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How do I reset my air conditioning unit?

Sometimes your air con may not work as expected, and you may think it’s time for air conditioning repairs.  BUT, there are some things you can do first before calling aircon contractors to investigate your system and fix the air conditioner in your home or business.

One of those things is resetting your air conditioning unit.  Many brands of air conditioner come with a reset button that you can use if your air conditioning unit presents minor mechanical problems and/or trips out.

If your brand or model doesn’t have a reset button, you can use the isolation switch to reset the AC system.  Alternatively, you may use the power point for older split systems and window air conditioners.

If your AC unit doesn’t have a reset button, isolator or power point, you may be able to flip a circuit breaker or safety switch to restore the working of an air conditioner.  This calls on a visit to the switchboard.

If you need to reset your air con, your actions will largely depend on the features and way your air conditioner was installed.  Remember that it doesn’t matter what type of air conditioning you have, it should be possible to reset it.

Keep reading to find out the steps for your specific commercial or home air conditioner.

Use the AC reset button

Locate the reset button

Firstly, if you are lucky enough for your air conditioning unit to have one, you will need to find the reset button located on or around your aircon unit.

It should be relatively visible.  If you can’t find it, we recommend referring to the AC operations or user manual to see where it is located.

The button is usually red, and it should be clearly labelled as a “reset” button.

Press the reset button

Once you locate the button you can press it for three seconds and realise it.  Wait for a few seconds and press it again for three seconds.  The unit will usually respond after three beeps.

This should be enough to reset your air conditioning unit.

If you don’t have a reset button

If unfortunately you cannot find a reset button then you will have to try the next step.

Even if you do have a reset button, you may choose to do further resetting of the air conditioner at the power supply.

Reset air conditioning unit via isolation switch

Locate the isolation switch

To reset an air conditioning unit, you can isolate power at the isolation switch.  It is often called an isolator as it is designed to isolate power to the aircon unit.

Aircon isolator

The isolation switch usually has a lever, knob or dial with “on” and “off” positions and should be located at the condenser.  However, for older air conditioning systems, it might be a switch near the indoor unit and look just like an ordinary light switch.

Turn the isolator off

Turn the isolator into the “off” position.  Leave it off for at least 30 minutes.

This allows components in the air conditioning unit to reset, especially printed circuit (PC) boards in newer air conditioner brands and models that are electrically based.

Please note that even when there is no power to the air conditioner, there can still be electrically charged components within it.  For example, capacitor prongs within an AC unit can hold their charge for over half an hour.

Turn the isolator on

Once over 30 minutes has passed, turn the isolator into the “on” position.

Then turn the air conditioner back on.  Test run the air conditioning to see if it is operating correctly now.

If the air con is still not working, you can try resetting via the switchboard method below.  The isolation switch may be faulty, or you may choose to reset the air conditioner further.

If you don’t have an isolation switch

Firstly, if you don’t have an isolation switch and you have anything other than a window unit or portable air conditioner, then your air con system is not compliant with current Australian Electrical Standards.  When the system is replaced, an isolator will need to be installed.

If you have an older wall split system, window air conditioner or portable aircon, you can use the following power point reset method.

If you don’t have an isolator AND also no power point to work with, you will need to jump ahead to the switchboard reset method.

Reset air conditioning unit via power point

If you have a portable air conditioner, window box aircon (aka room air conditioner or RAC) or old wall split system, you can find a power point at the indoor unit.

Air conditioner in wall

Turn the power point off

Firstly, turn off the power point.  It may seem simple, but it is an important safety step to complete before moving on.

Unplug cord from power supply

Once power is switched off, remove the power cord from the power point.  This is the only way to make sure your air conditioner is not receiving power as power points can be faulty.

Leave for 30 minutes.  Let the internal components lose their charge and reset within the air conditioner.

As mentioned previously, it’s worth noting that even when there is no power to the aircon unit, some electrical components can still hold their charge for half an hour or more.

Plug the cord back in and turn on

Once over 30 minutes has passed, plug the power cord back into the wall in full.  Then turn the power point on.

Electric Plug

Test run the air conditioning unit to see if it now works correctly.

If it is still not working, plug another appliance into the power point to test if the point is working correctly.  If the power point is faulty, contact a fully qualified Electrician to assist.

If the power point is working but the air conditioner is not, you can try resetting the unit via the switchboard method below.

If you don’t have an accessible power supply

If your air conditioning unit doesn’t have a functional isolation switch or power point at the outdoor condensing unit or indoor head unit, as well as no reset button, then you will need to try the switchboard reset method.

You may also choose this method to take your air conditioning reset to the next level.

