Medem AGDS-4 User manual

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AGDS-4
Installation Instructions
The AGDS-4 is a four channel gas detection system designed for use in boiler houses. Up to four low voltage
detectors can be connected for the detection of natural gas, LPG or carbon monoxide.
In the event of a high alarm from one of the detectors, the system will isolate a connected control valve. Low
alarm indication is also given
It is designed for use primarily in boiler house.
AGDS-4 features
• Gas Detection . (Up to four detectors)
• Natural gas, LPG and carbon monoxide
• Remote emergency stop
• BMS relay (high alarm status)
• 5 year warranty
Before commencing installation please familiarise yourself to the equipment by reading the comprehensive
installation instructions. If in doubt then please call 01 4614300.
It is a statutory requirement that this safety system is installed and commissioned
to the satisfaction of the manufacturer.
A commissioning certificate must be issued to the end user along with instructions for the operation of the
equipment.
As the Manufacturer Medem UK or approved Medem commissioning engineer should commission this
safety system whereupon a commissioning report will be forwarded to the installing agent who should
provide a copy to the end user.

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System description
AGDS-4
The AGDS-4 is a gas detection system designed to monitor the atmosphere for target gases. The system comprises of a mains
powered panel capable of operating up to four sensors, either combustible or Carbon Monoxide gas or a mixture of both. The
sensors are pre-calibrated by Medem (UK) Ltd such that they only require to be connected to the panel and functionally tested.
In the event of a high alarm from one of the sensors the system will isolate the gas supply by closing a connected electric control
valve. Emergency stop buttons and Thermal Links can be fitted and a fire alarm can close the gas valve when connected to the
panel.
Control Panel
Detector LED’s
No Detector Off
Detector Powered Green (flashing during warm up)
Low Alarm Flashing red (every second)
High Alarm Flashing red (every 1/2 second)
High Alarm & Gas isolated Permanent Red
Sensor Alert Yellow
Low Volta e Gas Detectors
Combustible detectors are pre calibrated at 5% LEL (Pre alarm) and 10% LEL for the High alarm.
Carbon Monoxide detectors are pre calibrated at 80ppm (pre alarm) and 100ppm for high alarm.
Each detector has a rotary address selector switch (0-F) you must use address’s 1-4 only. Once connected and addressed you are
required to press the “learn Det’s” button (12). Once pressed the corresponding detector LED’s on the main panel will light green.
Each sensor unit has an LED which shows green when power is applied.
Note: There is a warm up period after initial power up of approximately 90 seconds. During this time the green LED will flash once
per second and the output signal will be inhibited. This is to prevent spurious alarms. After the warm up period and on application
of gas, the red LED will light when a high gas alarm level is reached.
Sensor Alert state (yellow LED): indicates that a previously learnt detector is no longer being recognised, normally due to a change to
the detectors address or an issue with the wiring.
When first powered or after a loss of power press and hold the reset button for 2 seconds to start the system and
open the as valve.
LED indications:
Power On Green
Gas On Red
Em Stop Yellow
Panel Buttons:
Mute button
Reset button
Press and hold reset button (2’s) when power is first applied to
enable gas.

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Main features
AGDS-4
Power at 230
volts from a
3amp fused spur
1. Live & Neutral 230 volts supply from 3amp switched fuse spur
2. 230 volts out to gas solenoid valve (5amp relay)
3. Earth connection terminals
4. High Alarm BMS relay (potential free contact, mains rated, max load 5amp)
5. Remote emergency stop buttons SELV, multiple buttons connect in series (requires a N/C circuit)
6. Power connections for detectors, Methane, LPG, CO.
7. Comms connections for detectors, Methane, LPG, CO.
8. Aux Relay, (potential free contact, SELV Only) - see 11 for settings (non-latching)
9. Jumper link to disable audible alarm sounder.
10. High alarm time delay function - Controls the length of time between a High alarm and the closing of the gas valve
11. Aux Rly Switch - Setting controls the Aux Relay switching conditions
12. Learn Detectors - Press after connecting & addressing Medem gas sensors (detector address’s 1 - 4 only)
13. Front Panel button connection - Mute
14. Front Panel button connection - Reset
15. Front Panel button connection - Emergency Stop
Aux1 Aux2 State
OFF OFF = Low Alarm
ON OFF = Detector Alert
OFF ON = Em-Stop
ON ON = Gas On
Connections to panel: marked on board

