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Air Conditioner Not Working

Air conditioning is no longer a luxury, but a life support system in regions like Queensland.  There is never a good time for an air conditioner to stop working.  However, arguably the worst timing is during summer and/or a holiday period.  A broken air conditioning in summer can not only make you ill or even be life threatening, but also significantly disrupt your comfort and derail your holiday plans.

There are many signs that an air conditioner repair service is needed.  Understanding AC issues and common causes of an air conditioner not working will help prevent and fix many of them.  Some quick fixes can get your aircon up and running again, while other issues will require a heating, ventilation, and air conditioning (HVAC) specialist.

This article highlights the top 5 issues resulting in air conditioning not working, potential causes, and possible solutions.  These tips are helpful for homeowners, business owners, renters, and air conditioning aficionados.


1. Air Conditioner Not Turning On

Sometimes an air conditioner won’t kick into action or is completely unresponsive.  There are several reasons why an air conditioner won’t turn on at all.

Tripped circuit breakers cause issues

This is for safety due to high voltage or power fluctuation.  Flip the breaker back on if safe to do so.  However, call in a pro if it keeps tripping.

Blowing fuse preventing operation

Fuses prevent overcurrent but wear out over time or when an AC is faulty.  Professionals should investigate repeated blown fuses for deeper issues.

AC isolation or shut off switch faulty

Damage or failure to this switch near the outdoor unit removes electricity to the system.  If damaged, an HVAC tech can repair or replace it.

AC problems can be controller/thermostat-related

When an AC system is running, document any faults you see.  It’s best to photograph or video these faults.  This will help a professional when your air conditioner has stopped working.  Please note any controller issues like corrosion and blown components will also require a professional.

Leaked or uncharged refrigerant can stop an aircon from operating

Call in an expert before handling refrigerant, for legal and safety reasons.  Also, please note that any leaks need to be repaired and system pressure tested before gas can be added.

Ice might freeze internal components in the evaporator coil

Many AC units will cause system to not turn on when iced up in order to protect itself.  The underlying causes here could be air filter blocked, gas shortage, fan failure, valve failure, combination of these, or many other factors.  Ice is best in your summer drink, not in your air conditioner.

Faulty start capacitor, soft starter, or compressor itself will prevent start up

Part failure, overheating, and power outages can harm these AC parts which are essential for compressor starting.  These call for professional air conditioner repairs.

Printed Circuit (PC) board/s may have failed

If a PC board is not communicating correctly, the aircon system may not be able to start.

Many of these issues can happen at any time, and typically require air conditioning repair service ASAP.   A tripped circuit breaker or fuse may be fixed fairly simply, but electrical components or refrigerant repairs require professional expertise.

Close up of hand turning air conditioner circuit breaker back on in switchboard

2. Air Conditioner Tripping Breaker

If an air conditioner trips a circuit breaker, there are many possible underlying causes.  The issue may originate anywhere from incorrect installation, to lack of maintenance, to an unavoidable breakdown.

AC units need amp-rated breakers

Unsuitable AC breakers trip and result in an air conditioner not working.  An electrician can change the AC to a larger circuit or upgrade the breaker and wiring.

Additional devices can overload the AC circuit breaker

With an increase in the number of electronic items used in our day-to-day life comes an increased risk of electrical overload.  Device rerouting or AC circuit dedication can fix this.

Electronic short circuits can occur from broken internal wires

Repair by professionals is essential to prevent overheating and fires, as well as for other safety and legal reasons.

Clogged air filters restrict airflow

This causing AC overheating and breaker trips as a result. Air filter cleaning or replacement can fix this issue.

Condenser coil debris can restrict airflow

This also leads to aircon overheating and breaker tripping.  Regular DIY air conditioning maintenance including coil cleaning helps prevent this.

Evaporator coils can freeze, causing the AC to require more electricity

This can be the result of dirty coil, gas shortage, or faulty component/s.  Chronic difficulties require professional treatment, while coil thawing and cleaning can help.

Leaks or damage to refrigerant lines increases AC equipment strain and power usage

This increased power consumption can trigger the breaker to trip.  Professionals should be called in to search, repair, and recharge for aircon gas leaks.

