Omniguard 760 series, Инструкция по установке и эксплуатации, Страница: 11 / 16

11 ©Firefly AB (Oktober 2016)
Maintenance and troubleshooting
Note:
It is recommended that when cleaning or servicing the Flame
Detector, that any suppression or alarm systems be disabled .
Omniguard® 760 Series Flame Detector is designed for years of
trouble-free operation with minimal attention . Periodic cleaning of
the optical surfaces is essential, however, for maintaining reliable fire
protection . The frequency of required cleaning will be determined
by the environmental conditions in and around the installation . The
detectors should be regularly inspected for a build-up of dust or other
contaminants on the optical surfaces .
The detection specifications presented in this manual are predicated
on performance with clean sensor windows . Contaminants such as
dust, oil and paint will reduce sensitivity . Severe contamination on the
light guides or sensor windows will cause a failure of the self-test . A
detector that fails self-test due to dirty optical surfaces may be capable
of detecting fire, but its effectiveness will be limited to 30 to 50% of its
specified range .
Cleaning Procedure:
Locate the following optical surfaces: (Figure 9)
1 . Fire IR Window
2 . Fire Light Guide End
3 . Reference IR Window
4 . Reference Light Guide End
Clean the optical surfaces with a cotton swab wetted with commercial
liquid glass cleaner, ammonia, methanol, or isopropyl alcohol .
Rinse with clean water and dry with lens quality cloth . Repeat with
methanol if needed to remove smudges .
Caution: Wiping with excessive force or inappropriate materials may
scratch the optical surfaces and impair performance .
Troubleshooting:
*WARNING* Do not attempt to repair a detector . Study these
troubleshooting guidelines and review the referenced sections of the
manual prior to performing maintenance on the fire detection system .
New Installations:
When the detectors are in operational mode, a green LED will be
visible for one second approximately every ten seconds . If any or
all the detectors fail to operate, check the system wiring and power
supply . Tight, reliable wiring connections are essential, as are low-
resistance connections from every detector housing to earth ground .
Measure the voltage between terminals 8 and 10 at the detector
locations to verify that the supply voltage is within range .
Note: Voltage at detectors installed farthest from power source will be
lower than the no-load supply voltage due to line losses . Maximum
load condition occurs during manual test .
The Omniguard® 760 Series Flame Detectors employ sensitive and
sophisticated electronic circuitry . Power line transients or excessive
power supply ripple may therefore cause erratic or intermittent
operation . DC-powered detectors function best with ripple-free
(less than 1 percent) supply voltage; power supply filtering may be
necessary to improve performance . In areas that are unprotected from
shielding and have the potential for conducted RFI/EMI directly into
the power lines, it is highly recommended to use a Corcom Filter P/N
15DCB6F or equivalent on the power lines .
Note:
For reliable operation, the instantaneous supply voltage at the
input to any detector must not fall below 20 Vdc or exceed 30 Vdc .
Failure To Alarm:
Upon detection of fire, the fire outputs will activate and the red LED,
visible through the LED window, will turn “ON” .
If during testing a detector fails to alarm, inspect the sensor windows
for cleanliness . Clean sensor windows are essential for effective
optical fire detection . Clean all the optical surfaces per the cleaning
procedures previously described and retest the detector .
Should the detector continue to be inoperative, check the supply
voltage and all associated wiring . Incorrect power supply voltage or
loose connections will cause marginal or intermittent performance .
Alarm Condition – No Fire Present:
A detector in alarm condition when no fire is present may be caused
by an inadvertent actuation of the manual test . The Series 760
Flame Detectors feature a manually initiated self-test feature of the
optical and electronic systems . If the light guides are continuously
illuminated, check the manual test wiring and the test switch for
broken, loose, or intermittent connections . Repair or tighten any faulty
connections . If the light guides are not illuminated, then contact your
Firefly AB representative .
Confidence Condition:
The Model 760 Flame Detectors are equipped with a fault relay to
annunciate a change in the operational status of the detector . When
power is applied to the detector, the fault relay will energize within 8
seconds under normal environmental conditions . A loss of power will
cause the relay to de-energize .
If the fault relay output fails to change state within 8 seconds after
power-up and the amber LED fails to illuminate, then there may be no
power reaching the detector’s electronic module . Check the supply
voltage, the condition of the fuse located at F1 on the PCB and the
wiring to terminals 8 and 10 . Also, inspect the wiring to the fault relay
terminals 6 and 7 and the jumper JP1 that sets the fault relay option .
Note:
Model 760 Flame Detectors are equipped with a 0 to 20 mA
option . A loss of power will result in a constant 0 mA output .
If the fault relay output continues to be inoperative, isolate the relay
contacts by disconnecting the external wiring to the fault relay
terminals . Connect an Ohmmeter across the fault relay terminals and
monitor for an actuation of the relay . Repair the external wiring if
necessary .
Fault Condition:
Note: During environmental conditions that cause a large thermal
transient such as moving a detector from inside a warm building to
outside in the cold, the detector will be inoperable until it stabilizes
to the new thermal condition . The fault relay will remain off and the
Amber LED will flash at a 2 Hz rate due to the exceedance until the
detector acclimates to the environment . This will be an indication of an
Exceedance Fault .
Model 760 Flame Detectors are equipped with a 0 to 20 mA output .
When the 0 to 20 mA option is not used, make sure that the 0 to 20
mA option is “OFF” on the USI . If the 0 to 20 mA option is “ON” and at
any time the driveline opens or the current sense is not at the proper
level, it will cause the activation of the fault outputs . Check the
wire terminal 15 and insure that a good signal ground is present at
terminal 10 or 11 . To insure that the 0 to 20 mA option causes the fault
(Fig 9) Optical Surfaces