These are the two components most responsible for aircons that appear to have died expensively but have not. Both are small, both are inexpensive, and both fail regularly in South African heat.
The capacitor
A run capacitor stores and releases charge to give the compressor and fan motors the phase shift they need to turn. It is a consumable part: heat cycling degrades it, and a capacitor rated at 35 microfarads that now measures 12 will leave a compressor humming and straining without ever starting. From outside the unit, that is indistinguishable from a seized compressor — which is exactly why capacitors should be tested before anything else is condemned.
The contactor
The contactor is the relay that switches mains power through to the outdoor unit when the indoor unit calls for cooling. Its contacts arc every time they close, and after a few summers they pit, burn or in some cases weld shut. Pitted contacts give intermittent operation; welded ones leave the outdoor unit running when it should be off.
Why this matters commercially
An installer who reaches for a compressor quote without measuring the capacitor is either under-equipped or not being straight with you. The test takes minutes with a meter that costs less than a single call-out. We do it first, every time, and a good proportion of no-cooling jobs are finished on the same visit because of it.
Brands we fit and service
The capacitor & contactor market splits into hardware built for South African conditions and lookalikes that fail at the first hard season. These are the manufacturers we trust on our installations:
- Generic and OEM capacitors for Samsung
- LG
- Midea
- Hisense
- Daikin
- Alliance
- Defy
See our brand guides for how these manufacturers compare.
When the capacitor & contactor goes wrong
These are the failures we're called to most often — each with its symptoms, causes and our fix on the dedicated problems page:
- Aircon hums but the outdoor unit will not start — A hum or buzz from the outdoor unit with no fan or compressor rotation, often cutting out after a few seconds and trying…
- Outdoor unit runs constantly or will not switch off — The outdoor unit keeps running even when the indoor unit is off or has reached temperature, sometimes with a noticeable …
Need this fixed or installed?
Our Aircon Repairs service covers capacitor & contactor work — from R650, quoted upfront and backed by our 12-month workmanship warranty.