Clean a VESDA Low Airflow Fault by Checking Filters, Piping, and Airflow Path

A VESDA low airflow fault is typically caused by clogged filters, blocked sampling pipes, or airflow restrictions. Start by inspecting and replacing air filters, verifying pipe integrity for leaks/kinks, and ensuring the sampling holes are unobstructed. Reset the system after clearing obstructions to restore proper airflow.

Common Causes of Low Airflow Faults

  • Clogged or dirty filters - Reduce airflow into the detector.
  • Blocked or pinched sampling pipes - Restrict air movement.
  • Obstructed sampling holes - Dust, debris, or paint can seal inlet points.
  • Leaks in piping - Cause pressure drops and inconsistent airflow.
  • Fan or pump failure - Mechanical issues in aspirating components.
  • Incorrect pipe routing - Exceeds maximum length or has sharp bends.

Step-by-Step Cleaning & Troubleshooting Guide

  1. Power down the system - Disconnect power before maintenance.
  2. Inspect and replace filters -
    • Remove the filter housing and check for dust buildup.
    • Clean reusable filters with compressed air or replace disposable ones.
  3. Examine sampling pipes -
    • Trace pipes for kinks, cracks, or disconnections.
    • Use a pipe cleaner or compressed air to clear blockages.
  4. Verify sampling holes -
    • Ensure holes are unobstructed (no paint, dust, or tape).
    • Re-drill holes if sealed (follow manufacturer specs for size/spacing).
  5. Check for leaks -
    • Pressurize pipes with low-pressure air and listen for hissing.
    • Seal leaks with approved tape or replace damaged sections.
  6. Test airflow -
    • Reconnect power and monitor the detector's airflow readings.
    • Confirm values return to the normal range (typically 0.8-1.2 L/min per hole).
  7. Reset the system - Clear faults via the control panel or software.

Preventive Maintenance Schedule

Task Frequency Tools Needed Estimated Time
Inspect/replace filters Every 3-6 months Compressed air, replacement filters 10-20 minutes
Clean sampling pipes Every 6-12 months Pipe cleaner, vacuum, compressed air 30-60 minutes
Check sampling holes Annually Flashlight, drill (if resealing occurred) 15-30 minutes
Test airflow calibration Every 12 months Flow meter, manufacturer software 20-40 minutes

When to Call a Professional

  • Fault persists after cleaning all components.
  • Sampling pump or fan shows mechanical failure (unusual noises, no power).
  • Airflow readings remain below 50% of expected values.
  • Electrical errors (e.g., "Fan Fail" or "Pump Overload") appear on the display.

Additional Tips

  • Avoid over-tightening pipe fittings - Can crack plastic tubing.
  • Use only approved pipe materials - Some plastics degrade with UV exposure.
  • Document maintenance - Log dates, replacements, and airflow readings.
  • Follow manufacturer guidelines - Deviations may void warranties.