If you’ve just arrived at work and your fume cupboard fan isn’t switching on, it could mean a few things. We’ve created a fault finding list below which you can use to determine the problem with your extraction system.
If you need assistance getting your system up and running, don’t hesitate to get in touch with the team today.
1. Power Supply Checks
- Verify Power Availability:
- Check that the main power supply to the fan’s motor is switched on and that there is no power outage or tripped breaker upstream.
- Inspect circuit breakers, fuses, and any protective devices for signs of tripping or blown fuses.
- Examine Motor Disconnect/Isolation Switch:
- Make sure the motor isolation switch is in the “ON” or “CLOSED” position and functioning properly.
- If equipped with a local disconnect, confirm it is switched to “ON.”
2. Motor and Starter Components
- Motor Overload or Thermal Protection:
- Check if the motor overload relay has tripped. Reset if necessary, and investigate the cause (e.g., overcurrent, overheating).
- Inspect any thermal switches or thermistors inside the motor (if applicable).
- Contactor or Starter Inspection:
- Listen for audible clicks or buzzing when starting. No sound could indicate a faulty coil or no control signal.
- Visually inspect contactor points for burn marks or excessive wear.
- Control Circuit and Safety Interlocks (where installed):
- Verify that all safety interlocks (e.g., emergency stops, door switches, pressure switches) are closed or in the correct position.
- Check start/stop buttons or switches for continuity if they are suspected to be faulty.
3. Fan Environment and Ductwork
- Dampers and Vents:
- Verify any inlet/outlet dampers are in the correct position (open) and not stuck.
- Check that ducting or filters are not completely blocked.
4. Resetting and Trial Run
- Reset Overloads and Protective Devices:
- After diagnosing the issue (e.g., a tripped overload), reset the device.
- Confirm the cause of the trip is resolved before re-energizing.
- Test Run:
- Reapply power and perform a short test run to verify correct operation.
- Monitor the motor current, vibration, and any unusual noises.
5. Maintenance Records and Preventive Measures
- Document Findings:
- Log the issue, cause, and corrective actions.
- Keep track of voltage, current, and other measurements during normal operation.
- Schedule Regular Maintenance:
- Regularly check belts, bearings, and motor windings.
- Clean and inspect impellers and ductwork on a routine basis to prevent unexpected failures.
Safety Reminder
- Always follow lockout/tagout procedures before working on electrical or mechanical systems.
- When in doubt or if you detect any motor damage or complex control-circuit issues, consult with a qualified technician or electrician.
This checklist should help you identify common causes for a centrifugal fan not switching on and guide you through a logical approach to troubleshooting.
