RKI Instruments GD-70D Series User manual

Gas Detector Head
GD-70D Series
Operating Manual
Part Number: 71-0446
Revision: P1
Released: 7/11/19
Request for the Customers
•Read and understand this operating manual before using the detector.
•You must operate the detector in accordance with the operating manual.
•Regardless of warranty period, we shall not make any compensation for accidents and damage
caused by using this product.
The compensation shall be made only under the warranty policy of products or parts
replacement.
•Because this is a safety device, daily and biannual maintenance must be performed.
•If you find abnormalities in the detector, please contact our local representative immediately.

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<Contents>
Request for the Customers.....................................................................................1
1Outline of the Product....................................................................................................4
1-1 Preface .............................................................................................................4
1-2 Product Purpose...............................................................................................4
1-3 Definition of DANGER, WARNING, CAUTION and NOTE ..............................5
1-4 Method of confirmation for CE marking type....................................................5
2Important Notices on Safety..........................................................................................6
2-1 Danger Statements...........................................................................................6
2-2 Warning Statements.........................................................................................6
2-3 Caution Statements..........................................................................................7
3Product Components.....................................................................................................8
3-1 Main Unit and Standard Accessories................................................................8
3-2 Outline Drawing................................................................................................9
3-3 Names and Functions for Each Part.................................................................10
3-4 Operation Diagrams .........................................................................................14
4Installation......................................................................................................................16
4-1 Requirements ...................................................................................................16
4-2 Precautions for Installation Sites ......................................................................16
4-3 Precautions for System Designing ...................................................................18
4-4 Proper use of alarm contact .............................................................................19
4-5 Installing the Detector.......................................................................................20
4-6 Wiring the Detector...........................................................................................22
4-7 Making Tubing Connections.............................................................................34
4-8 Disposal............................................................................................................35
5Operation.......................................................................................................................36
5-1 Preparation for Start-up....................................................................................36
5-2 Starting Up the Detector...................................................................................36
5-3 Turning Off the Detector ...................................................................................38
5-4 Basic Operation................................................................................................38
5-5 Modes .............................................................................................................39
6Detection Mode..............................................................................................................41
6-1 Gas Alarm Activation ........................................................................................41
6-2 Fault Alarm Activation.......................................................................................47
6-3 External Output Operation................................................................................47
6-4 Other Functions................................................................................................50
6-5 About LONWORKS (LN specification) .............................................................53
7Alarm Test Mode............................................................................................................57
7-1 Alarm Test Mode...............................................................................................57
8User Mode .....................................................................................................................59
8-1 User Mode........................................................................................................59
9Maintenance Mode........................................................................................................65
9-1 Environmental Setting 1 "2-9"...........................................................................70
9-2 Alarm Value Setting "2-9" - "SET 1"..................................................................71
9-3 Fault Alarm Test "2-9" - "SET 4" .......................................................................73
9-4 Environmental Setting 2 "2-10".........................................................................74
9-5 Date/Time Setting "2-10" - "SET 1" ..................................................................79
9-6 Energized/De-Energized Contact Setting "2-10" - "SET 6"..............................81
9-7 ETHERNET Setting "2-10" - "SET 18" .............................................................83
10 Maintenance..................................................................................................................86
10-1 Maintenance Intervals and Items ........................................................86
10-2 Calibration Overview ...........................................................................86
10-3 Calibrating with the Target Gas ...........................................................90
10-4 Calibrating with a Surrogate Gas (Sensors with Factors)...................93
10-5 Calibrating with a Gas Bag (Calibrating with HCl)...............................99
10-6 Calibrating with a Humidifier (MOS Sensors)......................................103
10-7 Calibrating a Pyrolyzer Unit.................................................................107
10-8 Flow Rate Adjustments........................................................................110
10-9 Replacing Parts ...................................................................................112

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10-10 Storing the GD-70D.............................................................................115
11 Troubleshooting.............................................................................................................116
12 Product Specifications...................................................................................................119
12-1 Common Specifications.......................................................................119
12-2 Specifications for Each Model.............................................................119
12-3 Specifications for Each Sensor Type...................................................120
12-4 Full Scale and Alarm Points.................................................................123
13 Calibration Parts List......................................................................................................126
14 Replacement Parts List .................................................................................................129
Warranty Policy .......................................................................................................142

