
GD-A80DV-AS
GD-A80DS-AS
GD-A80DN-AS
Operating Manual

Operating Precautions
This detector is a gas detector that detects combustible gases or toxic 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 may be interfered by gases other than the gas to be detected and vapors.
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 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.
4. If silicon or sulfide compounds are accumulated on the surface of sintered alloy of the gas detector
sensor used for this unit, the area of the gas sensing part becomes smaller, which may result in serious
deterioration of its sensitivity.
For safety reasons, do not use the detector under the presence of silicon or sulfide compounds eventhough their amount is very small.
5. For maintenance of the detector, it must go through a regular maintenance, including replacement andadjustment 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 calibration are performed every
six months in accordance with the regulations.

-2-Contents
1. Outline of the Product .......................................................................................................................................... 4
1-1. Preface ..........................................................................................................................................................4
1-2. Purpose of use ..............................................................................................................................................4
1-3. Definition of DANGER, WARNING, CAUTION and NOTE ...........................................................................4
1-4. Method of confirmation for standards and explosion proof specification ......................................................5
2. Important Notices on Safety ................................................................................................................................ 6
2-1. Danger cases ................................................................................................................................................6
2-2. Warning cases...............................................................................................................................................6
2-3. Precautions ...................................................................................................................................................7
2-4. Safety information .........................................................................................................................................8
3. Product Components ......................................................................................................................................... 11
3-1. Main unit and standard accessories ........................................................................................................... 11
3-2. Names and functions for each part .............................................................................................................123-3. Block diagram .............................................................................................................................................13
4. How to Use ........................................................................................................................................................ 14
4-1. Before using the detector ............................................................................................................................14
4-2. Precautions for installation sites .................................................................................................................14
4-3. Precautions for system designing ...............................................................................................................15
4-4. How to install ...............................................................................................................................................16
4-5. Installation procedure ..................................................................................................................................17
4-6. How to wire .................................................................................................................................................18
4-7. How to Tube ................................................................................................................................................22
5. How to Operate.................................................................................................................................................. 23
5-1. Preparation for start-up ...............................................................................................................................23
5-2. How to activate the detector .......................................................................................................................23
5-3. Flow Rate Adjustment .................................................................................................................................23
5-4. How to detect ..............................................................................................................................................24
5-5. How to exit ..................................................................................................................................................24
6. Maintenance ...................................................................................................................................................... 25
6-1. Maintenance intervals and items ................................................................................................................25
6-2. Calibration method ......................................................................................................................................27
6-3. Replacement parts ......................................................................................................................................29
7. Storage, Relocation and Disposal ..................................................................................................................... 31
7-1. Procedures to store the detector or leave it for a long time ........................................................................31
7-2. Procedures to relocate the detector or use it again ....................................................................................31
7-3. Disposal of products ...................................................................................................................................31
8. Troubleshooting ................................................................................................................................................. 32
9. Product Specifications ....................................................................................................................................... 33
9-1. Standard specifications ...............................................................................................................................33
9-2. Detection principle.......................................................................................................................................35
10. Definition of Terms ........................................................................................................................................... 38-3-

1. Outline of the Product1-1. Preface

1

Outline of the Product1-1. Preface
Thank you for choosing our fixed combustible/toxic gas detector head GD-A80D-AS Series. Please check thatthe model number of the product you purchased is included in the specifications on this manual.
This manual explains how to use the detector and its specifications. It contains information required for using
the gas detector properly. Not only the first-time users but also the users who have already used the productmust read and understand the operating manual to enhance the knowledge and experience before using thedetector.
Note that the detector cannot be used alone. Use it with the dedicated indicator/alarm unit. Be sure to readthe operating manual of the indicator/alarm unit as well.

1-2. Purpose of use･ This detector is a fixed type gas detector head which detects leak of combustible or toxic gases.
･ The detector is a safety unit, not an analyzer or densitometer which performs quantitative/qualitative
analysis/measurement for gases.
Please fully understand the features of the detector before using it, so that it can be used properly.
･ The detector detects abnormalities caused by presence of gases (leak) with the built-in gas sensor.
･ The detector draws a gas by an aspirator using compressed air to perform gas detection.
･ Use the detector in combination with an indicator/alarm unit that indicates a gas concentration and triggers
an alarm.
･ When the detector detects a leak of combustible or toxic gas, it outputs a voltage according to the gas
concentration. The indicator/alarm unit indicates the gas concentration and triggers an alarm if a preset
concentration level is exceeded.

