background image

08/03/2018 

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. 

 

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. 

Note

The detectors will still require correctly addressing (using the address 

 

 

 

selector pot) and learning by the system using button  

16 (see page 3)

 

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. 

    Detector Location 

    Detector Indications 

SafeAir CM 

Summary of Contents for SafeAir CM

Page 1: ... 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 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 At the point of our commissioni...

Page 2: ... CO2 Carbon Dioxide The system comprises of a mains powered panel capable of operating up to four sensors and internal two channel current monitor for interlocking the mechanical ventilation with a monitoring range of 30 mAmps to 24 Amps The ventilation can also be interlocked by mechanical air flow switches DP if required Control Panel The front of the panel has the following controls and indicat...

Page 3: ... B interlock for PD switches 12 Fan A current monitor CT connection 13 Fan B current monitor CT connection 14 Fill prove time for gas pressure proving AUX relay settings see No4 15 Set Fan A to use either PD switch No10 or Current Monitor CT No12 16 Lift valve button opens the gas valve only whilst the button is continuously pressed for commissioning purposes 17 Display gas pressures on the LCD sc...

Page 4: ...y dependant on the individual characteristics of the target gas that is being monitored for See the gas detectors own instructions for more guidance Detector Information Connection and addressing VE supply Comm s From either the main panel or an extender Detectors are wired in parallel and can be connected to one another daisy chain Address Selector Each detector must be set to its own address 1 4...

Page 5: ...nd 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 ...

Page 6: ...is will change the minimum trip current setting from the default 35mA to be that being used by the fans at your set speed Pressing button 19 Fan comm alone will display the new minimum trip current value If the fan load drops below that level for more than 10 seconds the system will give an alert and isolate the gas supply There is a 20 allowance for fluctuations in fan load due to temperature etc...

Page 7: ...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 Single Stop Buttons Resetting 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 bu...

Page 8: ...em UK will exchange faulty valves for return to the manufacturer 5 Where a Medem UK engineer or another company appointed by Medem UK commission and installed system then that system will carry a ten year warranty This applies to the main panel and the sender unit At the time of commissioning a security label with a serial number will be attached to the main panel box photographs and a comprehensi...

Page 9: ...e system will isolate the gas and report fans not running Check that the fans are not only switched on but actually running and moving air Gas Off Reset Em Stops Switch On Off The system has an panel mounted emergency stop and connection inside for remote buttons First check the panel button once pressed some require resetting by twisting and releasing Clear the message by turning the main system ...

Reviews: