CGS MERLIN GDPX+ Owner's manual

Installation & Operation Manual Merlin GDPX+
IOM Iss: 2 03-22 1
MERLIN GDPX+
Addressable Safe Area Gas Detector-TFT Controller
 Installation, Operation & Maintenance
Please read this manual carefully and retain for future use.
CGS provide a range of detection panels which can be used in many applications such as factories, car parks,
shopping centres and boiler houses. The GDPX+ can be used with up to sixteen (16) TFT range gas detectors in a
single cable run for monitoring and detecting gas in zones considered safe including CO, LPG and methane.
The information contained within this manual should be referenced for typical installation and operation only.
For specific requirements that may deviate from the information in this guide –contact your supplier.

Installation & Operation Manual Merlin GDPX+
IOM Iss: 2 03-22 2
Contents
Important Warning Statements.................................................................. 3
Installation................................................................................................... 4
Typical Application, Location & Positioning .................................................................4
Access & Mounting......................................................................................................5
Internal Board Overview..............................................................................................5
Board Connections Overview ......................................................................................6
Wiring your Detector....................................................................................................7
Creating a Detector Chain ...........................................................................................7
Detector ID Switches ...................................................................................................8
120ohm Termination Resistance –Detector Chains....................................................8
BMS MODBUS.............................................................................................................9
120ohm Termination Resistance –BMS MODBUS .....................................................9
MODBUS Data Settings ...............................................................................................9
Configuration Settings ...............................................................................................10
Settings Options Explained........................................................................................10
Factory Set Condition ................................................................................................11
Trouble Shooting .......................................................................................................11
Operation .................................................................................................. 12
First Power Up (Commissioning) ...............................................................................12
Main Screen...............................................................................................................12
Zone Status................................................................................................................12
Zone Screens.............................................................................................................12
Diagnostic Screen......................................................................................................13
Alarm Messages ........................................................................................................13
General Maintenance ............................................................................... 14
Cleaning.....................................................................................................................14
Manual Circuit Simulation Test ..................................................................................14
Service Reminders.....................................................................................................14
Bump Test (Gas Response Check)............................................................................14
Standard Test Gases .................................................................................................15
Bump Test Procedure................................................................................................15
Reset Service Message .............................................................................................16
End of Operational Life (EOL)....................................................................................16
Specification............................................................................................. 19

Installation & Operation Manual Merlin GDPX+
IOM Iss: 2 03-22 3
Important Warning Statements
Please take the time to thoroughly read these instructions which should be retained for future reference.
Detectors are shipped pre-calibrated and configured.
The expected lifetime of a gas sensor is 3-10 years upon initial power up dependant on your target gas and environmental
factors. The device will display a message to indicate this time and should immediately be replaced.
It is recommended that this device be commissioned upon installation and serviced annually by a competent person.
Do not apply lighter gas or other aerosols to the device –this will cause extreme damage to the sensors.
High concentrations of alcohol found in many products may damage, deteriorate or affect the gas sensing elements.
This device is designed to detect the gas type displayed on the screen only.
It is not designed to detect smoke, fire or other gases and should not be used as such.
This device provides early warning of the presence of gas, usually before a healthy adult would experience symptoms. This
warning is possible provided your alarm is installed and maintained in accordance with this manual.
Never ignore your device when in alarm.
This device requires a continual supply of electrical power –it will not work without power.
This device should not be used to substitute proper installation, use and/or maintenance of fuel burning appliances
including appropriate ventilation and exhaust systems.
Multiple detectors may be required to adequately protect property and persons.
This device does not prevent dangerous gasses from occurring or accumulating.
Actuation of your alarm indicates the presence of dangerous levels of gas.
The device is not intended for use in potentially explosive atmospheres.
Seek fresh air supply and contact your local gas emergency service should you suspect a gas leak.
This unit may not fully safeguard individuals with specific medical conditions. If in doubt, consult a doctor/physician.
Your product should reach you in perfect condition, if you suspect it is damaged, contact your supplier.
Manufacturer’s Warranty
Warranty coverage: The manufacturer warrants to the original consumer purchaser, that this product will be free of defects in
material and workmanship for a period of three (3) years from date of purchase or one (1) years for oxygen detectors.
The manufacturer’s liability hereunder is limited to replacement of the product with repaired product at the discretion of the
manufacturer. This warranty is void if the product has been damaged by accident, unreasonable use, neglect, tampering or other
causes not arising from defects in material or workmanship. This warranty extends to the original consumer purchaser of the
product only. Warranty disclaimers: Any implied warranties arising out of this sale, including but not limited to the implied
warranties of description, merchantability and intended operational purpose, are limited in duration to the above warranty period. In
no event shall the manufacturer be liable for loss of use of this product or for any indirect, special, incidental or consequential
damages, or costs, or expenses incurred by the consumer or any other user of this product, whether due to a breach of contract,
negligence, strict liability in tort or otherwise. The manufacturer shall have no liability for any personal injury, property damage or any
special, incidental, contingent or consequential damage of any kind resulting from gas leakage, fire or explosion. This warranty does
not affect your statutory rights. Warranty Performance: During the above warranty period, your product will be replaced with a
comparable product if the defective product is returned together with proof of purchase date. The replacement product will be in
warranty for the remainder of the original warranty period or for six months –whichever is the greatest.
Information on waste disposal for consumers of electrical & electronic equipment.
When this product has reached the end of its life it must be treated as Waste Electrical & Electronics Equipment (WEEE). Any
WEEE marked products must not be mixed with general household waste, but kept separate for the treatment, recovery and
recycling of the materials used. Please contact your supplier or local authority for details of recycling schemes in your area.
At the end of their working life, electrochemical sensors for oxygen and carbon monoxide detectors should be disposed of in an
environmentally safe manner. Alternatively they can be securely packaged and returned to CGS clearly marked for disposal.
Electrochemical sensors should not be incinerated as this may cause the cell to emit toxic fumes.

