Your aircon has stopped working. It’s a stinking hot Perth afternoon, the temperature outside is pushing 42°C, and your unit is either blowing warm air, showing an error code, or simply refusing to turn on.
Before you pick up the phone and call a technician, there is one simple thing you should always try first — a reset.
Resetting your air conditioner unit takes less than 30 minutes, costs nothing, and fixes a surprising number of common problems.
Power outage tripped the protection circuit? A reset fixes that. Thermostat lost communication with the indoor unit? A reset fixes that too. Minor electrical glitch after a Western Power voltage fluctuation? Same answer.
This guide walks you through exactly how to reset your aircon unit in Perth, step by step, for every common unit type — split system, ducted, reverse cycle, and portable. In plain language, no jargon, and no guesswork.
Why Your Aircon Might Need a Reset in Perth
Before jumping into the steps, it helps to understand what is actually happening when your aircon needs a reset.
How Perth’s Climate Puts Extra Pressure on Your Unit
Perth summers are genuinely brutal. Temperatures regularly exceed 40°C for days at a stretch, and most households run their aircon units at full capacity for hours on end. That sustained workload puts real stress on the compressor and the electrical components inside the unit.
When a unit overworks in extreme heat, the internal protection circuit trips automatically as a safety measure. This is not a fault — it is your aircon protecting itself. But once that circuit trips, the unit will not restart on its own. A reset is what clears it.
Common Reasons Your Aircon Needs Resetting
Power outages and voltage surges are the most common trigger in Perth. When Western Power cuts out — even briefly during a summer storm — and power is restored, your aircon’s protection circuit often trips and prevents the unit from restarting automatically.
Other common reasons include the compressor overheating after running flat out through a heatwave, a thermostat communication error between the indoor and outdoor units, short cycling where the unit keeps switching on and off rapidly, and minor PCB board glitches in newer digital units that a power cycle clears instantly.
When a Reset Will and Won’t Help
A reset resolves minor electrical faults, communication errors, and protection circuit trips. It will not fix a refrigerant leak, a failing compressor, a severely clogged filter causing poor airflow, or any physical mechanical damage inside the unit.
If your aircon resets successfully but the same problem returns within a day or two, there is an underlying issue that needs a licensed technician to diagnose properly. And one important safety note — never attempt a reset if you can see exposed wiring, smell burning, or notice sparks anywhere near the unit. Switch power off at the switchboard and call a professional immediately.
The Standard Reset Method for Australian Aircon Units
Here is something worth knowing that surprises many Perth homeowners: most air conditioners sold in Australia do not have a dedicated reset button like some overseas models do.
Why Australian Aircons Are Different
The standard reset method for Australian aircon units — whether it is a Daikin, Mitsubishi, Fujitsu, Panasonic, or any other brand — is through the isolator switch located next to the outdoor unit, or through the switchboard inside your home.
This is called a hard reset, and it is the method recommended by most licensed HVAC technicians across Perth and the rest of Western Australia.
Simply flicking the isolator off for a few seconds and back on does not count as a proper reset — the unit needs to be fully without power for a meaningful period to allow the internal components to discharge and the control board to clear completely.
The Basic Reset Process — All Unit Types
This process applies to split systems, ducted systems, and reverse cycle units across Perth homes. Follow these steps in order and do not rush the wait times — they matter.
- Turn your aircon off using the remote control or wall controller. Do not skip this step — switching power off while the unit is still running can cause further issues.
- Locate the isolator switch on the wall beside your outdoor unit. It is a large plastic switch, often V-shaped or rectangular, mounted directly on the wall next to the condenser unit outside. Most Perth homes with a unit installed in the last decade will have one.
- Turn the isolator switch to the OFF position. Then go to your switchboard — usually in the garage, laundry, or a hallway cupboard — and switch the dedicated aircon circuit breaker to OFF as well.
