What you'll notice
The unit works for a moment and then the circuit breaker trips, usually at the instant the outdoor compressor tries to start. Resetting the breaker gives you the same result again.
Why it happens
Compressor start-up draws several times the running current, so anything that raises that draw will trip protection. A degraded start capacitor, a compressor with failing motor windings, a condenser coil so blocked that head pressure is abnormally high, or an undersized or shared circuit are the usual causes.
A breaker trip is a protection device doing its job, and the useful question is always what it is protecting against. On a split system, the moment of highest electrical stress is compressor start-up, when inrush current can briefly reach five or six times the running figure. Anything that raises that peak pushes it past the breaker threshold.
Why the coil matters
A condenser coil packed with dust, grass cuttings or coastal salt cannot reject heat properly. Head pressure climbs, the compressor works harder against it, and current rises with it. This is why a unit that has never been serviced often starts tripping in its third or fourth summer, having been perfectly reliable before. Cleaning the coil is frequently the whole repair.
When it is the supply, not the unit
Aircons are sometimes added to an existing circuit that was never sized for them, or share a breaker with other heavy loads. If the measurements show the unit drawing normal current on a circuit that cannot support it, the honest answer is a supply problem, and we will tell you that rather than replacing parts.
How we fix it
We measure start and run current against the unit rating plate, insulation-test the compressor windings, and inspect the condenser coil and the supply circuit. Where the fault is electrical supply rather than the unit itself, we say so — rewiring a circuit is electrician work, and we will not sell you a compressor to solve it.
Still not working?
If the checks above haven't restored your compressor, this usually needs a technician. Our Aircon Repairs service covers exactly this fault — from R650, quoted upfront.