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ADT490 TroubleShootingDevice Failures
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Introduction
‣Many problems are external to FAS‣Many are device problems
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Detection Circuit - Short
‣ 0 V across circuit terminals‣ Increase in current or decrease in voltage -> Alarm
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Detection Circuit - Short
‣ Smoke Detector circuits have more current to operate the Smoke Detectors
‣ Smoke Detectors must be compatible with FACP ‣ No difference to Fire Alarm Control Panel:
‣ Short through Device -> Alarm‣ Short between devices -> False Alarm
‣ Maximum current through current limiting resistors
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Detector Compatibility
‣ Sufficiently filtered‣ Enough current to latch the circuit‣ Below the foldback level
‣ circuit shut down ‣ device reset
‣ Tested to all FACP operating voltages‣ Costly Test
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Wire to Wire Short
‣ False Alarm - determine after dvices have been eliminated
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Wire to Wire Short
‣ Supervisory latches - until panel reset
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Manual Station Operation
‣ mechanically operated electrical switch‣ spring loaded push button or toggle‣ second is key switch‣ must be connected to circuit‣ increase the current
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Manual Station - No Operation
‣ Improper screw connect - found during Tests‣ wire twisted together under one screw‣ comes loose over time
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Connections - Proper & Improper
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Open Identified
‣ Station tested but does not go into alarm
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Open Identified
‣ Wire insulation under screw - due to haste
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Device Not Connected
‣ Make connections later - never done‣ Found during monthly or Annual test
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Wire Break
‣ When cut - scored to much -> wiggles and breaks
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Types of Manual Stations
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Station Problems
‣ Switch out of adjustment‣ self-wiping switch may grime up in dirty spaces‣ too much current through switch may damage
contact - check station specifications‣ bridge contacts to test - if alarm -> replace
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Station Problems
‣ corrosion on soldered lugs - check for dull cold solder
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Stations
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Alarm Operation
‣ First check the Stations‣ Fire Department to find cause of alarm‣ Reset station after advised by FD‣ See next slide -> same voltage and current
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Any Difference?
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Manual Station Checklist (p. 15)
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Correct Connections
‣ Wire fully engaged?
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Heat Detectors
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Smoke Detectors
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Smoke Detectors - Damaged
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Fire Detector Checklist (p. 20)
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Sprinkler Flow Devices
‣ Direction?‣ Vane or Pressure‣ Pneumatic delay or retard up to 55 seconds‣ Tamper connection -> should cause Trouble‣ locating problem is easier - only one device‣ may still require Boolean search
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Sprinkler Flow Devices
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Flow Switch Checklist (p. 22)
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Supervisory Devices (p. 24)
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Polarized Bells
‣ Contact can be carbonated - 12 to 150 mA‣ Single stroke - on wrong circuit‣ striker alignment?
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Signal / Notification Circuits
‣ Signal circuit terminals - Alarm or Supervisory?‣ Bell connected in reverse‣ Circuit voltage 2 to 24 volts supervisory‣ Current limiting fuse or breaker
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Signal / Notification Circuits
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Signal / Notification Circuits
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Other Polarized devices
‣ Horns, Strobes, & Electronic Horns‣ Star Strobe - up to 1.25 A
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Unsupervised Aspects
‣ Placement - not interior components
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Polarized Signal Checklist (p. 28)
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Speakers
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Speaker Checklist (p. 30)
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Telephone Handsets
‣ low level signal -. 50 mV‣ Wiring often twisted & shielded‣ hook-switch controls the supervisory current
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Telephone Handsets
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Telephone Handsets Circuits
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Telephone Checklist (p. 32)
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General Fault Checklist (p. 33)
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Battery Faults
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Battery & Charger Checklist (p. 34)
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Power Supply Faults
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Power Supply Checklist (p. 35)
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EndofPresentation
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