Installation & Operation Manual Merlin GDPX+
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Installation
Typical Application, Location & Positioning
The Merlin GDPX+ is a multi-safe zone gas detection panel which can be used in many applications such as factories,
car parks, shopping centres and most commonly - boiler houses. It can be used with up to sixteen Merlin gas
detectors (TFT range) for monitoring and detecting gas including carbon monoxide, liquid petroleum gas and
methane. The controller panel can be integrated with, but not limited to, a BMS (building management system)
including MODBUS, a fire panel, external alarms and remote emergency shut-off buttons.
Locations for detectors will vary based on the intended application and target gas, they should be located near
identified sources of a potential gas leaks/ pockets where hazardous gas could quickly accumulate and areas of
identified consequential risk. The composition of the target gas and its density relative to air are used as the basis for
any recommended height of detector placement. Generally, the installation height of a detector for a heavy gas (such
as propane) would be close to the lowest point in the area, and for a light gas (such as methane) would be close to
the highest point in the area. Any recommended heights may vary based on air flow and temperature conditions in
addition to the proposed application and location –this is particularly apparent with oxygen depletion sensors, and the
target gas that they are used for.
Target Gas
Typical Position
Natural Gas/Methane (NG)
High Level - 300mm (1ft) from ceiling
Liquid Petroleum Gas (LPG)
Low Level - 300mm (1ft) from ground level
Carbon Monoxide (CO)
Breathing Zone - 1700mm (5ft 6”) from ground level
Hydrogen (H)
High Level - 300mm (1ft) from ceiling
Oxygen (O2)
*Breathing Zone - 1000-1500mm (3 - 5ft) from ground level
* If you are installing and monitoring Oxygen depletion –consider the density of gas for its application and position
the detector accordingly i.e. ground level for high density gases.
The control panel should be located away from the area that it is monitoring and accessible is for both status
observation and alarm purposes. The control panel should be located outside of the hazardous area that it is
monitoring. Easy access is required both for status observation and alarm purposes.
Where detector cable runs may exceed 100 yards from one control panel –Contact your supplier!
The use of sound strobes are highly recommended!
Refer to your detector manual for further information regarding coverage, location and positioning including
areas and conditions to avoid!

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Access & Mounting
Unpack all the parts!
Designed for surface mounting, it must be installed by a licensed, insured contractor or competent person.
Carefully remove the front cover from the unit by unscrewing the four bolts
located at each corner. To do this –use the socket wrench provided. Mark
the four screw holes located on the back of the enclosure to the wall and
ensure the wall surface is flat to prevent base distortion.
After executing the mounting and the connections –replace the front cover
and insert the security caps over the four bolts.
Access to the interior of the panel, when carrying out any work, must be conducted by a competent person.
Before carrying out any work ensure local regulations and site procedures are followed.
We recommend all Merlin gas detection equipment and systems are commissioned by a competent/trained
engineer to ensure correct installation and operation. Contact CGS for more information.
Internal Board Overview
Note: Terminal blocks are plug/socket type and may be removed to ease wiring.
Be careful when creating access for cables –Damage to circuit boards will void any warranty!
Detectors must be earthed/grounded for electrical safety and to limit the effects of EMC or R/F interference.
For MODBUS communications, a shielded cable is used!
Detectors are shipped pre-calibrated and configured!

