Fan Coil Unit (FCU) Maintenance Guide

tep-by-Step Checklist

Proper maintenance ensures efficiency, longevity, and air quality in FCU systems. Follow this comprehensive guide for residential, commercial, and industrial FCUs.

📌 Monthly Maintenance (Basic Checks)

1. 🔹 Filter Cleaning/Replacement
   • Remove, vacuum, or wash filters (if reusable).
   • Replace disposable filters every 1–3 months (or when dirty).
   • Neglecting filters reduces airflow by 30%+ and strains the fan motor.
2. 🔹 Inspect Airflow
   • Ensure vents are unobstructed (no furniture/curtains blocking).
   • Listen for unusual noises (indicating fan imbalance or debris).
3. 🔹 Check Drain Pan & Line
   • Remove sludge/algae buildup with a vinegar-water mix.
   • Ensure the drain line has a 1–2% slope to prevent clogging.

📌 Quarterly Maintenance (Intermediate Checks)

4. 🔹 Coil Cleaning
   • Use a soft brush or coil cleaner to remove dust/mold.
   • Dirty coils reduce heat transfer efficiency by 20–40%.
5. 🔹 Fan & Motor Inspection
   • Lubricate bearings (if not sealed).
   • Tighten loose fan blades to prevent vibration noise.
6. 🔹 Thermostat Calibration
   • Test temperature accuracy with a separate thermometer.
   • Replace batteries in wireless thermostats.

📌 Annual Maintenance (Professional Servicing)

7. 🔹 Water System Flushing
   • Drain and flush pipes to remove scale, rust, or air pockets.
   • Add corrosion inhibitors if needed (for closed-loop systems).
8. 🔹 Valve & Actuator Testing
   • Check 2-way/3-way valves for smooth operation.
   • Test actuators (if automated) for proper response.
9. 🔹 Electrical Safety Check
   • Inspect wiring for fraying or loose connections.
   • Verify grounding and circuit breaker ratings.
10. 🔹 Ductwork Inspection (If Applicable)

• Seal leaks with aluminum tape (not duct tape).
• Clean ducts if mold or dust buildup is visible.

⚠️ Common FCU Problems & Fixes

✅ Best Practices for Long-Term FCU Care

✔ Use High-Quality Filters – Pleated or HEPA for dust-sensitive areas.
✔ Install a Water Treatment System – Prevents scale/corrosion in pipes.
✔ Schedule Professional Inspections – Yearly for complex systems.
✔ Monitor Energy Usage – Spiking bills may indicate FCU inefficiency.

🔧 Tools Needed for DIY Maintenance

• Soft brush/vacuum
• Coil cleaner (non-corrosive)
• Multimeter (for electrical checks)
• Wet/dry shop vac (for drain cleaning)

📋 Maintenance Schedule Summary