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

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

WARNING

This message indicates that improper handling may cause serious damage on
health or assets.

CAUTION

This message indicates that improper handling may cause minor damage on
health or assets.

NOTE

This message indicates advice on handling.

-4-2. Important Notices on Safety

2-4. Safety information

2-4. Safety information
Observe the followings to maintain an explosion-proof system.
Outline of the unit
･ This unit is a compressed air-driven aspirator suction type gas detector head (GD-A80D-AS Series) used inconnection with the indication alarm to detect target gas.
･ This unit is designed to have a gas detector head (GD-A80D Series) incorporated in the sampling device.
<ATEX/IECEx/UKEX Specifications>Technical Data
(Explosion-proof enclosures)(Group)(Category)(Explosion-proof class)(Protection level)(Ambient temperature)*(Rating)･ Detecting element(Certificate numbers)(Applicable Standard)

Flame-proof enclosures "d"II
2G
Ex db IIC T4
Gb-40ºC to +53ºC
GD-A80(D)DC3. 0V 430mA or DC5. 0V 200mA
GD-A80(D)V
DC6. 5V 205mA or DC3. 5V 350mA
GD-A80(D)S
DC3. 0V 500mA or DC5. 0V 200mA
GD-A80(D)N
DC3. 3V 170mA or DC1. 0V 220mA
IECEx DNV 21.0052X
DNV 21 ATEX 64381X
DNV 22 UKEX 25925X
EN IEC 60079-0：2018, EN 60079-1：2014
IEC60079-0 (2017), IEC60079-1 (2014-06)
BS EN IEC60079-0:2018, BS EN 60079-1:2014*The ambient temperature range which maintains a capability of explosion proof of the label on the detector
head is -40 to +53℃. However, the operating temperature range to maintain gas detection performance is 20 to +53℃.
Specific conditions of “X”-mark:Regarding ATEX specification, the measuring function according to Annex II paragraph 1.5.5 of the Directive is notcovered by this EU-type examination.
It shall comply with the requirements from the relevant European harmonized standards which provide guidance on theperformance of gas detection equipment and safety devices.
“The measuring function according to schedule 1, paragraph 24 of the Regulation is not covered in this UK-type
examination. It shall comply with the requirements from the relevant UK Designated Standards which provide guidanceon the performance of gas detection equipment.”
The flameproof joints not intended to be repaired.
Fasteners used for enclosure are from stainless steel property class A2-70.
Cable gland may not provide sufficient clamping. User shall provide additional clamping against the cable
pulling and twisting.

-8-4. How to Use

4-6. How to wire
Rubber seal

NOTE The following table shows an example of overall outer diameters of cables. Use them for reference.
The overall outer diameters must be checked because they somewhat vary between manufacturers.
Numberof core2
3456CVV 1. 25 mm2

CVV 2 mm2

CVVS 1. 25 mm2

CVVS 2 mm2

Φ9. 2
Φ9. 7
Φ10. 5
Φ11. 5
Φ12. 5

Φ10. 5
Φ11. 0Φ11. 5
Φ12. 5
Φ13. 5

Φ9. 6
Φ10. 5
Φ11. 0Φ12. 0Φ13. 0Φ10. 5
Φ11. 0Φ12. 0Φ13. 0Φ14. 0- 19 -

6. Maintenance

6-1. Maintenance intervals and items<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 and gas
sampling bag must be used.
Our service engineers have expertise and knowledge on the dedicated tools used for services, along withother products. To maintain the safety operation of the unit, please use our maintenance service.
• Typical maintenance services are listed as follows. For more information, please contact RIKEN KEIKI.
Main services
Power supply
check*
Status check*
Concentration
display check*
Flow rate check::

Checks the power supply voltage.
Verifies that the power lamp lights up.
Verifies that the fault lamp does not light up.
Verifies that the concentration display value is zero by using the zero gas.
Performs zero adjustment if the reading is incorrect.
Checks the flow rate for abnormalities by using an external flow meter.
If the flow rate is incorrect, performs the flow rate adjustment.
Checks the dust filter for dust or clogging.
Replaces a dirty or clogged dust filter.
Inspects the alarm circuit by using the alarm test function.
• Checks the alarm lamp. (Checks ALM activation.)• Checks the external alarm. (Checks the activation of the external alarm, such as abuzzer.)Performs the span adjustment by using the calibration gas.
Checks the gas alarm by using the calibration gas.
• Checks the alarm. (Checks triggering of alarm when the alarm setpoint is reached.)• Checks the delay time. (Checks time to delay until the alarm is triggered.)• Checks the alarm lamp. (Checks ALM activation.)• Checks the external alarm. (Checks the activation of external alarms, such as abuzzer and reset signal.)
Checks dust or damage on the surface, cover or internal parts of the unit, and cleansor repairs such parts as needed.
Replaces parts which are cracked or damaged.
Uses the keys to check the operation of functions and parameters.