Installation & Operation Manual Merlin GDPX+
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Board Connections Overview
POWER/LINE IN
100-120vac mains power is supplied to the [POWER/LINE IN] connector using a 3-core cable fused at 3A. On
connecting the mains supply to the panel the power LED indicator will light up –this is located on the front.
VALVE OUT
100-120vac electrical power output from the [VALVE OUT] terminal using a 3-core cable to a gas solenoid valve,
which can shut the gas supply on alarm status.
ELECTRIC CONTACTOR
100-120vac electrical power output from the [ELECTRIC CONTACTOR] terminal using a 3-core cable, which will
isolate electrics in conjunction with the gas supply/line on alarm status.
BMS OUTPUT
Connections are available on the board for Building Management Systems. These are volt free connections.
This is a relay that changes state in alarm or when the gas is on/off and can be used in conjunction with the 24vdc
output and other external relays that affect other devices and controls such as purge fans and audible alarms etc.
PRESSURE SENSOR
The sensor wired to the [PRESSURE SENSOR] connector is screwed into the downstream port of the gas solenoid
valve. Wire sensor as follows: Red [+] Black [-] Blue [IN].
The sensor will monitor the gas supply pressure and if the pressure drops below 12mbar (0.17psi), the gas valve will
close as this could mean a gas leak is present. The sensor operating pressure is 0-100mbar (0–1.45psi).
DETECTOR CHAIN 24vdc power supply and MODBUS communication data cables are wired up to sixteen detectors,
chained in parallel up to approx. 100 yards from the panel depending on the chain configuration, wire type for power
and condition. For more information, see section: Wiring your detector.
BMS MODBUS
Connections for Master/Slave protocols used in Building Management Systems to communicate between devices
including the GDPX+ panel are used with [BMS MODBUS] –RTU.
SOUNDER-STROBE
There are connections for an external sounder alarm/ strobe lighting to activate on alarm.
24V DC OUTPUT
This is a permanent 24V DC power output for external auxiliary devices. Max output: 200mA
INPUT 1 & INPUT 2
These terminals are connections for selectable external devices, which send an ‘open/close’ circuit signal to the GDP-
X panel such as a current monitor, CO2 monitor, or extra emergency shut buttons and heat sensors - selectable in
the settings menu.
FIRE PANEL
An open/close switch for fire alarms detailed on the circuit board as [FIRE PANEL].
HEAT SENSOR
An open/close switch for heat sensors/ thermal links detailed as [HEAT SENSOR].
EM STOP
An open/close switch for remote emergency shut-off buttons detailed on the circuit board as [EM STOP].

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Wiring your Detector
24vdc power and MODBUS communication cables are wired to terminals marked [DETECTOR CHAIN + - D+ D-].
[SHEILD WIRE] detector terminals are used for earthing/grounding and shield wires connected to any earth/ground
terminal on the control panel. Twist the shield wire to avoid stray shield wires. If the detector does not have dedicated
shield wire terminals, shield wires connect to the 24vdc negative terminal [-] on both detector and panel.
A shielded and twisted 2 or 4 core cable is used to wire the MODBUS
terminals [D+ & D-). The shielding can be of 2 types: braided [mesh of thin
conducting wires] or foil (consisting of a thin sheet of metal covering the
twisted wires). One example of such cable is BELDEN 3082A. Any cable with
similar characteristics can be used to connect all the devices together.
If you are encountering noise or irregular problems with a bus link, the problem is likely related to grounding,
incorrect shielding or wiring mains power cables next to data cables.
The detector must be earthed/grounded for electrical safety and limit the effects of R/F & EMC interference!
Where cable runs may exceed 100 yards from one control panel –Contact your supplier!
Ensure the 120-ohm termination resistance switch is turned on at each end of a cable run!
Creating a Detector Chain
Create a detector chain by connecting detectors in a parallel (daisy chain) method.
Any other way may cause issues or damage to the overall system. Resistor switches should be turned on at each end
of a chain –see section ‘120ohm Termination Resistance’.
Single Detector Chain from
Control Panel example.

