Quadnet Control Panel Engineering and Commissioning Manual
54
Intermittent and Recurring Faults
Smoke Sensor Failed – Signal High
Ensure that the correct device is being investigated by comparing its description with the
device address, and / or the serial number.
Ensure that the Optical Chamber is clean, if not then replace it with a new one and allow it
to re-calibrate. See the sections on Self Calibration and Replacing Contaminated Optical
Chambers for further details.
If the problem still exists consider changing the electronics module.
Note that the Sita ASD detector has the electronics module and chamber integrated into a
single one-piece housing. This unit should be replaced as a complete assembly if either the
chamber or electronics module require changing.
Device Faults
If the system detects a
device fault or fire activation
during initialisation, the initialisation
will not fail at that point. All devices will be operational (as long as no other faults exist).
However, the system can only ignore a certain amount of fire or fault data until initialisation
is complete, and beyond certain limits initialisation will fail and the various fault or fire
activations will be displayed.
In either case, the event generated should be dealt with before the loop is reinitialised.
Firstly, investigate and rectify any Fire activations which are displayed. These may vary
from Manual Call Points which have not been reset, to Multipoint detectors which are
contaminated.
Secondly, investigate and rectify any fault conditions which are displayed. These may vary
from ‘Input open circuit’, to a Multipoint detector with its optical chamber loose (legacy Sita
Multipoint only) indicating signal low.
Please note: A short circuit between cores with a value of between 3k and 300 ohm can
cause corruption of the data on the loop and although no Short Circuit fault is reported the
system integrity will be compromised.
The system may then be reinitialised and commissioned as required.
Device(s) Lost.
If no obvious causes are apparent then replace the device.
Please note: A short circuit between cores with a value of between 3k and 300 ohm can
cause corruption of the data on the loop and although no Short Circuit fault is reported the
system integrity will be compromised.
Loop Open Circuit
If random or recurrent Loop O/C faults are reported then check the entire system for the
following:
Loose connections
. Ensure all terminals are reasonably tight.
Broken Connectors.
If the terminal is over-tightened the main body of the
connector may become broken, causing an intermittent open circuit.