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Wiring information
AGDS-4
Basic connections
230v Supply
3Amp Fused Spur
EM Stop Buttons,
Thermal links
(Normally closed)
For multiple, connect in
series.
Gas Solenoid
Earth Connections not shown
Mains Rated
Potential free contact,
Max load 5amp’s
(latching relay)
Addressable Gas
detector
Set to address 1,2,3 or 4
And then press Learn (12)
SELV (max 48v),
Potential free contact,
Max load 5amp’s
(non-latching relay)
Wire multiple detectors in
parallel
All current wiring regulations must be followed with reference to running low and mains voltage cables together.
The maximum cable length between a detector and the control panel should not exceed 100 metres, if the distance between
the main panel and the detectors is greater than 20metres a 1mm screened cable must be used on the +VE, 0v terminals
Gas detectors, require a four core screened Belden type security cable or 600v rated BMS cable (max cable length of
100meters.)
Remote emergency stops and thermal links require a two core screened cable.
Warranty will be void if Fire Protection Cable or cable over 1mm dia. is used on the SELV side.

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Remote stop buttons
AGDS-4
To EM Stop connections in the
panel
Use terminals TB2 A & C Use terminals TB2 A & C
Remote stop buttons can be connected to the panel terminal
marked as “EM STOP” (number 6 ).
The remote buttons must be wired as shown in order to provide a
“closed contact” for the control panel.
If thermal links are to be installed these should be wired
in series with the EM stop buttons
To EM Stop connections in the
panel
Indicator bar shows when
pressed
Normal EM-Stop Activated
Multiple Stop Buttons
Sin le Stop Buttons
Resettin (indicator bar)
The stop buttons supplied by Medem are of a “Push Glass, key resettable” style, when activated a yellow indicator bar will
show and the unit will require resetting using the key provided.
Multiple stop buttons are wired in series.
If thermal links are to be installed these too should
be wired in series with the EM stop buttons
Use terminal TB2 A & C

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Gas Detection
Gas Detectors
IMPORTANT - Gas Detectors should not be installed until all building, construction or painting work etc.. Is completed, as these
works can effect the sensitivity and longevity of the detectors.
Ensure that the protective cover labels (RED) are removed only
after the completion of all building work and the system has
been commissioned by the Medem engineer.
The labels are required to be removed for the detectors to
operate, but removal before the completion of works risks
contaminating the sensor element.
The system is capable of operating a mix of up to 16 detectors (additional power pack may be required) of different types.
The detector types are:
•Carbon Monoxide.
•Combustible gases (Methane, Propane).
Detector location will vary dependant on the individual characteristics of the target gas that is being monitored for. See the gas
detectors own instructions for more guidance.
AGDS-4 Detector Information
+VE supply & Comm’s
From either the main panel
Address Selector
Each detector must be set to its own
address either 1,2, 3 or 4.
And then “leant” using button (12)
Connection and addressin
Status LED
All current wiring regulations must be followed with reference to running low and mains voltage cables together.
The maximum cable length between a detector and the control panel should not exceed 100 metres, if the distance between
the main panel and the detectors is greater than 20metres a 1mm screened cable must be used on the +VE, 0v terminals
Gas detectors, require a four core screened Belden type security cable or 600v rated BMS cable (max cable length of
100meters.)
Remote emergency stops and thermal links require a two core screened cable.
Warranty will be void if Fire Protection Cable or cable over 1mm dia. is used on the SELV side.

