GAS Gasmaster, Installation, Operation And Maintenance Manual

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2.1 Before installation
Before carrying out any installation work, ensure that
local regulations and site procedures are followed.
Further advice is available from Gas Alarm Systems if
required.
Gasmaster is intended for use in non hazardous areas.
Gas and fire detectors may be mounted in potentially
flammable atmospheres using appropriate barrier
devices where necessary. Check the equipment to be
installed is suitable for the area classification. Please
refer to instrument installation manuals for information
on location.
Gas Alarm Systems recommends the installation of
Gasmaster be carried out by people with experience of
installing electrical equipment in potentially hazardous
areas.
2.2 General
This section describes how to get started with a
Gasmaster 4 or Gasmaster 1 system that has been pre-
configured for the detectors supplied. Figures 2.1, 2.2
and 2.5 show the internal structure of Gasmaster.
See the Specification and Inspection Certificate
provided with your system for full details of its
configuration.
Figure 2.1 shows the internal arrangement of a
Gasmaster system. The front cover
➀
is removed
by unscrewing the four screws
➁
and carefully
disconnecting the two-pole sounder connector
from the display PCB
➂
. The front cover can either
be supported by the case using one of the retaining
screws, or removed completely and placed in a safe
location. Two separate chassis support the display PCB
and batteries which supports the display PCB
➂
and
batteries
➃
. The terminal PCB
➆
contains the input
modules, and all of the input and output terminals. The
display PCB
➂
is connected to the terminal PCB
➆
via
a 50-way ribbon connector, and is hinged on the left
side so that it can be moved to provide access to the
detector input terminals. Most terminals are accessible
once the display PCB is moved and the batteries are
removed. If necessary the two chassis can be removed
for easier terminal access.
In order to remove the display chassis, the display PCB
ribbon connector must first be carefully unplugged.
Care should be taken when re-fitting the display PCB so
as not to damage the connector or ribbon cable.
Six punched cable gland knock-outs are provided
on the top and bottom of the enclosure. The knock-
outs are suitable for M20, 1/2”NPT or PG13.5 cable
glands. To remove Knock-outs,tap around the edge
of the recessed flange using a small hammer and a
screwdriver. The knocks outs should then come away
from the enclosure
Knock-outs should be removed prior to mounting
Gasmaster and great care must be taken to avoid
damaging internal components.
Power supply
Gasmaster comes fitted with an auto-ranging power
supply suitable for 100-240 V ac 50-60 Hz operation.
This provides a nominal 24 V dc supply with a
maximum power of 60 W. Alternatively Gasmaster
can be powered from an external 24 V dc supply, a
maximum 60 W supply is required. Gasmaster must
never be connected to ac and dc supplies at the same
time.
2. Installation