::

Filter check:

Alarm test*:

Span adjustment*
Gas alarm check*::

Cleaning and repairof the unit
(visual diagnosis)
Unit operation
check*
Replacement ofconsumable parts::

Replaces consumable parts, such as a sensor, filter and pump.

:* Check and adjustment are performed at the indicator/alarm unit side.

- 26 -

6. Maintenance

6-3. Replacement parts<Replacement of Regular Replacement Parts>
List of recommended regular replacement parts
No.

Item

Maintenanceintervals

Replacement
intervals(year)

Quantity(pieces/unit)

Remarks

1

Rubber seal (sensor)

6 months

3 - 8 years

1Part number: 4262 4545 102

Aspirator cap

6 months

3 - 8 years

1

PP/Bs/SUS types* The operation must be checked after replacement by our service engineer. For the stable operation of theunit and safety, ask RIKEN KEIKI to take care of replacement of the part. Request RIKEN KEIKI for
operation check.

NOTE

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

- 30 -

8. Troubleshooting

8

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

<Abnormalities of Readings>* Take remedial actions to indicator/alarm unit as well. See the operating manual of the indicator/alarm unit
for details.
Symptoms

The reading rises(drops) and it remainsso.

CausesDrifting of sensor
outputPresence ofinterference gas

Slow leakA gas alarm istriggered despite ofno gas leak and noother abnormalities atthe detection point.

Slow response

Span adjustment
impossible

Actions
Perform zero adjustment.
Disturbances by interference gases, such as solvents,
cannot be eliminated completely. For information on
actions, such as removal filter, please contact RIKEN
KEIKI.
A very small amount of the gas to be detected may beleaking (slow leak). Because ignoring it may cause
dangers, take a remedial measure, i.e., taking actions thesame as those for the gas alarm.

Environmental
changes

Perform zero adjustment.

Presence ofinterference gas

Disturbances by interference gases, such as solvents,
cannot be eliminated completely. For information on
actions, such as removal filter, please contact RIKEN
KEIKI.

Disturbance by noise

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

Sudden change inthe environment

When the environment (temperature, etc.) changes
suddenly, the detector cannot adjust to it and is affected by
it. In some cases, the detector triggers an indication alarm.
Because the detector cannot be used under sudden andfrequent environmental changes, any preventive actions toeliminate them should be taken by the user.

Deteriorated sensor
sensitivity
Cloggeddust filter
Bent, clogged orleakedsuction/exhaust tube
Condensation isformed inside thesuction tube.
Improper calibration
gas concentration
Deteriorated sensor
sensitivity

Replace the sensor with a new one.
Replace the dust filter.
Fix the defective parts.
Fix the defective parts.
Use the proper calibration gas.
Replace the sensor with a new one.

- 32 -

9. Product Specifications

9-1. Standard specifications

9

Product Specifications
9-1. Standard specifications<ATEX/IECEx/UKEX Specifications>
Model
Detection
principle
Gas to be
detected
Applicable gas
detector head
Detection
methodSampling
condition
Flow rate
Transmission
cable

GD-A80D-AS
Catalytic combustionor
new ceramic

GD-A80DV-AS

GD-A80DS-AS

GD-A80DN-AS

Semiconductor

Hot-wiresemiconductor

Thermal conductivity

Combustible gases in
the air

Combustible/toxic gasesin the air

Combust ble/toxic gasesin the air

Combustible gases in the
air/inert gas

GD-A80DGD-A80DV

GD-A80DS

GD-A80DN

Aspirator suction type
Equivalent to atmospheric pressure (compressed air: 0.1 - 0.7 MPa, maximum use amount: 3 L/min<converted into atmospheric pressure>)
0. 8 - 2 L/min
1. 25 or 2 mm2
CVV, 4-core or
CVVS, 3-core or
CVVS, 4-core or equivalentequivalentequivalent

Cableconnecting port

Pressure proof packing gland G3/4 [Rubber seal ID] Φ12 for mounted, Φ13 for attachedTubeconnecting port

