Aircon not cooling? What to check before you call anyone
By True Line Air Conditioning · 5 min read
The short answer: if your split system runs but doesn’t cool, check the mode, the set temperature and the filters first — those three fix a surprising share of “broken” aircons. If the filters are clean and it still blows warm on a correct setting, stop there: the likely causes (refrigerant, sensor or electrical faults) aren’t homeowner-fixable, and running the system hard while faulty can turn a small repair into a compressor-sized one.
Five checks you can safely do
- Mode and temperature.The remote should show cool mode (usually a snowflake) — not fan, dry or auto — set a few degrees below the room temperature. It sounds obvious; it’s still the most common callout we could have fixed over the phone.
- Filters.Open the indoor unit’s front panel and look at the mesh filters. If they’re grey with dust, the system is suffocating — rinse them, let them dry fully, refit.
- Indoor airflow. Weak airflow with clean filters can mean a heavily soiled indoor coil — that needs a professional clean, not a bigger fan speed.
- The outdoor unit.Is it running? Is it choked with leaves, cobwebs or garden growth? It needs clear space to dump heat. Don’t open it — just clear around it.
- The basics. Windows shut, blinds on west-facing glass, and give it time — on a 40° afternoon an undersized system may be running flat-out and simply losing the race. Sizing is its own problem.
When it’s a real fault
Warm air on a correct cool setting, ice forming on the pipes or indoor coil, the outdoor unit not starting, or the system tripping the switchboard — these point to refrigerant loss, a failed sensor, a fan or compressor problem, or an electrical fault. Refrigerant work legally requires an ARCtick-licensed technician, and electrical faults need a licensed electrician — we’re both, which keeps the diagnosis honest and the fix in one visit.
What it costs to fix
We diagnose first and quote before repairing — how our repairs work. If the system is old enough that a repair doesn’t make sense, we’ll say so with numbers: here’s the repair-or-replace framework, and replacement pricing is published from our installed price list.
Still blowing warm after the checks? Book a service — same-week across southeast Melbourne, next-day priority for care plan members.
Know what your aircon will cost before you call.
Transparent published pricing, sized for your rooms in 30 seconds.