FACP FACP Troubleshooting & Diagnostics 1 — Questions and Answers
Question 1: A fire alarm control panel displays a 'ground fault' trouble condition. What is the most likely cause?
- A wire in the system is contacting a grounded surface (Correct answer)
- The panel battery is low
- A detector head is dirty
- The AC power supply has failed
Correct answer: A wire in the system is contacting a grounded surface
A ground fault trouble indicates that a conductor in the wiring circuit is making unintended contact with a grounded metal conduit or enclosure.
Question 2: Which tool is most useful for locating a wire-to-wire short circuit in an SLC loop?
- Multimeter set to resistance (ohms) (Correct answer)
- Clamp meter
- Oscilloscope
- Voltage tester
Correct answer: Multimeter set to resistance (ohms)
A multimeter set to resistance mode measures continuity and can pinpoint a short by identifying near-zero resistance between two conductors.
Question 3: An initiating device circuit (IDC) shows an 'open' trouble. What does this indicate?
- A break in the wiring continuity of the circuit (Correct answer)
- Too many devices are connected
- A detector is in alarm
- The panel software needs an update
Correct answer: A break in the wiring continuity of the circuit
An open trouble on an IDC means the supervisory current path has been interrupted, indicating a wire break or disconnected device.
Question 4: After replacing a smoke detector, the FACP still shows a trouble for that address. What is the FIRST diagnostic step?
- Verify the replacement detector is fully seated in its base (Correct answer)
- Reset the entire panel
- Replace the entire SLC card
- Check the battery backup level
Correct answer: Verify the replacement detector is fully seated in its base
A detector that is not fully seated will not make proper electrical contact with its base, causing persistent trouble conditions.
Question 5: A notification appliance circuit (NAC) shows a 'short' trouble. Which condition would cause this?
- Positive and negative conductors are touching each other (Correct answer)
- The end-of-line resistor is missing
- A horn/strobe has burned out
- The panel output voltage is too high
Correct answer: Positive and negative conductors are touching each other
A short on a NAC occurs when the positive and negative circuit conductors make direct contact, bypassing the load and circuit supervision.
Question 6: The FACP event log shows repeated 'detector dirty' warnings for one address. What is the appropriate corrective action?
- Clean or replace the smoke detector at that address (Correct answer)
- Adjust the sensitivity threshold to maximum
- Disable the detector point
- Replace the entire loop card
Correct answer: Clean or replace the smoke detector at that address
Repeated dirty-detector warnings indicate the chamber's sensitivity has drifted due to contamination, requiring cleaning or replacement per NFPA 72.
FACP FACP Troubleshooting & Diagnostics 1
A fire alarm control panel displays a 'ground fault' trouble condition.
What is the most likely cause?