Atest Gaz Alpa MOD LED8, Руководство пользователя

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Liquid gas (LPG)
These gas detectors should be placed acc. to similar principles as methane gas detectors, taking into
account the fact that both propane and butane are heavier than air and will accumulate close to the floor.
This is why the gas detectors should be placed no higher than about 20 – 40 cm from the floor level.
Carbon monoxide (CO)
Due to similar density to the density of air, the gas detectors should be installed approx. 170 – 200 cm
above ground level, especially in car diagnostic stations where heated exhaust gases tend to rise up.
Hydrogen sulphide (H
2
S)
Hydrogen sulphide is heavier than air and will therefore lie on the floor. It is recommended to install the gas
detectors at approx. 30 cm from the floor level. They should point measuring side down. In such facilities as
waste water treatment plants it is recommended to install gas detectors in splash-proof housings, securing
the gas detectors from direct contact with water.
When installing the Gas Detector, work according to indications of a technician or a fire
protection surveyor.
6.2.3 Connecting gas detectors to the control unit
The supply line should be designed in such a way that at the lowest expected supply voltage, the value of
the voltage detected by gas detectors terminals does not drop below the permissible value.
The maximum number of Alpa EcoWent XT and Alpa EcoDet XT Gas Detectors in open and closed loop is
described in Appendix [3] and [4], while information about sample connection cables for the gas sensors
with an output at 4 – 20 mA can be found in Appendix [5].
6.2.4 Connecting an external acoustic device
These connections should be carried with a cable with a cross-section compatible with the data in table 6
– see Appendix [5]. When using cables with the smallest diameter it should be remembered that they have
relatively low mechanical strength. In justified cases, it is recommended to use PVC trays. However, do not
use cables which are too thick because of a limited cross-section of chokes in the housing Cables too large
in diameter may not pass through them.
6.3 Start-up
The control unit module must be supplied in accordance with parameters set out in table 6:
Voltage supply parameters for the control unit must be also compatible with other system
elements (gas detectors and signallers).
The control unit module has 4 relays with dry contacts that can be used to control the automation, traffic or
ventilation systems (e. g. two-speed fan). Installing the system, you should be aware of the following things:
for safety reasons, the device has no power switch
It is, therefore, necessary to envisage a power circuit breaker on the power line for the device.
This switch should be placed in a separate switch-box and should protect both power lines – see
Appendix [5],
relay outputs are not protected against overload. Shorting the outputs can cause irreparable
damage to the control unit module. Therefore, external protection circuits should be provided,
protecting these relays according to the best practices when working with this type of installation,
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User Manual: POD-006-ENG R03