- Wait a full 30 minutes. This is the most important step and the one most people shortchange. Thirty minutes allows the capacitors inside the unit to discharge fully, the PCB control board to clear, and the compressor pressure to equalise properly. Setting a timer on your phone helps so you are not guessing.
- After 30 minutes, switch the circuit breaker back ON at the switchboard first. Then switch the isolator back ON at the outdoor unit. Wait five minutes before turning the unit back on via the remote.
- Turn the unit on using your remote, set it to cool mode, and set the temperature at least five degrees below the current indoor temperature. Wait 10 minutes and observe — you should feel cool air coming from the vents and hear the outdoor compressor running steadily.
How to Reset Specific AC Unit Types in Perth
While the standard method above covers most situations, here is what to know for each specific unit type commonly found in Perth homes.
How to Reset a Split System Aircon in Perth
Split systems are the most popular aircon type across Perth homes and apartments — and the most straightforward to reset using the isolator and switchboard method above.
One additional tip specific to split systems: after completing the standard reset and turning the unit back on, check the indoor unit display for any error codes. Write down any code showing on the display before attempting another reset.
Daikin, Mitsubishi, and Fujitsu units all use specific error codes that tell a technician exactly what is wrong — clearing them with repeated resets without addressing the underlying fault can waste time and mask the real issue.
- For Mitsubishi Electric units, there is sometimes a small reset button behind the front panel of the indoor head unit. If the standard isolator method does not resolve the issue, open the front panel gently, locate the small button, and press it with a pen tip for five seconds before restoring power.
- For Daikin units, the reset button on some models is located near the display panel on the indoor unit. Hold it for 5 to 10 seconds. Check your model’s manual if you are unsure of the exact location, as it varies between Daikin models sold in Australia.
- For Fujitsu split systems, the isolator switch method works reliably. Turn the isolator off, wait 30 seconds minimum, then turn it back on. Some Fujitsu remotes also have an ACL or reset function — check the back of the remote for a pinhole button and press it with a paperclip to reset the remote itself if it has lost communication with the indoor unit.
How to Reset a Ducted Aircon in Perth
Ducted systems serve the whole home and the reset process is similar to split systems — with one extra consideration.
- Follow the standard isolator and switchboard method above, but extend the wait time to 30 minutes minimum given the size of the system. After restoring power and restarting, check that every zone controller in the home is responding and that airflow is reaching all rooms.
If your ducted system is showing an error code on the zone controller display, note it down before resetting. Persistent errors after a reset on a ducted system typically point to a sensor fault or duct pressure issue that needs professional attention rather than another power cycle.
How to Reset a Portable Aircon
Portable aircon units are the simplest to reset because they are standalone plug-in appliances with no outdoor unit to worry about.
- Turn the unit off using the control panel or remote. Unplug the power cord from the wall outlet completely — not just switch it off at the unit itself. Wait two full minutes to allow the internal components to discharge. Plug the unit back in, power it on, and set it to cool mode.
If your portable unit is plugged into a surge-protected power board, try plugging it directly into a wall outlet instead. A tripped surge protector is a surprisingly common cause of portable aircon failures that looks exactly like a unit fault.
After the Reset — What to Check
A successful reset is the start, not the finish. Once your aircon is running again, run through these quick checks to confirm everything is working properly.
1. Check Airflow and Temperature
Cool air should begin coming from your vents within five to ten minutes of startup. Place your hand near an indoor vent — you should feel noticeably cool air. If the air feels only slightly cool or still warm, the issue goes beyond what a reset can fix and a technician is needed.
2. Inspect Your Air Filter
A severely clogged filter is one of the most common causes of an aircon shutting down in the first place — and running the unit again with the same dirty filter just restarts the same problem. Pull the filter out and check it. If it is visibly grey with dust and debris, rinse it under warm water, let it dry completely, and reinsert it before running the unit again.
