Split systems are a go-to choice for heating and cooling, thanks to their quiet performance, energy efficiency, and compact design. But like any piece of machinery, they’re not immune to issues. Over time, even well-installed units can start showing signs of wear or develop problems that affect performance. If your system’s acting up, chances are it’s facing one of these common issues. Here’s what typically goes wrong and how professionals approach the fix.
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Not Cooling or Heating Properly
This is probably the first thing people notice. The system’s running, but the room just isn’t reaching the right temperature. Sometimes, it feels like the air isn’t even changing at all.
What’s Usually Going On:
- Dirty filters – When filters are clogged, airflow is restricted, and the system has to work harder. This reduces efficiency and can stop it from heating or cooling effectively.
- Blocked outdoor unit – Leaves, dirt, and debris around the outdoor condenser can impact heat exchange.
- Low refrigerant levels – If the refrigerant has leaked, your system can’t absorb or release heat properly.
- Thermostat issues – Incorrect settings or a faulty thermostat sensor can throw the whole system off.
How It’s Fixed:
A pro with experience in split system repairs Melbourne will usually start by checking the airflow and inspecting the filters. If they’re clean, the next step is checking refrigerant levels, examining the coils, and making sure the thermostat is calibrated and working as it should.
Strange Noises
Split systems are known for being quiet. So, if yours suddenly starts rattling, buzzing, clicking or humming louder than usual, something’s definitely off.
What’s Usually Going On:
- Loose parts – Screws, panels or fan blades can loosen over time.
- Fan motor problems – Worn bearings or failing motors can cause grinding or squealing noises.
- Debris stuck inside – Sometimes a twig or even a small animal can get into the outdoor unit.
How It’s Fixed:
Professionals will inspect both the indoor and outdoor components. They’ll tighten any loose parts, remove debris, and test the motor and fan operation. If the fan motor is failing, it may need to be replaced.
Water Leaks
You might notice water dripping from the indoor unit, or even a small pool forming underneath it. This is usually a sign of a drainage issue, not something to ignore.
What’s Usually Going On:
- Blocked or broken drain line – Dirt and dust can build up in the condensate drain and cause water to back up.
- Damaged drain pan – Over time, the pan that collects condensation can crack or corrode.
- Poor installation angle – If the indoor unit isn’t level, water can pool in the wrong spot and leak out.
How It’s Fixed:
A technician will clear the drain line using a vacuum or specialised tool. If the drain pan is damaged, it’ll be replaced. They’ll also check the unit’s mounting to ensure it’s level and correctly installed.
Bad Smells Coming From the Unit
If turning on the split system makes your room smell musty, sour, or just plain odd, there’s likely something growing—or rotting—inside.
What’s Usually Going On:
- Mould and mildew – Moisture buildup inside the indoor unit can lead to fungal growth, especially if filters are dirty.
- Clogged drainage – Stagnant water is a breeding ground for bacteria and fungi.
- Dead pests – Small animals or insects can get inside and cause a nasty odour if they die there.
How It’s Fixed:
Professionals will give the unit a thorough clean, including coils, filters, and internal components. They may use antibacterial sprays or foggers designed for HVAC systems. If mould is persistent, the drainage system may need upgrading or repairing.
The Remote’s Not Doing Anything
It sounds simple, but a non-responsive remote control can lead people to think the whole unit’s broken.
What’s Usually Going On:
- Flat batteries – Easily overlooked, but dead batteries are often the culprit.
- Infrared signal issues – The sensor on either the remote or the unit could be faulty or blocked.
- Internal board fault – In rare cases, the control board inside the unit might have failed.
How It’s Fixed:
A quick check of batteries and the remote’s signal usually sorts it. If the issue runs deeper, the control board will be tested and potentially replaced.
The Unit Keeps Turning On and Off
If your split system is cycling more often than usual, it could be short cycling. This isn’t just annoying; it puts strain on the system and wastes energy.
What’s Usually Going On:
- Oversized unit – A unit that’s too powerful for the room reaches the set temperature too quickly and shuts off, only to start up again soon after.
- Dirty filters or coils – These can cause the system to overheat and shut down prematurely.
- Thermostat location – If the thermostat is in direct sunlight or too close to the unit, it can cause incorrect readings.
How It’s Fixed:
Technicians will check the unit size against the room’s specs and inspect all internal components for dirt or damage. Repositioning the thermostat or adjusting settings may also help.
When to Call in a Pro
It’s tempting to Google the issue, watch a few videos, and try to fix it yourself. For some basic tasks, like cleaning the filters or clearing debris around the outdoor unit, that’s totally fine.
But once you’re dealing with refrigerant, wiring, or internal parts, it’s best to leave it to someone qualified. Not only is it safer, but it also ensures the problem is properly diagnosed and fixed without causing more damage.
Keep Your Split System Happy
Most of these problems can be avoided or at least delayed by keeping up with regular maintenance. That means cleaning the filters every few months, making sure the outdoor unit stays clear of leaves, dust and dirt, and booking a professional service once a year.
A well-maintained split system runs better, lasts longer, and saves you money on repairs and energy bills. If yours is acting up, don’t ignore the signs.