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Detector Information
Detector location will vary dependant on the individual characteristics of the target gas that is being monitored for.
The descriptions below describe the position for each detector after considering these characteristics.
For proper function care must be taken not to site a detector in a “dead space” or in the flow of any ventilation.
Natural Gas/Methane
Natural gas detectors should be mounted at high level on a wall approximately 150mm from the ceiling height and avoiding
corners and potential dead air areas.
Natural gas detectors should not be mounted below the height of the top of a doorway for example. This is because as the gas
is slightly lighter than air it will rise filling the room from the ceiling down and will spill through the top of a door opening into the
next room. If the detectors are mounted below this height then it will take longer the gas to reach the detector.
LPG /Propane
LPG gas is heavier than air so detectors need to be mounted at low level 100mm from the floor, consideration should be given
to any potential mopping or wet floor height.
Carbon Monoxide
Carbon Monoxide is similarly weighted to air so detectors should be mounted between 1 to 2 meters from the floor.
Carbon Dioxide
Carbon Dioxide detectors should be installed so they monitor the general level of CO2 within the area. They should be mounted
above standing head height and between 1m and 3m from the potential source. Care should be taken so they are not located
close to the edge of a canopy or in direct flow of the supply or extract ventilation.
For additional information or guidance on site specific requirements please don’t hesitate to contact us.
Each detector has its own Bi-Colour LED which is used to indicate the status of that detector.
Not Lit: No power/comm’s. These a four wire units and all connections are required, check the polarity of both the
power and the comm’s (MA/MB) terminals are correct. Check the detector is address to the correct channel
and the channel has been enabled using switch (12)
Flashing Green: Detector is warming up, the detectors will flash green on power up for 90 seconds while the sensor
elements stabilize. The system will ignore any detectors while flashing.
Solid Green: Detector is powered and active.
Flashing Red: Low level alarm. All detectors have both a low and high level alarm, low level alarms serve as a warning
that an unsafe condition maybe building and gives chance to intervene before loss of gas service.
Solid Red High level alarm. An unsafe level of the target gas have been reached and the system will isolate the
gas supply. The cause of the alarm will require identifying and resolving before the gas supply can be re-
established.
After installation a simple bump test can be performed by using an appropriate level test gas in order to check operation. Full
testing and calibration checking takes place during a Medem commissioning.
AGDS-4
Detector Location information
Detector Indications

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Warranty
AGDS-4
Medem (UK) Limited
Project House
19 Dallimore Road
Manchester
M23 9NX
Tel: [phone]
Fax: [phone]
Web: www.medem.co.uk
E-mail: [e-mail]
Medem UK Warranty
Terms & Conditions
1. The warranty is a parts warranty and Medem UK Ltd will not cover or accept any labour or
other expenses that may be incurred in the process of changing faulty product.
2. All panels and sender units are covered by a five year warranty.
3. Gas detector units and other remote detectors carry a two year warranty. Installation of the
detectors should not be undertaken until all building and construction work is completed.
4. Gas solenoid valves carry the original manufacturers warranty, though as the supplier
Medem UK will exchange faulty valves for return to the manufacturer.
5. Where a warranty claim is made then, where appropriate, a written order to attend site
must be provided to Medem UK A cost for labour and travel to site will be prepared as a
quote. The cost must be included in the order.
6. Where it is found that the installation and/or the quality of workmanship has contributed to
or wholly caused the failure of the product then we reserve the right to charge the whole or
a proportion of the cost of the faulty item.

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It is essential that the installation is carried out in the order given
below to ensure the correct operation of the system.
First read the system description sheet before following the
instructions below
1. Connect the Control valve twin & earth to the marked terminals.
2. Connect BMS, beacons, sounders etc to the relay outputs.
3. Connect any additional EM stop buttons and thermal links in series to the terminals marked “EM STOP”.
4. Each detector has a blue rotary switch and each switch should be set to a different number or letter starting with
“1”. Then connect the gas detectors to terminals marked “detectors” on the panel. Detectors can be wired “Daisy
chain”.
5. Connect the 3 amp fused spur 240 volt supply to marked terminals.
6. When first powered press the reset button to start the system and open the gas valve.
7. Once power is connected to the panel the detectors will flash the green LED’s for 90 seconds after which the LED’s
will be on continuously.
8. Press the “learn field button” this is on the main circuit board on the right hand side, just over half way up the
board. Pressing this once allows the panel to learn how many and which type of detectors are fitted.
Checklist
AGDS-4
Please do not hesitate to call for advice on the
following number:
01 4614300 office hours
For more information about any Medem product please contact Modern Plant.
Our team of experts are on call to answer all your questions and provide you
with advice to ensure your project is successful.
Web: www.mpgassafetysystems.ie | Email: [email protected] | Tel: [phone]
Notes.
It is recommended that all systems are commissioned after installation by Medem UK.