06
NISM/STHA/06
DATE:
PAGE:
No:
ISSUE:
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36
ST-H-AS SENSORTEC
ANALOGUE-ADDRESSABLE
HEAT SENSOR
INSTRUCTION MANUAL
NOV 2006
Section 2 - SENSOR MODELS
The ST-H-AS heat sensor is supplied, as standard,
withthreeterminals.
The ST-H-AS has the facility to activate a remote LED
indicatororauxiliaryfunction,as standard.
TheterminalsontheST-H-ASsensorheadare
configuredasfollows:-
Terminal 3 = -VE 3 mA aux output
Terminal 1 = Sig + (+VE) positive in/out
Terminal 6 = S- (-VE) negative in/out
Section 3 - BASE MODELS
STB-4Base:having4terminals,forstandard
usewithST-P-ASsensorincludingtheauxiliary
outputfunction.
Section 4 - INSTALLATION
In normal use, the ST-H-AS heat sensor will be
installed at ceiling level. Pass the field wiring through
the cable hole in the centre and from the rear of the
base. Offer up and affix the base to the ceiling or
conduit fitting with screws via the base mounting
holes. Consider visibility and orientation of the sen-
sor'sintegralalarmLEDindicatorwhenmountingthe
base. Connect the field wiring to the base terminals,
as detailed on page 5 making sure the wiring does not
obstruct fitting of the sensor head. Fit the heat
sensor head by inserting it into the base and turning
clockwise until the notch in the sensor's rim aligns
with base locking screw.
Section 5 - MAINTENANCE AND
CLEANING
Maintenance&Servicing:
Generally, it should not be necessary to dismantle the
heat sensor since there is no internal chamber which
mayrequirecleaning. Theheatsensing element and
holder may be kept clean by gentle brushing with a
clean, dry, soft brush for dry deposits. For sticky
deposits, the brush may be moistened with a little
alcohol. If the plastic outer cover becomes dirty, this
may be removed and cleaned in the same manner as
described above for the outer covers of smoke
sensors. When replacing this cover, make sure that
the led indicator locates properly in the hole in the
outercoverbeforepushingthe outercoverhome,
otherwisetheledwillbecomedamaged.
Servicing of the system should be carried out in
accordance with the requirements of BS 5839 Part 1,
Fire Detection and Alarm Systems for Buildings: Code
of Practice for System Design, Installation and Servic-
ing.
Themaintenanceproceduresdescribedbelowshouldbe
conductedwiththefollowingfrequency:
Onemonthafterinstallation:- RoutineInspection
andevery3months
after.
Every6months:- OperationalTest
Every12months:- Functionalcleanand
Test
Allabovefrequenciesofmaintenancearedependenton
ambient conditions.
RoutineInspection
i) Ensurethe sensor head is secure and undamaged.
ii) Ensure the surface of the sensor’s outer cover is
clean. If there are deposits due to the presence of oil
vapour, dust etc, then the sensor should be cleaned in
accordancewiththecleaninginstructionsdetailedlater
in this manual. It may be advisable to ensure that such
cleaningisconductedregularlyinthefuture.
iii)Ensurenoequipmentwhichmaygeneratehigh
temperatures has been installed in the vicinity of the
sensor since the last routine inspection. If such equip-
ment has been installed, then you should notify the Fire
Safety Officer or other competant authority that it’s
presence may cause false alarms.
OperationalTest
The purpose of the Operational Test is to confirm the
sensor’scorrectoperationinresponsetoaheatcondi-
tion.
i) Take any necessary precautions at the control panel
to limit the sounding of the alarm sounders/bells and
anyfireservicesummoningdevice.
ii)Introduceheat using a heatgun/hairdryerwhichhas
been designed especially for testing heat sensors.
iii) After the heat sensor has given the alarm condition,
reset the sensor from the control panel. It may be
necessary to allow a short time to elapse before reset-
ting the sensor, to allow any residual heat from the test,
todisperse.
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