Fan motors might draw high power

If there is an issue with a condenser or evaporator fan, higher than normal power may be drawn.  This normally needs professional air conditioning repair or replacement.

Faulty compressor can cause short circuits or difficulty starting

This can result in breaker trips.  Hard start kits or system replacement may be needed depending on severity.

Erosion of AC cables and insulation can create shorts

This happens naturally overtime and causes circuit breaker trips.  Harsh environmental conditions accelerate this process in sea-side locations such as Gold Coast and Sunshine Coast in Queensland.  An HVAC expert can diagnose and help resolve these issues.

Extreme heat makes AC units work harder, overloading the circuit

While we have limited control over the outdoor temperature, increasing airflow and cleaning may fix this issue.  However, if the system is small and older (8+ years), a whole new system may be required.

Circuit breakers wear and damage over time

Like an air conditioner, breakers wear out over time through use or constant tripping. Replacement with suitable certification require an HVAC technician or electrician.

Most of these issues, especially electrical or refrigerant ones, require a pro.  A professional can inspect, test, assess, repair, or replace for safety and performance.  However, the importance of regular aircon service cannot be forgotten to help reduce issues.


3. Air Conditioner Turns Off and On Repeatedly

Working one minute, shut down the next – Not what you want from your air conditioner!  An air conditioner turning on-and-off or short cycling can be caused by many issues.

Broken controller/thermostat can cause AC to switch on or off at the wrong time

Faulty wiring or battery power may cause this.  Depending on the controller, you may be able to check and replace batteries yourself.  For anything beyond this, a professional HVAC tech can help.

On and off cycles can result from the thermostat/controller being in the wrong location

If the temperature-detecting device is near an air vent or window, then it may not accurately measure room temperature.  It is recommended to move the device to improve detection.

Clogged or damaged air filter can restrict airflow

This makes the AC system work harder and overheat, causing short cycling. Cleaning or replacing the air filter usually fixes this.

Unclean exterior condenser coils cause AC overheating and short cycles

The length of the shut down period will vary greatly, depending on the extent of the issue.  Majority of the time this can be fixed by cleaning the coil.

Broken compressors overheat, cycling units on and off until they fail

A new AC compressor may be needed depending on age and condition.  For a wall split system, repairs tend not to be financially viable.  For a ducted system, age/condition of current system should be fully evaluated, and costs weighed up against alternative options.

Capacitor damage can cause AC unit to function intermittently

Damaged units may briefly cycle due to power loss.  Then they may turn off and on sporadically.  Technicians must diagnose and fix this issue to risk of electrocution with capacitors.

Air conditioners may turn off and restart to melt ice

Component failure, refrigerant leaks, dirty coils, and clogged air filters can all cause this issue.  It is best to call in a technician.

Float switch on modern AC units switches off when the drain pan is full

When the pan water level drops, a partially clogged drain line may stop and restart the machine.  To resolve the issue, drain line should be cleared.  In the long term, preventative maintenance is key.

Oversized air conditioner cools the space too quickly

This results in shortened cycling, where the AC cycles off quicker than normal.  This wears out internal components faster, shortening aircon lifespan.  HVAC professionals can size correctly and replace such faulty AC units.

Home air conditioner turning off with man trying to get AC remote to work


4. Air Conditioner Not Blowing Cold Air

Air conditioners that don’t blow cold air are not much good with the heat of summer!  While the AC may turn on, it’s not working if it’s not cooling when you need it.  There are many common causes.

Settings can be wrong

Check the controller for “cool” instead of “heat” or “fan”.  A controller or thermostat may need professional repair or replacement.

A blown fuse or tripped breaker can prevent cold air

If safe to do so, check and restore power at the switchboard. While visual checks may be ok, call a Technician for any further issues.

Airflow can be reduced by blocked filters

As part of monthly or seasonal preparation, air filters should be checked and cleaned or replaced as needed.

Debris might jam the exterior condenser

This can prevent heat release and cause an aircon to not blow cold air. Cleaning condenser coils requires great care and expertise.