Installation & Operation Manual Merlin GDPX+
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Split Detector Chain from Control Panel example.
Reversing the [D+] and [D-] connections of any device can lead to the whole system to stop working owing to reverse
polarity found on the terminals. In order to avoid this problem, it is recommended that the cable of same colour
should be used to connect all [D+] terminals together and similarly cable of same colour to be used to connect all [D-]
terminals together.
The detector must be earthed/grounded for electrical safety and limit the effects of R/F & EMC interference!
Where cable runs may exceed 100 yards from one control panel –Contact your supplier!
Ensure the 120-ohm termination resistance switch is turned on at each end of a cable run!
Detector ID Switches
When wiring multiple detectors it is important to identify each detector installed for
the control panel to receive and display accurate data corresponding with the
correct device.
The ID configuration diagram is printed onto detector boards for quick
reference as shown opposite. All detectors are factory set to ID1.
We recommend a plan, map and/or marking the detector enclosures detailing ID and location!
ID Switches must be configured for each detector connected to receive and display accurate data!
120ohm Termination Resistance –Detector Chains
Signal communication issues may occur where the bus length is too long, high baud rates are
used or signal reflections are occurring. To avoid this, terminating at each end of a chain
may help the quality of the data signal by turning on the 120-ohm terminal resistor switch.
If a split chain is used, terminate the last detector in each chain.
If a single chain is used, terminate the first device (Panel) and last device (Detector).
Split chain Single chain

Installation & Operation Manual Merlin GDPX+
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BMS MODBUS
BMS MODBUS for master/slave protocols used in building management systems to communicate between devices
including the GDPX+ panel used with [BMS MODBUS] terminal.
A shielded and twisted cable is used. Any cable with similar
characteristics is used.
The shielding can be of two types: braided [mesh of thin conducting
wires] or foil (consisting of a thin sheet of metal covering the twisted
wires). If you are encountering noise or irregular problems with a
Modbus link, the problem is likely related to grounding, incorrect
shielding or wiring mains power next to Modbus wiring.
120ohm Termination Resistance –BMS MODBUS
Signal communication issues may occur where the bus length is too long, high baud rates are used or signal
reflections are occurring. To avoid this, terminating at each end of a chain may help the quality of the data signal by
turning on the 120-ohm BMS terminal resistor switch. Terminate the first and last device in each chain.
MODBUS Data Settings
Panel Address Selectable (Default 1)
Baud rate Selectable (Default 19200)
Data bits 8
Stop bits 2
Parity None
Function code 03 (Read Holding Register)
Start address 0 (40001)
No. of registers
(coil)
5
Data format 16-bit unsigned integral number
0 (40001) Panel Status
1 (40002) Panel Zones Status
2 (40003) Panel Alarm Status
3 (40004) Detector X Alarm code
4 (40005) Gas Pressure (mbar)
MODBUS SETUP
DATA SETUP
03 (Read Holding Register)
1 = GOOD
2 = PRE-ALARM
3= ALARM
0 = DISABLED
1= OK Zone1 Zone2 Zone3 Zone4
2 = ATTENTION 1 2 0 3
3= DANGER (OK) (ATTENTION)(DISABLED) (DANGER)
0 = GOOD (No Alarm)
2= Fire Panel Alarm
3= Heat Sensor Alarm
4 = Detector
5= Emergency Shut Off
6 = Low Pressure Alarm
7= INPUT 1 Alarm
8 = INPUT 2 Alarm
11 = Detector X ID 1 Alarm
12 = Detector X ID 2 Alarm
13 = Detector X ID 3 Alarm
14 = Detector X ID 4 Alarm
15 = Detector X ID 5 Alarm
16 = Detector X ID 6 Alarm
17 = Detector X ID 7 Alarm
18 = Detector X ID 8 Alarm
19 = Detector X ID 9 Alarm
20 = Detector X ID 10 Alarm
21 = Detector X ID 11 Alarm
22 = Detector X ID 12 Alarm
23 = Detector X ID 13 Alarm
24 = Detector X ID 14 Alarm
25 = Detector X ID 15 Alarm
26 = Detector X ID 16 Alarm
63 = Detector X ID 3 Fault
64 = Detector X ID 4 Fault
65 = Detector X ID 5 Fault
66 = Detector X ID 6 Fault
71 = Detector X ID 11 Fault
72 = Detector X ID 12 Fault
67 = Detector X ID 7 Fault
68 = Detector X ID 8 Fault
69 = Detector X ID 9 Fault
116 = Detector X ID 6 Lost
Panel
Status
Zone
Status
Zone Status Example
Alarm
Status
61 = Detector X ID 1 Fault
62 = Detector X ID 2 Fault
Alarm
Code
76 = Detector X ID 16 Fault
73 = Detector X ID 13 Fault
74 = Detector X ID 14 Fault
75 = Detector X ID 15 Fault
70 = Detector X ID 10 Fault
111 = Detector X ID 1 Lost
112 = Detector X ID 2 Lost
113 = Detector X ID 3 Lost
114 = Detector X ID 4 Lost
115 = Detector X ID 5 Lost
123 = Detector X ID 13 Lost
124 = Detector X ID 14 Lost
125 = Detector X ID 15 Lost
126 = Detector X ID 16 Lost
117 = Detector X ID 7 Lost
118 = Detector X ID 8 Lost
119 = Detector X ID 9 Lost
120 = Detector X ID 10 Lost
121 = Detector X ID 11 Lost
122 = Detector X ID 12 Lost