Reset air conditioning unit via switchboard

Switchboard in full with large AC switch

Locate the switchboard

First you will need to find your switchboard.  You can usually find it in the garage, basement, laundry, or at the side of the house.

It could be in a cupboard or enclosed space.  If you still cannot find it, refer to your original house plans or ask the previous owner or builder.

Safety first

It is important to take great care at every stage of resetting your air conditioner.  However, this is even more important while working on the electrical panel.

If you are not familiar or comfortable with your switchboard and its components, please contact an experienced Electrician to assist.

Open the switchboard

Open the door of your switchboard to gain access.  You may also need to open a second cover over various components within the outer panel.

Full switchboard with cover

This will give you access to the fuses, circuit breakers, and/or residual current device (RCD) safety switches.  Circuit breakers are sometimes called fuses, but they are actually quite different to fuses.

Locate the air conditioner switch

Locate the circuit breaker or safety switch that belongs to your air conditioning unit. Sometimes it is clearly labelled.  Sometimes it is not.

Turn the breaker or switch off

Flip the switch or breaker to the “off” position and wait for at least 30 minutes.

Flipping switch

If you have fuses, you cannot reset the air con in the switchboard with a simple on/off.  Fuses cannot be reset, only removed or replaced.

To reset your air conditioner fuse, you would need to remove then reinstall the fuse.  You can use the existing fuse if it is still in good condition or replace it with a new one at a small cost.

Turn the breaker or switch on

Once over 30 minutes has passed, turn the circuit breaker or safety switch back on in the switchboard.  Then turn the air conditioner back on and test it.

If your air conditioning unit is still not working, and you have tried all possible methods outlined above, it may be time to contact an air conditioning repair Brisbane technician to investigate further.


It is recommended to also do the following:

  • Check that you have a regular power supply before attempting to reset your air conditioning unit. To ensure your power is flowing evenly you can turn on a light and check for consistent brightness.
  • Inform everyone in your household that you will restart your air cond units. Ask them not to interfere while you are carrying out the whole process.

Cases in which you need to reset your AC unit

  • You may need to reset your air conditioner if it has experienced a significant fluctuation in power. This can occur due to a sudden black out, brown out, or surge in the power supply.
  • You may need to reset your aircon unit if an internal component is damaged or intermittently faulty, causing the air conditioner to stop working or not work properly.

You may need to reset your ducted air conditioning system it if the thermostat is malfunctioning or is not working properly.

Hot weather when air conditioner is not working

Cases in which you need to call a professional

Remember that if after you reset your air conditioning unit it is still not cooling or heating, you may need to contact a qualified HVAC technician to check on the air con units.

If the air conditioner is still under warranty, you may wish to contact the manufacturer.  However, just be mindful that if the issue is found not to be warranty related, they will charge you for their visit which may be more expensive than a normal air conditioner contractor.

Underlying mechanical problem

Frequent malfunctioning typically indicates underlying mechanical problems that should be resolved in order to fix air conditioner units and prevent larger aircon repairs.

If an air con is slow to cool down or warm up, it may just need air conditioning servicing.

If servicing an air conditioner doesn’t work, your AC is not cold enough or the aircon is not cooling at all, it is recommended to call a professional.  There is nothing worse than being stuck with a hot air conditioner on an even hotter day!

Exposed wires

If an AC unit or switchboard panel has exposed wires, you need to call a professional immediately.  If you reset the aircon under these conditions, you will put the safety of yourself and those around you at risk.  Exposed wires can cause shock, electrocution and fires.

Furthermore, if the wire is exposed inside the unit and you restart the air con, you may cause permanent damage to the air conditioner.  Worst case you will end up having to contact an aircon installer to replace the air conditioning units if repairs are not financially viable.

Resetting your AC too often

It’s worth keeping in mind that resetting your air conditioning unit too often may cause problems with your AC system.  There may be no other reason to reset it constantly other than an internal malfunction.  Continuing to run the air con in this state can lead to major air conditioner repairs and potentially larger expenses.

Male air conditioner technician

Perform regular maintenance

When performing regular air conditioner maintenance, an expert can determine why you may need to reset your air conditioning unit often.  He or she will be able to find the main problem, fix the aircon and help prevent it happening again.

Also, a Refrigeration Mechanic can check the refrigerant levels, check/clean/replace the air filters and examine the internal evaporator unit as well as the external condensing unit.  Their purpose is to make sure the air con system is working as designed on completion.

As you can see, resetting your air conditioning unit is not hard, but you have to be sure it is suitable for to your system and situation.

If you have any questions regarding resetting your air conditioner, or any other air conditioning related questions, we will be happy to help.  Please don’t hesitate to contact us to discuss.