Notice a puddle under your indoor aircon unit? In Singapore’s tropical climate, condensation is heavy, but leaks often signal a problem. Ignoring it can damage walls and cause mould.
1. Clogged Drain Pipe (Most Common)
- Why: Dust, bacteria, and algae block the narrow drainage pipe.
- DIY check: See if water drips from the outdoor pipe. If dry but indoor unit leaks → clog.
- Professional fix: High-pressure nitrogen flushing to clear sludge.
2. Dirty Air Filter
- Why: Restricted airflow causes evaporator coil to freeze, then melt excessively.
- DIY: Wash reusable filters every 2 weeks in Singapore.
- Pro tip: Replace disposable filters monthly.
3. Low Refrigerant Gas
- Why: Gas leak causes coil to ice up.
- Sign: AC runs but blows warm air, plus water leak.
- Solution: Licensed technician must find & seal leak, then top up gas (R32 or R410A).
4. Improper Installation (Wrong Slope)
- Why: Indoor unit must tilt slightly toward drain pipe. If level or backward → water overflows drip pan.
- Fix: Re-mount unit with correct gradient (only a professional).
5. Rusted or Cracked Drain Pan
- Why: Age or chemical cleaners corrode the plastic/metal pan.
- Solution: Drain pan replacement – common for units 7+ years old.
6. Blocked Condensate Pump (For concealed units)
- Why: Pump moves water upward. If blocked, water backs up.
- Sign: Error code on some Mitsubishi/Daikin units.
- Fix: Pump cleaning or replacement.
7. Oversized Aircon for Room
- Why: Short cycling (too powerful) doesn’t dehumidify properly.
- Solution: Right-sizing during next replacement. For HDB rooms, 9,000–12,000 BTU is typical.
When to Call a Pro
- Leak returns after DIY cleaning
- Water dripping from ceiling/light fixture
- AC smells musty (mould in ducting)
Prevention
Schedule aircon chemical wash twice a year in Singapore. Regular servicing (30–60 per unit) prevents 90% of leaks.