Installation & Operation Manual Merlin GDPX+
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Configuration Settings
On the circuit board is a settings dip-switch, when turned on, the screen will display the settings menu and the system
can be configured. The GDPX+ has a touch screen, which allows the engineer/ user to configure the system. There
are two menu screens, selectable by touching either page number [1] or [2].
Adjust Screen Brightness.
Press or slide the cursor up and down.
Change/Select Option
Press the blue option box or press and hold.
When the system is configured turn the [Settings] switch off and the system will automatically save and restart.
To view, change and save settings, you must provide mains power!
Access to the interior of the detector, when carrying out any work, must be conducted by a competent person!
Before carrying out any work ensure local regulations and site procedures are followed!
Settings Options Explained
FUNCTION
OPTION
Explanation
BMS relay ON/OFF for-
- Gas
- Error
Gas changes relay state with gas valve status only.
Error changes relay state upon all alarm messages.
Auto Start-
- ON
- OFF
In the event of a power loss, the system will restart automatically when restored or not.
Modbus Address-
- 1-32
GDPX+ panel address form master BMS Modbus.
Modbus Baud Rate-
- 9600
- 19200
- 38400
- 57600
- 115200
Modbus data exchange speed (bit per second).
FAB Auto Reset
- ON
- OFF
ON: System resets with the fire panel automatically following fire panel alarm.
OFF: Manually reset system following fire panel alarm.
INPUT 1 name-
- FAN
- NG
- CO
- LPG
- CO2
- EM
- HS
External devices connected to [INPUT 1] terminal. Fans (Fan), Gas detectors (NG, CO,
LPG, CO2), external emergency stop buttons (EM) or heat sensors (HS).

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INPUT 2 name-
- FAN
- NG
- CO
- LPG
- CO2
- EM
- HS
External devices connected to [INPUT 2] terminal. Fans (Fan), Gas detectors (NG, CO,
LPG, CO2), external emergency stop buttons (EM) or heat sensors (HS).
FAB timeout-
- 15 min
- 30 min
- 45 min
Time that the Fire Alarm Bypass (FAB) feature will be enabled upon each activation.
Fill time
- OFF
- 5 sec
- 10 sec
Time (seconds) the gas valve is open to fill the gas line on power up or reset.
Note: Prove time must be selected.
Prove time-
- OFF
- 30 sec
- 50 sec
Time (seconds) that the system tests the gas line for leaks on power up or reset.
Note: Fill time must be selected.
Factory Set Condition
BMS relay ON/OFF for-
- Gas
Auto Start-
- OFF
Modbus Address-
- 1
Modbus Baud Rate-
- 19200
FAB Auto Reset-
- OFF
INPUT 1 name-
- FAN
INPUT 2 name-
- FAN
FAB timeout-
- 30 min
Fill time-
- 5 sec
Prove time-
- 30 sec
Trouble Shooting
Fault.
Possible Cause/Correction.
Detector not responding.
Incorrect wiring.
ID switches not properly configured.
Termination switches not set up correctly.
Service message
Detector requires service –contact supplier.
End of Life message
Detector requires replacement –contact supplier.
No internet connection
Contact internet provider.
Reset GDPX+.
Gas proving not working
Fill time or gas proving not selected in menu. Both must be ON.
Pressure Sensor not connected to downstream port of gas valve.

