Split Aircon Systems: What They Are, How They Work, and What to Watch For
- thesnowflakesg
- 7 days ago
- 3 min read
Summary
Split aircon systems are the most common type of residential cooling setup in Singapore. They consist of an indoor unit (FCU) and an outdoor unit (condenser), connected by refrigerant piping and drain lines. While efficient and compact, these systems still depend on proper sizing, installation, and maintenance to perform well. This guide explains how split systems work, where they fail, and what you need to maintain over time.
What a Split System Does
Split systems operate by separating heat extraction and rejection between two units:
The indoor unit (fan coil) draws in room air, cools it via the evaporator coil, and redistributes it.
The outdoor unit (condenser) expels the absorbed heat outside via the compressor and condenser coil.
Refrigerant circulates between both units, enabling continuous cooling without moving air between indoors and outdoors.
Key Components
• Indoor Unit (FCU)
Contains the evaporator coil, blower fan, thermistor, and PCB. This is where cool air is generated.
• Outdoor Unit (Condenser)
Houses the compressor, condenser coil, and fan. This is where heat is discharged.
• Refrigerant Piping
Connects the two units. Allows refrigerant to flow in a sealed loop — absorbing heat indoors and releasing it outside.
• Drain Pipe
Removes condensate (water) from the indoor unit. Improper gradient or blockage here causes leaks.
• Power Supply and Control Cable
Transfers electricity and communication signals between units.
Advantages of Split Systems
• Energy Efficient
Split systems only cool the room they’re installed in — no duct loss. Modern inverters adjust speed based on demand.
• Quiet Operation
With the noisy compressor outdoors, the indoor unit stays silent — ideal for bedrooms and living spaces.
• Cost-Effective Setup
Lower upfront cost than centralized systems. Great for HDBs, condos, and small offices.
• Scalable
Can install multiple units (multi-split) with one outdoor condenser — for homes with several rooms.
Common Split System Issues
• Weak cooling
Often due to dirty filters, low refrigerant, or blocked coils.
• Water leaking indoors
Caused by blocked drain pipe, tilted unit, or internal rust.
• Noisy operation
Usually due to dirty or imbalanced blower fans, worn bearings, or bracket vibration.
• System tripping
Faulty compressor, electrical faults, or PCB failure may cause power trips — especially during startup.
⚠️ Don’t assume “not cold” means it just needs gas. Proper diagnosis checks all components before topping up.
Maintenance Tips for Split Systems
• Clean filters monthly
Clogged filters reduce airflow, strain components, and cause the coil to ice up.
• Book servicing every 6–12 months
Includes deep cleaning of the coil, fan, and drain — preventing leaks and mold buildup.
• Check outdoor unit clearance
Keep the area around the condenser free of boxes, plants, or walls. Poor ventilation reduces performance.
• Monitor for early symptoms
Warm air, strange noises, or water stains should trigger a service — not a wait-and-see approach.
What Happens If You Ignore It
✖ Cooling performance drops and energy use spikes
✖ Leaks cause damage to walls, ceilings, or flooring
✖ Compressor or PCB may fail from prolonged strain
✖ Minor issues evolve into costly system replacements
Final Word
Split systems are reliable and efficient — when installed properly and maintained on schedule. If cooling feels weaker, airflow seems off, or the system is leaking, don’t guess. Get the full setup assessed before the problem escalates.
Weak cooling or water leak in your split system?