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08/03/2018
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 4 detectors of different types.
Detector Alarm levels
Type
Pre-Alarm
High Alarm
CO:
80ppm
100ppm
CO2:
1800ppm
2800ppm
Pre-alarm will display a warning message and tone (3beeps) every 10mins.
High-alarm will display a warning message, tone every one second and isolate the gas valve after 60seconds.
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.
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) and then “learnt” using
button
18 (see page 3)
Status LED
SafeAir CM
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.)
Pressure sender unit, remote emergency stops, 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.