GD-70D - 4 -
1
Outline of the Product
1-1 Preface
Thank you for choosing our GD-70D Series gas detector head. Please verify that the 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 detector properly. All users must read and understand the operating manual before using the
detector.
1-2 Product Purpose
•This is a fixed type gas detector head which detects gas leaks in semiconductor factories, etc.
•The gas detector is a safety device, not an analyzer or densitometer which performs quantitative/qualitative
analysis/measurement for gases. You must understand the features of the detector before using it, so that
you can use it properly.
•The detector detects abnormalities in the air caused by the presence of gas (or oxygen deficiency) with the
built-in gas sensor unit. The concentrations of detected gases are shown on the LCD.
•The built-in pump in the detector draws gas to perform gas detection.
•The detector has two-step gas alarm contact and fault alarm contact.
•The detector outputs the gas concentration in 4 - 20 mA or digital data.
•The communication method for each specification is as follows.
GD-70D
4 - 20 mA specification
Analog transmission
GD-70D-NT
NT specification
2-wire type DC power-line communication
GD-70D-EA
EA specification
Ethernet and analog transmission (4 - 20 mA)
GD-70D-LN
LN specification
LONWORKS

- 5 - GD-70D
1-3 Definition of DANGER, WARNING, CAUTION and
NOTE
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.
1-4 Method of confirmation for CE marking type
The CE marking is labeled on the detector in case of comply with CE marking. Please confirm the
instrument specification before using. Please refer to the Declaration of Conformity that is at the end of this
manual if you have CE marking type.
You can confirm instrument specification to see the CE marking as follows.
CE marking label (Back of front cover)
CE Marking

GD-70D - 6 -
2
Important Notices on Safety
2-1 Danger Statements
DANGER
This is not an explosion-proof device. You must not use it to detect gases exceeding the lower limit of explosion.
2-2 Warning Statements
WARNING
Power Supply
Before turning on the detector, always check whether the voltage is properly applied. Do not use an unstable
power supply because it may cause malfunctions.
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, check the protective functions for defects. When defects are found in the protective
functions, such as protective grounding, do not start the detector.
External connection
Before connecting the detector to external equipment or an external control circuit, securely connect it to a
protective grounding circuit.
Tubing
The detector is designed to draw gases around it under normal atmospheric pressure. If excessive pressure is
applied to the sampling inlet and outlet (GAS IN, GAS OUT) of the detector, detected gases may leak from the
flow system and pose dangers. Be sure that excessive pressure is not applied to the detector when it is used.
Detected gases must be exhausted from the outlet (GAS OUT) on the bottom of the detector to a safe place
using an exhaust tube.
Handling the sensor unit
Do not disassemble the electrochemical type sensor unit (ESU) or galvanic cell type sensor unit (OSU) because
they contain electrolyte. Electrolyte may cause severe skin burns if it contacts skin and may cause blindness if it
contacts eyes. It may discolor or damage clothing. If contact occurs, rinse the area immediately with a large
quantity of water.
Zero adjustment (AIR Adjustment) in the atmosphere
When zero adjustment (AIRAdjustment for oxygen deficiency alarm) is performed in the atmosphere, check the
atmosphere for freshness before beginning the adjustment. If other gases exist, the adjustment cannot be
performed properly and the detector will not properly detect gas.
Operation in a gas
Do not operate the detector in a place where flammable/explosive gases or vapors are present. Operating the
detector in such an environment will lead to extreme dangers.
Response to a gas alarm
Issuance of a gas alarm indicates that there are extreme dangers. Take proper actions based on your judgment.

Definition of Terms
- 7 - GD-70D
2-3 Caution Statements
CAUTION
Do not use a transceiver (walkie-talkie) near the detector.
Radio waves from a transceiver near the detector or its cables may disrupt detector operation. When using a
transceiver, it must be used in a place where it disturbs nothing.
Do not turn the detector on less than 5 seconds after it was turned off.
Restarting the detector less than five seconds after turning it off may cause errors.
Verify that the reading on the flow rate indicator corresponds to the specified flow rate before using the
detector.
If it does not correspond to the specified flow rate, gas detection cannot be performed properly. Be sure the flow
rate is stable.
Attach the dust filter before using the detector.
Before using the detector, attach the specified filter to prevent disturbances by possible gas absorption or air
dust.
The dust filter used depends on the gas being detected. For more information on dust filters, please contact RKI.
Observe the operating restrictions to prevent condensation inside the tube.
Condensation formed inside the tube causes clogging or gas absorption, which disturbs accurate gas detection.
Thus, condensation must be avoided. In addition to the installation environment, carefully monitor the
temperature/humidity of the sampled area to prevent condensation inside the tube. In particular, when detecting
a corrosive, water-soluble gas, such as a strong acid gas, the gas is undetectable and furthermore may corrode
internal parts. Please observe the operating restrictions.
Do not use the external output of the detector to control other devices.
This is not a control device. You are not allowed to use its external output to control other devices.
Do not disassemble/modify the detector, or change the settings unless necessary.
Disassembling/modifying the detector will invalidate the guarantee of the performance. Changing the settings
without understanding the specifications may cause alarm malfunctions. Please use the detector properly in
accordance with the operating manual.
Do not forget to perform regular maintenance.
Since this is a safety device, regular maintenance must be performed to ensure its safety. Continuing to use the
detector without performing maintenance will compromise the sensitivity of the sensor, thus resulting in
inaccurate gas detection.

GD-70D - 8 -
3
Product Components
3-1 Main Unit and Standard Accessories
<Main Unit>
<Standard Accessories>
•Operating manual
•Protective rubber cap (to be removed when using the
detector)
•Dedicated handling lever (for wiring)
•Dust filter
•Interference gas removal filter
(to be supplied with sensor units for certain gases)

- 9 - GD-70D
<Pyrolyzer Unit (PLU-70)(Option)>
* This is needed in “pyrolyzer + electrochemical type (ESU)” and “pyrolyzer + pyrolysis-particle type
(SSU)”.
For more information on the pyrolyzer unit (PLU-70), see the separate operating manual.
3-2 Outline Drawing
Pyrolyzer Unit
(Unit: mm)
M5 mounting hole
GAS IN
GAS OUT
Sensor unit display
Operating switch
Display
Protective cover for power switch
Screw for grounding earth rod
External wire hole
Connector for PLU
Connector for PoE
Power switch

GD-70D - 10 -
3-3 Names and Functions for Each Part
The detector consists of the following units.
<Front Panel and Character LCD>
Wall-mounted unit
Main unit
Pump unit
Sensor unit

MODE key
TEST/SET key
▲key
▼key

Lock lever

Sensor unit nameplate display window

Power lamp

First alarm lamp

Second alarm lamp

Fault lamp
⑪
Gas name display
⑫
Concentration
value display
⑬
Unit display
⑭
Concentration
bar indicator
⑮
Alarm setpoint
indicator
⑯
Flow rate
indicator
⑰
Communication
indicator
⑱
Maintenance
indicator
⑲
Inhibit indicator
⑳
Pyrolyzer unit
connection indicator
CAUTION
Each unit consists of precision parts. When a unit is detached, be careful not to drop it. Dropping
the unit compromises its original performance or causes malfunctions.

- 11 - GD-70D
①
MODE key
Used to enter User and Maintenance Mode.
It is also used to cancel or skip in a specific mode.
②
TEST/SET key
Used to enter the test mode.
It is used for confirmation in a specific mode.
③
▲key
Used to change screens or change a value (UP).
④
▼key
Used to change screens or change a value (DOWN).
⑤
Lock lever
Lever to lock the main unit. Push it to attach or detach the main unit.
⑥
Sensor unit nameplate
display window
Window to view information on the currently installed sensor.
⑦
Power lamp (POWER)
Power lamp. Turns green when the power is on.
⑧
First alarm lamp
(ALM1)
First alarm lamp. Turns red when the first alarm is reached.
⑨
Second alarm lamp
(ALM2)
Second alarm lamp. Turns red when the second alarm is reached.
⑩
Fault lamp (FAULT)
Fault lamp. Turns yellow when an abnormality is detected in the detector.
⑪
Gas name display
Displays the gas name in chemical formula (e.g. Silane = SIH4).
⑫
Concentration value
display
Displays the gas concentration.
⑬
Unit display
Displays the unit according to the specification (ppm, ppb, vol%, %, %LEL).
⑭
Concentration bar
indicator
The detectable range (full scale = FS) is divided into 20 segments. The
increase in concentration is displayed in proportion to the full scale.
⑮
Alarm setpoint
indicator
The alarm setpoints (AL1 and AL2) are indicated on the concentration bar.
⑯
Flow rate indicator
Displays the flow rate. When the line is in the middle of the indicator, the
flow rate is normal (0.5 L/min).
⑰
Communication
indicator
For GD-70D-NT, this indicator is displayed while transmitting data with the
upper unit (TX, RX).
⑱
Maintenance indicator
Displayed while in Maintenance Mode. When this indicator is displayed, the
alarm contact is disconnected and there are no alarms.
⑲
Inhibit indicator
Displayed when the inhibition (point skip) is set.
⑳
Pyrolyzer unit
connection indicator
Displayed when the dedicated pyrolyzer unit (PLU-70) is connected.
<Main Unit>
The main unit of the GD-70D houses the sensor unit, pump unit,
and circuitry for the detector. The main unit installs to the
mounting plate’s terminal plate.
<Pump Unit>
The pump unit gets installed in the main unit. It draws sample into the detector at 0.5 L/min.

