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Aircon Compressor: What It Does, Common Problems, and What to Watch For

  • thesnowflakesg
  • Sep 9, 2023
  • 2 min read

Updated: May 8

Summary

The compressor is the core engine of your aircon system — it pressurizes refrigerant, drives circulation, and powers the cooling cycle. If it fails, cold air stops completely. Compressor issues often go unnoticed until it’s nearly too late, with symptoms misread as low gas or minor faults. This post outlines how compressors fail, what to watch for, and what to do before a full breakdown occurs.


What the Compressor Actually Does

The compressor is the most critical — and costly — component of any aircon system. Its job is to compress refrigerant gas and move it through the system, enabling heat extraction from indoors and release outdoors. Without a functioning compressor, the entire system fails to cool.


What Damages an Aircon Compressor

Electrical faults

Power surges, short circuits, or faulty capacitors can burn out the compressor’s internal circuits or relay board — preventing startup or causing frequent tripping.

Refrigerant issues

Low gas levels, contamination, or poor charging procedures lead to high internal temperatures and pressure imbalances. Over time, the compressor strains to compensate and wears out faster.

Overuse and poor maintenance

Dirty filters and blocked condenser coils trap heat inside the system. This forces the compressor to work harder for longer — accelerating mechanical stress.

Age and mechanical wear


As systems age, internal seals degrade, bearings loosen, and compression efficiency declines — often without symptoms until critical failure.


⚠️ Note: Compressor faults can mimic gas leaks, PCB errors, or coil issues. Only a proper diagnostic confirms the true root cause.

Repair or Replace?

Most compressor failures require full replacement. The component is sealed, precision-driven, and under high pressure — internal repairs are rarely viable or reliable.


Correct diagnosis is essential. Compressor-like symptoms can also be caused by:

✦ Faulty PCB

✦ Fan motor malfunction

✦ Dirty condenser coil

✦ Refrigerant leak


Misdiagnosing the fault leads to unnecessary replacement costs and downtime.


How to Extend Compressor Life

Maintain airflow around the outdoor unit

Ensure the area is clear of plants, clutter, or obstructions. Poor ventilation leads to overheating.

Service regularly

Routine maintenance catches early warning signs like coil blockage, electrical loading, or pressure imbalance — before compressor stress builds.

Use balanced temperature settings

Avoid running at 18°C constantly. Use timers or eco modes to reduce load, especially overnight.


If Left Unchecked

✖ Compressor will overheat and trip under thermal protection

✖ Cooling output may drop or stop entirely

✖ Full compressor replacement is among the most expensive aircon repairs

✖ Further damage may occur to PCB, fan system, or electrical board


Final Word

Weak cooling isn’t always caused by gas loss. When the compressor is under strain, symptoms often surface too late. If your aircon struggles to cool, trips unexpectedly, or sounds irregular — get the system diagnosed early before deeper faults develop.


Suspect your compressor is under stress?

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