3. Listen to the Outdoor Unit
Stand near your outdoor condenser unit for the first few minutes of operation after a reset. A steady hum with the fan spinning normally is a good sign. Grinding, squealing, or repeated clicking from the compressor are warning signs that the reset has not resolved an underlying mechanical issue.
When to Stop Resetting and Call a Perth Technician
Resetting your aircon once is smart troubleshooting. Repeatedly resetting a unit that keeps failing is a different matter — it puts sustained stress on the compressor and can turn a repairable fault into a full compressor replacement.
- Stop attempting resets and call a licensed Perth aircon technician if your switchboard circuit breaker trips again immediately after a reset. Also call a professional if the unit restarts but stops working again within a few hours repeatedly, if you notice ice forming on the indoor unit or refrigerant lines, if the compressor makes grinding or clanking noises, if you smell burning from any part of the system, or if the same error code reappears immediately after being cleared.
- These are signs of a deeper mechanical or electrical fault — a refrigerant leak, a failing capacitor, compressor damage, or a PCB board fault — that a reset will never fix. A licensed HVAC technician in Perth can diagnose the root cause from the error code and fix it properly the first time, saving you from a much larger bill later.
- Any electrical work on your aircon system in Western Australia must be carried out by a licensed electrician. Refrigerant handling requires a valid ARC Tick licence — it is a legal requirement in Australia, not just a safety recommendation. Always check these credentials before any technician starts work on your system.
Frequently Asked Questions Aircon Reset in Perth
1. How do I reset my aircon unit in Perth?
Turn the unit off with the remote, switch the isolator off beside the outdoor unit, turn the circuit breaker off at the switchboard, and wait 30 minutes. Then restore switchboard power, restore isolator power, wait five minutes, and restart the unit via the remote. This is the standard hard reset method for Australian aircon units.
2. Does my Perth aircon have a reset button?
Most air conditioners sold in Australia do not have a dedicated reset button like some overseas models. The standard method is through the isolator switch beside the outdoor unit and the circuit breaker at your switchboard. Some Daikin and Mitsubishi models have a button on the indoor unit — check your model’s manual for its exact location.
3. How long should I leave my aircon off before resetting?
For split system and ducted units, wait a full 30 minutes. For portable aircons, two minutes is sufficient. The wait time allows the internal capacitors to discharge and the control board to clear properly — rushing it means the reset may not take effect.
4. Why does my aircon keep tripping after I reset it?
Repeated tripping after a reset points to an underlying fault — typically a failing capacitor, refrigerant issue, compressor stress, or electrical wiring problem. Stop resetting and call a licensed Perth technician after the second failed attempt. Continued resets will accelerate damage to the compressor.
5. Is it safe to reset my aircon myself in Perth?
Yes — the isolator switch and switchboard methods described above are safe for any Perth homeowner to carry out. Never open internal components, touch wiring, or attempt to handle refrigerant yourself. If you see exposed wiring, smell burning, or notice sparks, switch power off at the switchboard immediately and call a licensed technician.
6. When should I call a technician instead of resetting?
Call a licensed Perth aircon technician if the circuit breaker trips again immediately after a reset, if the unit keeps stopping after a few hours, if you notice ice on the pipes, grinding noises from the compressor, burning smells, or if the same error code returns straight after being cleared.
The Bottom Line
A reset is the first and often only thing your Perth aircon needs to get back up and running — and now you know exactly how to do it properly.
Use the isolator switch and switchboard method for split system, ducted, and reverse cycle units. Give the full 30-minute wait time. Check your filter, listen to the outdoor unit, and confirm cool airflow before calling it done.
If the reset holds and your aircon runs normally, great — you just saved yourself a call-out fee. If the same problem comes back within a day or two, that is your signal to bring in a licensed Perth technician before a small fault turns into an expensive one.
Perth summers are not the time to be without a working aircon. Reset it properly, maintain it regularly, and it will keep your home cool all season long.