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Operation
First Power Up (Commissioning)
On connecting mains power, the GDP2X panel will ‘warm up’ for approximately 60 seconds –
during this time the screen will display an ‘initialisation’ message while system searches for
detectors wired to the system.
We recommend all gas detection systems be commissioned by a competent/trained engineer to ensure
correct installation and operation!
Main Screen
When the system has finished initialising –the main screen will appear.
The main screen gives an overview of the status of each zone monitored by gas
detectors and if the gas line/supply is on (open) or off (shut).
Zone Status
Zone Status
System Condition
ZONE… OK
Gas levels are safe.
No error conditions.
ZONE… ATTENTION
Detector(s) are in pre-alarm status or
Detector(s) require service or
Detector gas sensor(s) end of life.
ZONE… DANGER
Dangerous gas levels have been detected or
Detector gas sensor fault has been detected or
Detector has lost its signal with the control panel.
See section: Alarm Messages.
ZONE… DISABLED
No detector signals received from the zone.
ZONE… -- X --
Detector not installed or Detector not configured correctly.
Zone Screens
Switch between zone screens by touching the relevant zone screen, i.e. [Z1], [Z2], [Z3] and [Z4].
Each zone can display up to 4 detectors as follows and include the status of alarms and gas levels for each detector:
a. ID: The detector identification number.
b. Serial Number: The unique serial number for that detector.
c. Gas: The target gas that the detector is monitoring.
d. Status: The status of gas levels, errors and messages.
e. Value: The concentration value of gas monitored.

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Diagnostic Screen
Press the (D) tab on screen to display system diagnostics.
Gas Pressure The pressure sensor connected to the gas solenoid valve will send this
data to the panel. If the pressure drops below 12mbar (0.17psi), the system will enter
an alarm state after a ten-second delay, as there may be a risk of a gas leak.
If proving is off the pressure will not be displayed.
Fire Alarm Bypass (FAB) This is an enable/disable feature where fire alarm tests may be required. To enable the
FAB feature select the press the off/on button shown where prompted to confirm the action prior to activation. The
FAB feature is displayed on screen when enabled. The system will return to normal at the end of the pre-selected
time of 15, 30 or 45 minutes configured in the settings. You can manually disable the FAB by pressing the blue option
box to OFF on the diagnostic screen.
Internet Connection status is currently unavailable.
Alarm Messages
When a detector goes into alarm state, the control panel isolate the gas supply and the screen will display the ID of
the detector in alarm. If two or more detectors enter alarm status, the first detector to send an alarm signal to the
control panel is displayed in the top left hand corner of the screen. Press the relevant zone page for detector
information. There are three types of detector alarm.
Detector Alarm ID: #
Dangerous gas levels detected, the control panel will display an ‘Alarm’ message and detector ID.
Detector Fault ID: #
If the control panel receives a fault signal from a detector, your panel will show a ‘Fault’ message and detector ID.
Detector Lost ID: #
If a detector loses communication with the control panel, the screen will show a ‘Lost’ message.
External Panel Connection Alarms
Alarm messages prompted from external devices connected to relevant open/close terminals on the internal board
i.e. remote emergency shut off buttons are visible when in alarm state. The gas supply will isolate (be shut off) and no
gas detection details will be available. After the cause of alarm is rectified, press the reset button.
Alarm messages from terminals [INPUT 1] or [INPUT 2] will depend on the name
selected in the settings. For example, if CO is the selected input the alarm message
will display “CO sensor alarm”. If [FAN] is the selected input, you will see “fan fault”.
All alarm screens will show the input terminal used i.e. Input 1 or Input 2.
Low pressure and fan alarms have a ten-second delay!
All alarms will isolate the gas supply/line and electrics if using an electrical contactor and configured to do so!
Pressing mute on the panel will silence the audible alarm buzzer on the panel!

