Aircon Problems Guide: What Each Fault Really Means
- thesnowflakesg
- Feb 2, 2022
- 30 min read
Updated: May 26
Aircon acting up? Not cold, leaking water, strange smells, loud noise, or flashing errors? This isn’t just wear and tear. It’s your system sending a signal.
This guide breaks down real world faults we’ve seen across thousands of visits across homes and businesses. It's a clinical tool to help you spot what’s going wrong — and understand why the right fix starts with proper diagnosis.
The same symptom can hide multiple faults. And defaulting to surface cleaning won’t fix what’s deeper. (Click on the arrow to expand the points)
Cooling & Airflow Failures
Not Cold – Weak or warm airflow even when system is on
Still Not Cold After Servicing – Cleaning didn’t solve it
Only One Room Cools – Multi-split but partial cooling
Cold at the Vent, But Room Still Warm – No throw, no reach
Can’t Reach Set Temperature – Always running, never cold
Fan Spins, But Air Not Cold – Blower okay, cooling failed
Leaks, Moisture & Drainage Issues
Water Dripping from Indoor Unit – Tray overflow or choke
Water Backing from Drain Pipe – Slope or downstream choke
Leak Only After Shutdown – Residual water overflowing
Condensation on Trunking or Wall – Failed insulation
Wall Damp Near Piping – Hidden moisture from cold lines
Smell, Mold & Hygiene Signals
Musty Smell After Cooling – Mold inside blower or tray
Smell During Use – Sour, musty, or burnt odours
No Smell, But Weak Airflow – Coil or blower likely blocked
Burning Smell on Startup – Electrical risk, shut off fast
Noise & Outdoor Unit Behaviour
Indoor Unit Rattling or Vibrating – Fan or mount issue
Grinding or Buzzing Sound – Internal motor or blade fault
Outdoor Unit Louder Than Usual – Load or balance problem
Humming, But No Cooling – Compressor not engaging
Control, Sensor & Error Faults
Blinking Lights or Error Code – Brand-diagnosed fault
Remote Not Responding – Receiver or IR sensor fault
Turns On and Off Repeatedly – Sensor or logic error
Room Temperature Feels Off – Thermistor misreading
Startup & Electrical Failures
Unit Won’t Turn On – No lights, no fan, no response
Turns On, But No Airflow – Display works, blower dead
Starts Then Shuts Off – Load abort or coil fault
Breaker Trips on Start – High amp draw or shorted board
Fan and Lights Work, But No Cooling – Compressor fault
Outdoor Fan Not Spinning – Heat can’t escape, system fails
Repaired, But Still Not Fixed – Wrong diagnosis last time
Final Word
Weak cooling, leaks, noise, or system errors — we diagnose properly before recommending any fix.
No guesswork. No pressure. Just real answers.