GD-70D - 12 -
CAUTION
•The sensor unit must be handled carefully to ensure quality. When the sensor unit is stored, a
dedicated warehouse and power equipment for the sensor unit are needed. In principal, the sensor
unit must not be detached from the detector when it is handled or stored.
•Be sure that the sensor unit is installed properly.
If a sensor unit is of different specification or principle than the one shipped from the manufacturer, a
message will be displayed on the detector LCD (C-02).
If this message is displayed, make sure you are using the correct sensor unit.
•After the sensor unit is replaced, always perform a gas calibration (zero adjustment and span
adjustment).
<Mounting Plate>
The mounting plate gets installed to the installation site. The main unit connects to the mounting plate
using the 10-point terminal plate.
<Sensor Unit>
A sensor unit installed in the detector is the same regardless of
the detection principle which means sensor units are
interchangeable. Each sensor unit has a different color that
corresponds to the detection principle as shown below. Handling
of the sensor unit depends on the detection principle.
Mounting hole
10-point terminal plate: Connections for power supply,
signal cables and other external wires.
Locking lever: Locks the main unit to the mounting plate.

- 13 - GD-70D
Electrochemical
type (ESU)
•Do not disassemble the sensor unit because it contains electrolyte. If contact
occurs, rinse the area immediately with a large quantity of water.
•The sensor unit identifies the storage direction. Put the sensor unit in the
dedicated case while handling it. Do not place it on its side or upside-down.
•When a new sensor unit is installed, it must be warmed up.
Although warm-up time is different depending on the type of the installed
sensor, it is recommended that warm-up should be performed for three hours or
more. Please contact RKI for more information.
•The sensor unit must be stored in a clean, cool and
dark place away from direct sunlight. Some types of
the sensor units cannot be stored together with other
units. Please contact RKI for more information.
Pyrolysis-particle
type (SSU)
•Although the sensor unit contains radioactive materials, it is certified as a
specified designing certification device, which is regarded as a device
having no influences on health. Observe the "Safety Manual" which
stipulates conditions for the certification. To dispose of the sensor unit, you
must return it to us. You do not need to take any additional actions.
•The sensor unit contains a small amount of radioactive materials. Do not
disassemble it, or dispose of it like other wastes.
•The sensor unit must be put into the dedicated case specified by us, and
stored away from direct sunlight in a clean place
where the temperature and humidity are maintained
at a normal level and where appropriate measures
are taken to prevent the sensor from being taken out
easily.
•When the sensor unit is transported out of your
factory, please use a transportation company which
can handle specified designing certification devices
(L-type packages).
•For more information, see the "Safety Manual".
Semiconductor
type (SGU)
•Before using the sensor unit, it needs to be warmed up for a specified time.
The sensor unit is warmed up sufficiently in our factory before it is delivered to
you. Therefore, after you receive the sensor unit, please use it as soon as
possible so that unpowered time is minimized.
•The warm-up time before using the sensor unit is related to how long the
sensor unit was unpowered.
Unpowered time
Suggested warm-up time
SGU-8541 (H2)
SGU (Others)
10 minutes or less
10 minutes or more
2 hours or more
1 hour or less
30 minutes or more
2 hours or more
24 hours or less
1 hour or more
4 hours or more
72 hours or less
4 hours or more
24 hours or more
10 days or less
2 days or more
2 days or more
Less than 1 month
7 days or more
7 days or more
Less than 3 months
14 days or more
14 days or more
3 months or more
1 month or more
1 month or more
•To store the sensor unit in an unpowered state, it must be stored under
normal temperature/humidity in a clean place away from direct sunlight.
Dedicated case
Dedicated case

