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Aircon Compressor Not Working: The Big-Ticket Diagnosis
The compressor is the heart of your aircon — the condenser-mounted pump that pushes refrigerant around the loop — and 'aircon compressor not working' is the diagnosis people fear, because it's the expensive one. Two things worth knowing before the dread sets in: on Punggol's System 3/4 setups, one compressor serves your whole flat, so its failure is unmistakable; and a large share of suspected compressor deaths turn out to be a $40-part failure standing next to a healthy compressor.
The symptom signature
Indoor units behave — fans blow, lights on, remotes respond — but the air never gets cold, in every room at once. Outside, the condenser tells the story: its fan may spin while the compressor stays silent (no deep hum under the fan noise), or you hear clicking as it attempts to start and gives up, or the whole condenser cycles on and off in short bursts. That every-room-at-once quality is the key: single-room failures point at fan coils; whole-flat warmth points at the shared machinery.
The impostor: a failed capacitor
Compressors need a starting capacitor to spin up, and capacitors — cheap, hardworking components — fail far more often than compressors do. A dead capacitor produces near-identical symptoms: the compressor hums or clicks but won't start, cooling vanishes flat-wide. This is the outcome you're hoping for from diagnosis, because the fix is a modest component swap, not a heart transplant. It's also why nobody should accept a 'compressor's dead, need a new system' verdict delivered without testing: the impostor case is common enough to check every single time.
When it really is the compressor
Genuine compressor failures — worn out mechanically, windings gone, or damaged by running on low gas for months — present a fork. Repair means replacing the compressor itself: real money, sometimes worthwhile on a younger system. Replacement means a new condenser or full system: quoted per site. The honest arithmetic weighs the system's age, what else is nearing fatigue, and the repair-versus-replace gap. We lay out both numbers and give you the recommendation we'd take ourselves; because we do both repairs and installations, neither answer pays us more than the other.
How diagnosis proceeds and what to have ready
It's a $50 visit, waived if you proceed with the repair. The technician tests electrically at the condenser — capacitor, windings, protection devices, starting behaviour — plus gas pressure, since low refrigerant both mimics and causes compressor distress. Useful details to send on WhatsApp beforehand: does the condenser fan spin? Any clicking or humming? Did cooling fade gradually over weeks (suggests gas) or die overnight (suggests electrical)? Ledge-mounted condensers are our daily terrain, so access is handled as routine.
Frequently asked questions
How do I know it's the compressor and not something else?
You mostly can't from inside the flat — that's honest. What you can observe: all rooms warm simultaneously plus an abnormally quiet or clicking condenser makes compressor-circuit trouble likely. Whether it's the compressor itself or its capacitor takes on-site electrical testing, and the difference is hundreds of dollars.
Is a compressor repair worth it, or should I replace the whole system?
Depends mainly on age. Younger system with a one-off failure: repair usually wins. Older system where the compressor died of accumulated wear: replacement often beats pouring money into fatigued equipment. You'll get both quotes — repair fixed, installation per site — and our straight recommendation.
Can running the aircon with low gas kill the compressor?
Over time, yes — refrigerant also carries the compressor's cooling and lubrication, so months of running under-charged wears it prematurely. It's the strongest practical argument for fixing leaks properly instead of stacking top-ups: the top-ups are cheap, the compressor they're endangering is not.
Meanwhile, can I still run my indoor units?
They'll run fans without cooling, which is harmless but pointless. There's no damage risk in leaving indoor units on, but nothing gained either — better to book the diagnosis and use fans until it's sorted.
Whole flat warm and the condenser suspiciously quiet? Book the $50 diagnosis at /book or WhatsApp us the symptoms — capacitor impostors are common, and we test before we sentence.