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General Maintenance
Cleaning
Concentrations of alcohol found in many products may damage, deteriorate or affect the gas sensing elements such as;
wine; deodorants; stain removers and thinners. Other gases and substances to avoid are corrosives (i.e. chlorine &
hydrogen chloride); alkali metals; basic or acidic compounds; silicones; tetraethyl lead; halogens and halogenated
compounds!
Keep your gas detector in good working order - follow these basic principles.
•Remove any dust/debris from the outer enclosure regularly using a slightly damp cloth.
•Never use detergents or solvents to clean your device.
•Never spray air fresheners, hair spray, paint or other aerosols near the device.
•Never paint the device. Paint will seal vents and interfere with the device.
Manual Circuit Simulation Test
Access to the interior of the detector, when carrying out any work, must be conducted by a competent person!
This circuit test does not check the gas-sensing element itself!
When the test button on the circuit board is pressed and held the detector will simulate an open
circuit to ensure configured systems, outputs, alarms, indications, and other external devices operate
as intended in response to gas. When the test button is released –the test sequence will terminate
and return to normal operation.
Service Reminders
A service screen will intermittently flash every 30 seconds after one year of operation.
The annual message reminder will begin after five (5) hours of continuous power irrespective of whether
the system is then, used intermittently. The detector will still operate as intended during this time.
Depending on the application and environmental factors, a service (bump test) can be conducted at a higher
frequency determined by the end user but must be executed by a competent person.
Bump Test (Gas Response Check)
What is a Bump Test?
Gas response checks are often referred to as a ‘bump test’. Bump tests are important to make sure a device is able to
detect a release of gas as early as possible. The aim of the bump test is to make sure a detector is working at its
optimum by briefly exposing the unit to a known concentration of the target gas that usually exceeds the highest
alarm point. If the detector goes into alarm and all signals/outputs activate, then the system is working safely.
If the system fails to operate as intended in an alarm state, the gas detector must not be used until a full inspection
and service has been conducted.
Why is it important?
A detector may visually appear in good working order, but its sensitivity and accuracy can be inhibited by external
factors. Dust, humidity, temperature fluctuations, cleaning products, contaminants, exposure to its target gas or
sensor drift (ageing) can cause a decline in sensitivity, accuracy and eventual failure.
How often?
Regular bump tests are important to make sure the detector is able to detect a release of gas as early as possible and
usually takes seconds (gas type dependant i.e. CO sensors will take over a minute) and is often completed alongside
a scheduled fire alarm test, however the frequency should be determined following an appropriate risk assessment by
the end user.

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We recommend testing detectors every 12-18 months along with the regular fire test procedures and coincide with
the annual service message prompted on the detection system after each year of service/operation.
What do I need?
Contact your CGS representative for details of suitable bump testing kits and gases. Kits usually consist of a certified
gas cylinder or spray. We recommend only using CGS calibration gas kits to ensure correct flow rates meet CGS
technical requirements. A bump testing gas is usually a concentration mix that exceeds the highest alarm set point.
Standard Test Gases
All certified test gases supplied by CGS are classified as non-flammable and non-toxic, however, they do contain gas
under pressure and may explode if heated to extreme temperatures and cause asphyxiation in high concentrations.
See below for recommended gas concentrations for bump testing your detector.
Detector Type
Standard Test Gas
CO - Carbon Monoxide
350 - 500ppm (balance in air).
NG - Methane
0.6 - 0.8% BV (balance in air)
LPG - Liquid Petroleum Gas
0.3 –0.4% BV (balance in air)
H - Hydrogen
5000 - 6000ppm (balance in air)
O2- Oxygen
15% (balance in Nitrogen).
CO2–Carbon Dioxide
>4500ppm or Breath on Sensor
Bump Test Procedure
To increase reaction time, cover the escape vents at the top of the device.
For more help and advice on bump testing –contact us.
Always remove the regulator/valve from cylinder after use!
Always check cylinder pressure upon sealing valve –there may not be a sufficient amount of gas!
All CGS cylinders will re-seal upon removal of the regulator/valve!
Always give at least five (5) minutes between testing the same unit or until gas has fully dispersed!
Always consider safety and use equipment in accordance with Safety Data Sheets!
STEP 1
Activate Controller Service Mode –GDP2X & GDPX+
This will inhibit all alarms/outputs and signals for fifteen (15) minutes!
If you are testing all actuation of alarms/outputs and signals please proceed to Step 2!
•Access service mode by pressing the CGS logo on the controller (home screen logo only).
•The screen will display a service message prompt.
•Press Yes. (Note: All alarm signals/outputs will be inhibited for fifteen (15) minutes.
•Proceed to test gas detectors.
•Upon completion –exit service mode by pressing the ‘Exit’ button on screen.

