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