GD-70D - 14 -
Galvanic cell type
(OSU)
•Do not disassemble the sensor unit because it contains electrolyte. If contact
occurs, rinse the area immediately with a large quantity of water.
•The sensor unit must be stored under normal temperature/humidity in a clean
place away from direct sunlight.
3-4 Operation Diagrams
<Electric Diagram>
Sensor unit
Controller
(CPU)
Flow
sensor
Pump
POWER INPUT (24
VDC)
Power supply part
Gas alarm contact
(ALM1, ALM2)
Fault alarm contact
(FAULT)
* Standard setting of
contact activation
De-energized
(De-energized at a
normal state)
ON-ALARM
(Closed contact at
an alarm state)
Alarm contact controller
Transmitter
(4 - 20 mA/NT/
EA specification)
Pump
control
circuit
Amplifier
Controller
(CPU)
Display
(POWER) (ALM1) (ALM2)
(FAULT)
LCD
Operating unit
(MODE) (▲) (▼) (TEST/SET)
4 - 20 mA specification:
4 - 20 mA DC transmission
NT specification: Digital
data transmission
EA specification: Ethernet
and 4-20 mA DC
transmission
LN specification: confirm to
LONWORKS

- 15 - GD-70D
<Tubing Diagram>

GD-70D - 16 -
CAUTION
•This is a precision instrument. Because the detector may not provide the specified performance in
some places (environments), check the environment in the installation site, and then take
appropriate actions if necessary.
•Because the detector plays an important role for safety and disaster prevention, you must install as
many units of the detector as needed in appropriate points.
•Because gases may leak or collect in different areas depending on the types of gases and the
working areas, carefully consider how many units to install and where to install them.
4
Installation
4-1 Requirements
All users must follow the operating precautions. Ignoring the precautions may damage the detector,
resulting in inaccurate gas detection.
4-2 Precautions for installation sites
Do not install the detector in a place with
vibrations or shocks.
The detector contains sensitive electronic parts. The detector
must be installed in a stable place without vibrations or shocks
and where it will not fall.
Do not install the detector in a place exposed to
water, oil or chemicals.
Avoid installation locations where the detector is exposed to
water, oil or chemicals.
Do not install the detector in a place where the
temperature drops below 0ºC or rises over 40ºC.
The operating temperatures of the detector are 0 - 40ºC. The
detector must be installed in a stable place where the operating
temperatures are maintained and do not change suddenly.
CAUTION
•After you receive the detector, start using the detector within the specified operation start limit of the
sensor unit.

- 17 - GD-70D
Do not install the detector in a place exposed to direct
sunlight or sudden changes in the temperature.
Avoid installation locations where the detector is exposed to
direct sunlight or radiant heat (infrared rays emitted from a high-
temperature object), and where the temperature changes
suddenly. Condensation may form inside the detector, or the
detector cannot adjust to sudden changes in the temperature.
Keep the detector (and its cables) away from
noise source devices.
Avoid installation locations where high-frequency/high-voltage
exist.
Do not install the detector in a place where maintenance of the detector cannot be
performed or where handling the detector involves dangers.
Regular maintenance of the detector must be performed.
Do not install the detector in a place where the equipment must be stopped when maintenance is
performed, where parts of the equipment must be removed to perform maintenance, or where the detector
cannot be removed because tubes or racks prevent access to it. Do not install the detector in a place
where maintenance involves dangers, for example, near a high-voltage cable.
Do not install the detector in equipment which is not properly grounded.
Before installing the detector in equipment, the equipment must be grounded properly.
Do not install the detector in a place where other gases exist around it.
The detector must not be installed in a place where other gases exist around it.