Leaks reduce refrigerant, preventing cold air

For safety and legal reasons, fully licenced professionals are required to located and fix refrigerant leaks.  In Australia, look out for an ARCtick

Defective blower fans, motors, or compressors may impair cooling

If a major air conditioning component is faulty, the system can not function correctly.  As a result, the air conditioner will not blow cold air.

There may be duct leaks or obstructions

In this case, AC cooling may be limited as cold air is lost into the ceiling space.  For safety reasons, calling in the pros is recommended.  Also, who wants to crawl around in a hot ceiling?!  Even if it is cooled slightly by escaped air.

Iced evaporator coils will prevent cold air production

Common causes include clogged air filters, low fan speed, gas shortage, or unclean coils.  Hire a pro to thaw and clean a coil, then they can investigate further to find the root cause.

Large or small AC units might impair cooling

Like Goldlocks, you want to find the one that is just right.  Determine your home or business HVAC size with an expert to ensure cold air continues to flow.

Regular controller inspections, filter maintenance, and condenser zone clearing and cleaning can prevent numerous issues.  However, refrigerant leakage, electrical difficulties, component failure, and frozen coils require professional air conditioner repair.


5. Air Conditioner Not Cold Enough

What do you do when the air conditioner is running but room is not cold enough?  It all depends.  There are some basic things to consider, like indoor heat load when first turn the AC on, running time, and expectations of what the unit can achieve.  If these have been considered and air conditioner is still not cold enough, there could be further issues.

A simple setting issue may affect cooling

It is recommended to avoid the “auto” function when seeking cooling.  Set the AC to cool and medium-high fan speed where appropriate.  Be mindful that ducted systems have unique fan speed recommendations with zoned air conditioning (e.g. avoiding high fan with an iZone system, etc.).

Heat transfer may be reduced on indoor and outdoor AC coils

Dirty coils limit cooling ability and efficiency.  Ensure coils have been maintained and are clean enough for effective heat transfer.

Obstructions can impact heat discharge from outdoor unit

Plants, bushes, garbage, and personal belongings can obstruct heat discharge from condenser coils.  This reduces ability of the air conditioning system to release heat and cool effectively.

Blocked air filter can reduce AC cooling

Pet and dust dander can easily clog air filters. Regularly check filters and clean only when dirty.  Beware: overcleaning can shorten the filter media lifespan, wearing out filters quicker than needed.

Air conditioner may be short on refrigerant

Refrigerant leaks lower cooling capacity.  To resolve this issue is quite a process; reclaim or pump down of any remaining gas, nitrogen charge, leak search, repair/s, potential part replacement, pressure test, evacuation, recharge, commission, and test run.

AC compressors lose efficiency over time or due to sudden damage

Compressor issues can occur gradually (e.g. aging, overuse, etc.) or suddenly (e.g. gas leak, physically impact, etc.). A faulty or inefficient compressor drastically reduces AC cooling.

Ductwork may be leaking air

This will reduce the amount of cold air and subsequent cooling throughout the indoor area.  Ductwork can be impacted by age, animals, or area disruption.

Component failure can reduce cooling

Air conditioners have dozens if not hundreds of components, and failure of any number of these can cause an AC to not cool enough.  Common culprits include PC boards, capacitors, transformer, valves, etc.  Best to call in the pros to identify and resolve these issues.

Fortunately, many of the issues resulting in air conditioner not cooling enough can be resolved.   Some involve DIY fixes, while other require an HVAC professional.  Experts should diagnose and repair complex issues such refrigerant leakage, compressor failure, and frozen evaporator coils. Meanwhile, help prevent these issues where possible with regular maintenance.

Air conditioner not cooling at home for couple on couch

In summary, an air conditioner not working is not much use to anyone.  It is not only an inconvenience but can also be life threating.  The impact of air conditioning on health is certainly underrated.

Many of the issues that stop air conditioner working stem from lack of AC servicing.  However, there are still many issues that can arise no matter how well you care for your air conditioning.

Whether you need air conditioning repair service or a just regular check-up, it is always recommended to call in an HVAC professional at least once a year.  Just like servicing your car, an air conditioner requires servicing on a routine basis.

Beat the heat and get ahead of the next heatwave; book air conditioning repair service today.