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Common Air Con Faults, And How To Solve Them
Common Air Con Faults, And How To Solve Them

Advice and News •

Common Air Con Faults, And How To Solve Them

In the economic boom following the second world war, air conditioning became a must-have accessory for Australians, especially for those living in the northern areas of the country. Today, nearly half of all Australian households have air conditioning, with roughly five million units helping to convert stifling heat into refreshing coolness, and keeping our fellow citizens comfortable.

As a complex piece of machinery, air conditioners are susceptible to breaking, and when this happens, the sweat on your brow will encourage you to fix it as quickly as possible. In this article, we’ll explore a range of common air con faults, so that you understand how to troubleshoot an air conditioning unit, to figure out why your air con is not working.

Air con faults that you can fix yourself

Unplugged unit

An unplugged unit is one of the most obvious problems, but surprisingly common. It might have been temporarily unplugged from its outlet or turned off at the isolator, your kids might have knocked it out, or maybe your cat decided to wrench it out with its teeth, after succumbing to a feeling of extreme malice. When your air conditioner is busted, this is the problem you hope for.

Check your air conditioner’s circuit breaker

Circuit breakers help to protect electrical components from surges of electricity, which can happen when bolts of thunder strike power lines, or when the power grid restarts after being shut off. If you’ve experienced either of these recently, it’s possible that the circuit breaker has been tripped for the air conditioning system. To check this, open your electrical box, and locate the circuit breaker that should be labelled “AC.” If it has tripped, try to reset it.

Dirty filters

As air circulates through the air conditioner, it collects dirt, dust, and other particles, and quickly becomes filthy. This causes the system to work harder, which puts stress on its components and can lead to breakages. When your air conditioner’s filters are dirty, you’ll pay more in electricity, and are at risk of health issues such as asthma, weakened immune systems, and even lung disease6.

Gold-standard manufacturer Daikin recommends to clean or replace a split system air conditioner’s filter every month, or more frequently if you live in a particularly dusty or polluted environment2.

Split system air conditioners have washable or disposable filters, which you can determine by reading the unit’s instruction manual. If it’s a disposable filter, you’ll need to replace it. If it’s washable, you can easily clean by removing the unit’s cover, sliding out the filters, and vacuuming them. If stubborn dirt remains, wash them with warm water and a cloth, allowing them to dry before reinstalling.

Air con faults that a technician will need to fix

Refrigerant levels

Refrigerant is the magical substance that converts hot air into cool air. It constantly changes from liquid to gas as it moves through the system, allowing it to absorb and release heat3.

An air conditioning system requires a precise amount of refrigerant to function efficiently, and varies from system to system. If the system is low on refrigerant, either from a leak or a technician error, it won’t perform as effectively, and will increase your power bill.

Refrigerants are also damaging to the environment, so for the sake of our warming planet, it’s critical for a technician to identify and fix leaks4.

Electrical controls

Over time, an air conditioner’s electrical components can wear out, especially if the system is turned on and off frequently. Wiring can also be nawed on by voracious vermin living around your property, which will break your air conditioner, and sizzle the culprit. This can damage your air conditioners PC boards, and trip the circuit breaker.

A technician will be able to identify and fix electrical issues in your air conditioning system.

Condensate drain

The condensate drain is responsible for removing condensation produced by the system’s evaporator coil. When the line becomes dirty and clogged, it increases humidity, produces musty smells, and can create water damage in your home5. An air conditioner technician will be able to clean the condensate drain and prevent these issues from occurring.

Frozen evaporator coil

The evaporator coil contains refrigerant that converts warm air into cool air, and for optimum performance, should maintain a temperature of around 4°C. If you have dirty air filters, the system’s airflow will be reduced, which can cause the evaporator coil to become cooler, and eventually frozen2. To fix this problem, you’ll need the help of a professional.

Dirty condenser coil

The condenser is the unit that sits outdoors, and is responsible for removing heat from the air conditioning system. Being outdoors, it’s easy for the condenser’s coil to become caked with dirt, leaves, and twigs, making it work harder, and eventually breaking it.

While it’s possible to clean the condenser coil yourself1, it’s highly recommended to hire a professional, so that you don’t damage its delicate components. It’s also a good idea to keep the condenser clear of leaves, sticks, and other debris, to prevent further breakages.

Dislocated thermostat

Air conditioners use thermostats to regulate the temperature. When these get knocked out of place, or lose their calibration, they can’t measure the temperature effectively, and need to be corrected. A professional will need to reposition/calibrate the thermostat correctly.

Damaged ducts

Ducted air conditioners transfer air through ducts in the ceiling, which can be easily torn by possums, rats, or careless workers. When this happens, air isn’t able to circulate through the system as effectively, making the entire system work harder, and increasing your electricity bill. A professional will be able to identify and fix ducting tears.


Air conditioning ducting is handy building material for a rat’s nest. They’ll greedily snatch away large portions of the ducting for their homes, sabotaging the system’s air circulation.

Rats and mice can also chew through refrigerant lines, electrical wires, and other components of the system, causing all kinds of havoc. If they start living in the ducting itself, the air being circulated around your home can become contaminated with a toxic mixture of faeces, urine, and fur. The problem extends to all Australian creatures who can find their way into air conditioning systems: geckos, snakes, cockroaches, and possums, to name a few.

If you hear scuttling sounds coming from the ceiling, it’s worth hiring a professional to investigate.

Missed servicing

Most air conditioning systems should be serviced annually, although you should check your conditioner’s instruction manual for the recommended frequency. Like other complex machinery, air conditioners can quickly develop problems when servicing is missed, and will eventually fail. Regular servicing is essential to keep the system in good condition.

Faulty installation

If your system has been installed by a non-licensed technician, or a veteran who was having a terrible day and didn’t give two hoots about the quality of his work, you could have problems such as incorrect refrigerant levels, out-of-place thermostats, and leaky ducts. You’ll need to hire another technician to resolve these problems.

In our magnificent, blistering country, air conditioning has become a necessity, which is why almost 50% of Australian households have it. Unfortunately, air conditioning is complex, and there’s only so much troubleshooting you can do yourself before having to call a professional. Hopefully this article has given you a better understanding of common air con faults, so that you can decide whether to fix the problem yourself, or bring in a technician.

With a little luck, the problem will be a simple one to resolve, and you’ll be cool again in no time.


  1. Air Conditioner Coil Cleaning | How To Clean AC Coils, Carrier
  2. 2015, Simple Steps to Troubleshoot a Frozen Evaporator Coil, Byrd Heating & Air Conditioning
  3. 2015, How Refrigerant Works in an Air Conditioning System, Air Experts, Raleigh Heating & Air
  4. Common Air Conditioner Problems | Department of Energy,
  5. How to Clean Your Air Conditioner’s Condensate Drain Line | Home Matters blog |, American Home Shield
  6. Mould and your health,