CAT Preventive Maintenance Procedures 3 — Questions and Answers
Question 1: When inspecting a duct smoke detector during PM, what physical check is essential before testing?
- Verify conduit size matches specifications
- Confirm sampling tubes are clear, properly oriented, and undamaged (Correct answer)
- Check that the duct is at least 12 inches wide
- Measure duct air velocity with an anemometer
Correct answer: Confirm sampling tubes are clear, properly oriented, and undamaged
Blocked or misaligned sampling tubes prevent smoke-laden air from reaching the sensing chamber, making the detector non-functional.
Question 2: A technician is testing a pull station and finds the cover glass is cracked. What is the appropriate PM response?
- Apply clear tape to secure the glass temporarily
- Replace the pull station or cover glass before leaving the site (Correct answer)
- Document and defer replacement to the next annual visit
- Disable the device and notify the monitoring station
Correct answer: Replace the pull station or cover glass before leaving the site
A cracked cover compromises tamper protection and weatherproofing; the component must be replaced during the same visit.
Question 3: During PM on a burglar alarm system, the technician measures 12.8V on a 12V sealed lead-acid battery at float charge. This indicates:
- The battery is overcharged and must be replaced
- Normal float voltage for a fully charged 12V SLA battery (Correct answer)
- The charger circuit has failed
- The battery is deeply discharged
Correct answer: Normal float voltage for a fully charged 12V SLA battery
A float voltage of approximately 13.5–13.8V is typical at the charger; 12.8V open-circuit indicates a fully charged SLA battery.
Question 4: Which of the following is the correct procedure when temporarily disabling a zone during maintenance to prevent false dispatches?
- Disconnect the zone wire at the panel
- Notify the monitoring station and place the zone on test mode before beginning work (Correct answer)
- Remove the detector from its base without notification
- Set the panel to walk-test mode only
Correct answer: Notify the monitoring station and place the zone on test mode before beginning work
Notifying the central station and placing the zone on test prevents unnecessary emergency dispatches during maintenance activity.
Question 5: What is the purpose of exercising electromechanical relays during a PM inspection?
- To reset the relay's memory register
- To prevent contact oxidation and ensure reliable switching (Correct answer)
- To recalibrate timing circuits
- To increase relay coil resistance
Correct answer: To prevent contact oxidation and ensure reliable switching
Cycling relays during PM clears oxidation from contacts that builds up from inactivity, ensuring dependable operation during emergencies.
Question 6: A carbon monoxide detector installed in a commercial building fails to respond to a CO span gas test during PM. What should the technician do?
- Clean the sensing element with isopropyl alcohol and retest
- Replace the detector immediately (Correct answer)
- Increase the gas concentration and retest three times
- Record the failure and schedule replacement within 90 days
Correct answer: Replace the detector immediately
A CO detector that fails functional testing must be replaced immediately because electrochemical sensing cells cannot be field-recalibrated.
Question 7: When conducting PM on a monitored alarm system, which step verifies the communication path to the central station is functional?
- Checking panel LED indicators only
- Performing a full communications test transmission and receiving confirmation from the central station (Correct answer)
- Reviewing the panel's event log for the past 30 days
- Measuring DC voltage on the phone line terminals
Correct answer: Performing a full communications test transmission and receiving confirmation from the central station
A confirmed test transmission from the central station is the only reliable verification that the entire communication path is operational.
CAT Preventive Maintenance Procedures 3
When inspecting a duct smoke detector during PM, what physical check is essential before testing?