Air Conditioner
Troubleshooting Guide

Check the circuit breaker in your switchboard, usually labelled Air Con or AC, or a general power circuit if there is no separate one. Make sure the isolator switch beside the outdoor unit is on, and that any power point near the indoor unit is switched on. If the remote’s screen is blank or dim, replace the batteries. If the breaker trips again after you reset it, leave it off and call Artarmon Air Conditioning.

Check the controller is on Cool, because the Cool and Heat icons look alike. Set it to around 21 to 24°C, make sure no timer or schedule is overriding it, and allow three to five minutes to start. Clean the filters and clear anything blocking the outdoor unit, then run it for 15 minutes. If it still blows warm, a refrigerant leak is a common cause, and topping up the gas is not a fix.

Often it is working normally. A split system can take three to five minutes to start heating, and in cold weather may briefly blow cool air during a defrost cycle. Check the controller is on Heat at around 21 to 24°C, clean the filters and run it for 15 minutes. On a multi-split, every indoor unit must be in the same mode. Still blowing cold? Book a repair.

Turn the system off at the remote or wall controller, then switch off the power at the circuit breaker or the isolator beside the outdoor unit and leave it off for five minutes. Switch the power back on and wait a few minutes before turning the system on again. A reset clears minor glitches and some error codes. If the same fault or code comes back, it is a real fault and needs a technician.

Allow three to five minutes before it starts cooling or heating. In heating mode it may also blow cool air briefly during a defrost cycle, which is normal. To judge whether it is working, check the mode and temperature setting, then let it run for 15 minutes. If the room still is not changing after that, work through Artarmon Air Conditioning’s troubleshooting guide or book a technician.

Photograph the code on the controller. If the indoor unit flashes a pattern, such as four blinks, a pause, then two blinks, note it or video it. Then reset the system by switching it off at the breaker or isolator for five minutes. If the code comes back, book a repair and send the photo. Artarmon Air Conditioning’s error code guide shows how to read codes on the main brands.

First check that zone is switched on. Zoned ducted systems use a touchscreen, a remote or plain light switches, which are often in a hallway or near the return air grille and sometimes wired backwards, so off is on. Make sure the vents are open and not blocked by furniture, and clean the return air filter. If the zone still gets no air, a zone motor or damper has usually failed.

Most ducted systems read the temperature either at the return air grille, through a sensor in the indoor unit, or at the wall controller, and many can be switched between the two. If the return air grille is in a hallway, the system controls to the hallway, which is why bedrooms run too warm or too cold. Artarmon Air Conditioning can change which sensor is used or fit a remote sensor in the main room.

Every indoor unit on a multi-split shares one outdoor unit, so they must all run in the same mode. If one is set to cool and another to heat, the system may not run properly or may drop to fan only. Set every indoor unit to fan for one to two minutes, then switch them all to cool or all to heat and run it for 15 minutes. If not, reset it at the breaker.

Usually a blocked condensate drain, or ice melting off a coil that froze because the filters are clogged. Switch the system off. If water is reaching a ceiling or wall, switch it off at the isolator as well, and do not run it until it has been looked at. Leaking water is one of the faults to call a technician for. Artarmon Air Conditioning clears and flow tests the drain on site.

A musty smell often means dirty filters, so clean them first. If the filters were blocked, or the smell is still there for the first minute or two after it starts, mould and bacteria are usually growing on the indoor coil and fan barrel behind the filters, which a filter clean cannot reach. That needs a deep clean. A burning smell is different: switch the system off and call a technician.

Wash them, then get in touch. When filters block up, the air conditioner starts pulling dust through them, so the coil and fan behind may need a deep clean or the filters may need replacing. On wall units the filters are under the front cover, on ducted systems behind the return air grille. If the unit is in a bulkhead or ceiling void, do not try to reach them yourself.

Remove anything loose sitting on or near the indoor unit, and clear plants, bins or storage from around the outdoor unit. If the noise carries on, switch the system off and call a technician. A buzz at start-up with no start usually points to a capacitor or contactor, grinding from the indoor unit to the fan barrel or its bearings, and a rattle outside to loose panels or a damaged fan blade.

Reset the breaker once. If it trips again, leave it off and call Artarmon Air Conditioning. Repeated tripping means an electrical fault, such as a compressor or fan motor shorting to earth, water in the outdoor isolator, or damaged cable, and the breaker is doing its job by cutting the power. Resetting it over and over can make the damage worse.

If the screen is blank or dim, or the buttons do nothing, replace the batteries. Most handheld remotes take two AAA. If the display still does not come on, check the breaker and the isolator beside the outdoor unit, then reset the system. If a remote or wall controller stays blank after new batteries and a power reset, call a technician to check the controller and the board behind it.

Call Artarmon Air Conditioning if you cannot reach the filters, if the filters were blocked, if there is leaking water, a burning smell or a loud unusual noise, if the controller stays blank after new batteries and a power reset, if an error code returns after a reset, or if the system still does not work after every check. Do not open covers or try to top up gas yourself.

Yes. Artarmon Air Conditioning’s breakdown call is $299 including GST, and it covers attendance and the initial diagnosis of the fault whatever the cause turns out to be, including a tripped breaker or a dirty filter. That is why this guide exists: a few minutes of checks can save you the call. Any repair beyond the diagnosis is quoted at a fixed price before work starts.

Book online or call 0430 517 009. Describe the problem, attach a photo of any error code or a video of the flashing lights, and tell us when you are home. Photos of the model labels on the indoor and outdoor units help us bring the right manual and parts, but only if you can reach them safely. Artarmon Air Conditioning will then contact you to book a time.