GAS IN: Rc1/4 (O. DΦ8-1t)
Half-union for resin tube <material: PP> or
Half-union for copper tube <material: Bs> or
Half-union for stainless tube <material: SUS>GAS OUT: Rc1/4 (O. DΦ8-1t, half-union for copper tube)
Compressed air IN: Rc1/4 (O. DΦ8-1t, half-union for copper tube)

Operatingtemperatures*1
Operatinghumidities
Structure
Explosion-proof
structure
Explosion-proof
class
External
dimensions
WeightOuter color-20 - +53℃ (At a constant condition)
Below 95% RH (Non-condensing)
Wall mounting sampling unit (PP, Cu or SUS type)
Flame-proof enclosures
Ⅱ2G Ex dbⅡC T4 Gb (ATEX/UKEX)
Ex dbⅡC T4 Gb (IECEx)
Approx. 310 (W) x 200 (H) x 167 (D) mm (MC filter with flow monitor excluded)
Approx. 5.3 kg
Gas detector head: Munsell 7. 5BG5/2
Sampling unit: Munsell N-5. 0*1. The ambient temperature range which maintains a capability of explosion proof of the label on thedetector head is -40 to +53°C. However, the operating temperature range to maintain gas detection
performance is -20 to +53°C.

- 33 -

9. Product Specifications

9-1. Standard specifications<Japan Ex Specifications>
Model
Detection
principle
Gas to be
detected
Applicable gas
detector head
Detection
methodSampling
condition
Flow rate
Transmission
cable

GD-A80D-AS
Catalytic
combustion or
new ceramic
Combustible gasesin the air
GD-A80DGD-A80DV-AS

GD-A80DS-AS

GD-A80DN-AS

Semiconductor

Hot-wiresemiconductor

Thermal conductivity

Combustible/toxic
gases in the air

Combustible/toxic
gases in the air

Combustible gasesin the air/inert gas

GD-A80DV

GD-A80DS

GD-A80DN

Aspirator suction type
Equivalent to atmospheric pressure (compressed air: 0.1 - 0.7 MPa, maximum use
amount: 3 L/min <converted into atmospheric pressure>)
0. 8 - 2 L/min
1. 25 or 2 mm2
CVV, 4-core or
CVVS, 3-core or
CVVS, 4-core or equivalentequivalentequivalent

Cableconnecting port

Pressure proof packing gland G3/4 [Rubber seal ID] Φ12 for mounted, Φ13 for attached

Tube connecting
port

GAS IN: Rc1/4 (O. DΦ8-1t)
Half-union for resin tube <material: PP> or
Half-union for copper tube <material: Bs> or
Half-union for stainless tube <material: SUS>GAS OUT: Rc1/4 (O. DΦ8-1t, half-union for copper tube)
Compressed air IN: Rc1/4 (O. DΦ8-1t, half-union for copper tube)

Operatingtemperatures*1
Operatinghumidities
Structure
Explosion-proof
structure
Explosion-proof
class
External
dimensions
WeightOuter color-20 - +53℃ (At a constant condition)
Below 95% RH (Non-condensing)
Wall mounting sampling unit (PP, Cu or SUS type)
Flame-proof enclosures
Ex dⅡC T4 (Japan Ex)
Approx. 310 (W) x 200 (H) x 167 (D) mm (MC filter with flow monitor excluded)
Approx. 5.3 kg
Gas detector head: Munsell 7.5BG5/2
Sampling unit: Munsell N-5. 0*1. The ambient temperature range which maintains a capability of explosion proof of the label on thedetector head is -40 to +53°C. However, the operating temperature range to maintain gas detection
performance is -20 to +53°C.

- 34 -

10. Definition of Terms

10

Definition of Terms
Catalytic
combustion typeThis is a principle of the sensor installed in GD-A80D-AS.
See "9-2. Detection principle" for details.

New ceramicThis is a principle of the sensor installed in GD-A80D-AS.
See "9-2. Detection principle" for details.

Semiconductor

This is a principle of the sensor installed in GD-A80DV-AS.
See "9-2. Detection principle" for details.

Hot-wiresemiconductor

This is a principle of the sensor installed in GD-A80DS-AS.
See "9-2. Detection principle" for details.

Thermalconductivity

This is a principle of the sensor installed in GD-A80DN-AS.
See "9-2. Detection principle" for details.

Initial clear

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.

Full scale

Maximum value of the detection range.

% LEL

A unit that assumes the lower explosive limit of the combustible gas to be detected as
100.

Calibration

Adjusts the readings to the calibration gas concentration value by using thecalibration gas.

- 38 -