How to Maintain a Split System Air Conditioner: A Simple Annual Checklist
Split system air conditioners are designed to run reliably for 10–15 years — but only if they're maintained properly. Neglecting basic maintenance leads to reduced efficiency, higher running costs, poor air quality, and ultimately premature failure. The good news is that most of the maintenance you can do yourself, and it doesn't take long.
Here's a practical checklist you can run through once or twice a year.
1. Clean the Indoor Unit Filters (Every 2–4 Weeks During Heavy Use)
The filters inside the indoor unit are the first line of defence against dust, pet hair, and airborne particles. When they're clogged, the unit has to work harder, airflow is restricted, and cooling performance drops noticeably.
How to clean them:
- Turn off the unit and remove the front panel (usually a clip-on cover that lifts or slides out)
- Slide out the mesh filters — they're typically held in by light plastic tabs
- Tap them gently to dislodge loose dust, then rinse under lukewarm water
- Allow to dry completely in the shade (not in direct sunlight or a dryer)
- Replace before turning the unit back on
Never run the unit without filters installed — this allows dust to coat the evaporator coils, which is much harder to clean.
2. Wipe Down the Indoor Unit Body
The plastic housing collects dust and can harbour mould in humid conditions. Wipe it down with a lightly damp cloth — no chemical cleaners or sprays directly on the unit.
3. Check the Condensate Drain
Your indoor unit removes moisture from the air during cooling and drains it away through a condensate pipe. If this pipe gets blocked with algae or debris, water will back up and either leak from the unit or trigger an error code.
Signs of a blocked drain: water dripping from the indoor unit, a musty smell when running, or visible moisture on the wall below the unit.
You can flush the drain pipe with a small amount of diluted white vinegar or have a technician clear it with a vacuum pump during a service.
4. Inspect the Outdoor Unit
The outdoor unit needs airflow to function — if its fins are blocked by leaves, debris, grass clippings, or garden overgrowth, efficiency drops and the compressor runs hotter than it should.
- Clear any vegetation within 30 cm of the outdoor unit
- Remove leaves and debris from around the base
- Rinse the fins gently with a garden hose (don't use a high-pressure washer — the fins are delicate aluminium)
- Check that the unit is level and that the mounting bracket or pad hasn't shifted
5. Inspect the Refrigerant Lines
The insulated pipes connecting the indoor and outdoor units should be intact and covered. If the insulation has deteriorated, UV exposure or physical damage can compromise the refrigerant lines over time.
If you notice frost on the pipes, ice forming on the indoor unit, or reduced cooling despite the unit running normally, this can indicate a refrigerant issue — call a licensed refrigerant technician.
6. Test All Operating Modes
At the start of summer and winter, run a quick test of all operating modes — cooling, heating, fan, and dry mode if your unit has it. This confirms everything is functioning before you need it urgently.
Check that the remote control works properly and that the unit responds to temperature changes as expected.
7. Book a Professional Service Every 2–3 Years
Even with good self-maintenance, a professional service every two to three years is worthwhile. A technician will check refrigerant levels (you cannot do this yourself — it's regulated), clean the evaporator coils with specialist equipment, test electrical connections, and inspect the compressor.
Signs Your Air Conditioner Needs Professional Attention
- Reduced cooling or heating output despite running normally
- Unusual noises: rattling, hissing, or grinding
- Ice forming on the indoor or outdoor unit
- Water leaking from the indoor unit
- A musty or mouldy smell when running
- Error codes displayed on the unit or remote
- Significantly higher running costs than normal
Brands We Stock and Service
Oceania Appliances sells split systems from Daikin, Fujitsu, LG, Mitsubishi Electric, Samsung, Panasonic, and other leading brands. If you need a replacement unit or have questions about an existing installation, call us or visit our showroom at Wetherill Park, open 7 days.