GD-70D - 18 -
4-3 Precautions for System Designing
Using a stable power supply
The external output and alarm contact of the detector may be activated when the power is turned on, when
momentary blackout occurs, or when the system is being stabilized. In such cases, use a safety power
supply, or take appropriate actions on the receiving side.
The detector must be provided with the following power supply.
Power supply voltage
24 VDC
±
10% (the terminal voltage of the detector)
or PoE connection (GD-70D-
EA)
Allowed time of
momentary blackout
Up to 10 milliseconds (To
recover from a momentary
blackout longer than 10
milliseconds, restart the
detector.)
Example of actions
To ensure continuous operation and activation, install
a protective power supply outside the detector.
Others
Do not use it with a power
supply that has a large
power load or high-
frequency noise.
Example of actions
Use a line filter to avoid the noise source if
necessary.
Heat radiation designing
When it is installed in the closed instrumentation board, attach ventilation fans above and below the board.
Protecting 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 be
completely protected from a power surge caused by lightning. Although complete elimination of disasters
caused by lightning is impossible, the following protective measures can be taken.
Protection against
lightning
Take appropriate measures in accordance with the importance of the facilities
and the environment.
•Connect the transmission signal route by using optical fiber.
•Provide protection by a lightning arrester (cable safety retainer).
(Although inductive lightning surge can be transmitted through the cable, it
is prevented 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.)
Grounding
In addition to lightning, there are more sources of surge noise. To protect
devices from these noise sources, the devices 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.
CAUTION
•An unstable power supply and noise may cause malfunctions or false alarms.

- 19 - GD-70D
4-4 Proper use of alarm contact
The alarm contact of the detector is used to transmit signals to activate an external buzzer, alarm lamp or
rotating lamp. Do not use the detector for controlling purpose (e.g., controlling the shutdown valve).
The specifications for the alarm contact of the detector are based on the resistive load conditions. If
inductive load is used at the alarm contact, the following errors will occur easily because counter
electromotive force is generated at the contact.
•Deposition, defective insulation or defective contact at the relay contact
•Damage of any electric parts due to high-voltage generated inside the detector
•Abnormal operations by an out-of-control CPU
If load is to be activated, appropriate measures must be taken to stabilize the operation of the detector and
protect the alarm contact referring to the following information.
•Relay it with an external relay at 100 VAC or lower (contact amplification). At the same time, the surge
absorbing part, SK1, suitable for the specifications must be attached to the external relay.
•In addition, the surge absorbing part, SK2, must be attached to the loaded side of the external relay if
necessary.
•It may be recommended that the surge absorbing part be attached to the contact for certain load
conditions. It must be attached to an appropriate position by checking how the load is activated.
GD-70D
SK1
SK2
Alarm
Contact
Power
supply
Power
supply
External relay
(low voltage relay)
* SK1, SK2: Surge absorbing parts
CAUTION
•The b contact (break contact) under de-energized state may be opened momentarily by a physical
shock, such as external force.
•When the b contact is selected for the alarm contact, take appropriate actions to prepare for a
momentary activation by adding signal delay functionality (approximately one second) to the
receiving side of the b contact.
CAUTION
•In principal, do not activate inductive load at the alarm contact of the detector. (In particular, never
use the inductive load to activate a fluorescent lamp or motor.)
•If inductive load is activated, relay it with an external relay (contact amplification). However, because
the coil of an external relay also involves inductive load, select a relay at a lower voltage (100 VAC or
below), and then protect the contact of the detector with an appropriate surge absorbing part, such
as a CR circuit.
Coil
Load

GD-70D - 20 -
4-5 Installing the Detector
NOTE
To use the pyrolyzer unit (PLU-70), also refer to the individual operating manual.
<Detector Dimensions and Maintenance Space>
CAUTION
•Before installing the detector, remove the protective rubber caps from the GAS IN and GAS OUT
fittings. If the detector is turned on while the rubber caps are still in place, the pump and sensor may
be damaged. Do not forget to remove the caps.
Leave space for the crosshatched area when installing the detector.
The crosshatched space represents necessary maintenance space.
CAUTION
•Multiple detectors installed in the same location must be installed at least 5 mm apart. It is
recommended that they be 10mm apart.
•When you install more than one detector in the same location, install them in a rack or on a wall that
is not affected by vibrations.
When the detectors are installed side-by-side, if the rack or wall in which the detectors are installed
does not have enough strength, vibrations from the pumps inside the detectors can cause
resonance between them. In this case, take preventive actions like reinforcing the rack or wall.
Maintenance space
Maintenance space
Maintenance space
Maintenance space
Maintenance space
Maintenance space
When installing using 2 screws
When installing using 3 screws
(Unit: mm)
(300)
(90)
(300)