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STEP 2
Test Detector
Access to the interior of the detector, when carrying out any work, must be conducted by a competent person!
•Ensure you have the correct gas for the device type prior to application.
•Screw and seal the regulator/valve into the gas cylinder outlet.
•Once sealed, the regulator pressure gauge will indicate cylinder pressure.
•Offer up the applicator hose/cone to the lower vents.
•Alternatively, enclose the device and apply gas i.e. in an airtight bag or container.
•Open the valve/regulator to allow the gas to be delivered at a pre-set flow rate.
•Wait for the device to enter alarm status and energise configured outputs/relays.
•At this point…
•Remove applicator hose/ cone and turn the gas cylinder regulator/valve off.
•Wait for the device to return to normal.
•Reset the system.
•Record your test details. There is a provision for this in your control panel manual.
End.
Reset Service Message
Access to the interior of the detector, when carrying out any work, must be conducted by a competent person!
It is recommended to bump test detector(s) prior to resetting the service reminder message!
1. Carefully remove the detector cover to access the circuit board.
2. Short out the unmarked service header for ~5s and wait for a ‘beep’.
3. The service message on screen will reset.
4. Carefully replace the back cover.
End of Operational Life (EOL)
The EOL is approximate from the first five (5) hours of continuous power!
The EOL will depend on the type of gas your detector is targeting and may vary depending on its application and
environmental conditions such as the frequency of exposure to the target gas, poisons or inhibitors!
The typical life of a gas detector depends on its application and intended target gas, in addition the
operational life can be prolonged if the system and equipment is installed and maintained in
accordance the instructions stated within this manual.
At the end of its predicted operational life –the detector will display an ‘End of Life’ screen. This message indicates
that the detector has reached its expected operational lifecycle and no gas levels are displayed.
You must contact your supplier immediately for replacement.

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Specification
General
Product:
GDPX+: Gas Detection Control Panel
Use:
Indoor, Safe Areas (not to be used in potentially explosive atmospheres)
Indicators (4.3” Touch Screen)
Main Zone Status. ID. Gas Type. Concentration Level. Measured Value. End of Life. Fault. Service.
Screen Brightness
Adjustable 0-100%
Mounting
Wall Mounting
Electrical
Max. Power Consumption
48W Max (Full Load)
Power Voltage Input Range
100-120vac
Gas Valve Output Range
100-120vac
Electrical Contactor Output Range
100-120vac
I/Os
3x 24vdc Outputs (Detector / Strobe or Sounder / Permenant)
5x Open/Close Switches (EM Stop / Heat Sensor / Fire Panel / 2x Selectable)
BMS Terminal
Volt Free (Normally Closed / Common / Normally Open) 3A Max
Communication
RS485 MODBUS RTU
Relay(s)
2x 120vac 10A (Latching Switch)
Terminal Wire ratings
Copper 18AWG (0.75mm2) Min. 25 x screw terminals.
Fuse
3.15A
Internet (Unavailable)
Ethernet (RJ45)
Construction
Dimensions (H x W x D)
180 x 255 x 77 mm/ 7.08 x 10.03 x 3”
Unit Weight (Approx.)
1.1kg / 38.8oz
Housing Material
Polylac - PA765
Environmental
Ingress Protection
IP65 (Pre-installation)
Storage Conditions
Dry. Cool. Flat
Operating Conditions
-10 ~ 50°C / 14 ~ 122°F 30 ~ 80% rf
Compliance
CE / UKCA
EN 61326-1 / BS EN IEC 61010-1

Installation & Operation Manual Merlin GDPX+
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Installation Details
Please pass this manual to the system owner / user.
Date of Installation:
Installation Location:
Organisation:
Stamp/Signature of the installer:
We recommend all Merlin gas detection equipment be commissioned by a competent/trained engineer to ensure
correct installation and operation. The Merlin range of gas detectors are calibrated when manufactured, however, we
strongly recommend the detectors response and alarm signals are tested and validated once installed. This will
ensure the equipment performs as intended and is free from any unforeseen damage caused by transit/installation.
Every effort is made to ensure the accuracy of this document; however, CGS can assume no responsibility for any
errors or omissions in this document or their consequences. CGS would greatly appreciate being informed of any
errors or omissions that may be found in the content of this document. For information not covered in this document,
or if there is a requirement to send comments/corrections, please contact CGS using the contact details given below.
Canadian Gas Safety
[email protected]om
Telephone: [phone]