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In the heat of summer, cold AC in the car is essential. So when it’s not working as it should you tend to notice. Diagnosing a problem with a car air conditioning system can be a tricky business and it involves some extra understanding of how the system works. We’ve put together this AC 101 to provide an overview of the ins and outs of your vehicle AC system.

So how exactly does a car’s AC system work?

Air conditioning was first introduced in 1939 and it has worked pretty much the same way for its entire existence. In most basic terms your car’s AC system is just a weirdly laid out fridge designed to move heat from inside of your car to the outside. This means it not only cools the air down, but also reduces the moisture content, or humidity.

All car air conditioning systems are sealed systems with a high-pressure side and low-pressure side. The fluid that is used in the system is called refrigerant. Your car’s AC is made up of 3 key components, plus a few other parts to keep the system running smoothly.

Compressor: 
The compressor is the workhorse of the car air conditioning system. When the aircon system is turned on, the compressor pumps refrigerant vapour under high pressure to the condenser.
Condenser: 
The condenser is a device used to change the high-pressure refrigerant vapour to a liquid. The vapour is condensed to a liquid because of the high pressure that is driving it in, and this generates heat. The heat is then in turn removed from the condenser by air flowing through the condenser on the outside.
Receiver: 
The now liquid refrigerant moves to the receiver-dryer. This acts as a filter for the liquid refrigerant, removing any moisture and other containments that may have leaked into the refrigerant.
Expansion Valve: 
The pressurised refrigerant flows from the receiver-drier to the expansion valve. The valve removes pressure from the liquid refrigerant so that it can expand and become refrigerant vapour in the evaporator.
Evaporator: 
As the cold low-pressure refrigerant is passed through the evaporator, it vaporises and absorbs heat from the air in the passenger compartment. The blower fan inside the passenger compartment pushes air over the outside of the evaporator, so cold air is circulated inside the car.
Compressor:
The compressor then draws in the low-pressure refrigerant vapour to start another refrigeration cycle. The refrigeration cycle then runs continuously and is regulated by the setting of the expansion valve.

Why get your AC serviced regularly?

The air conditioning system in your car is made up of many different components, so regular maintenance of your car’s AC system is one of the best preventative measures you can take. Quite often, an AC service can identify minor issues prior to them causing major damage to a system. We recommend getting your car air conditioning serviced every two years to keep your system at peak performance.

What we do during an AC service:

Contrary to what many believe there is much more involved in an AC service than just a simple regas. During our Air Conditioning Service, we:

  • Check the Temperature of the AC
  • Check A/C system pressure levels
  • Inspect for leaks (if UV dye is present)
  • Recover all gas from the system
  • Pressure Test with Nitrogen
  • Evacuate System
  • Re-gas system with R134a and UV dye.

In addition to the standard AC service, we can also provide replacement cabin/pollen filters and antibacterial treatments.

Why can’t we just top up the system if its low on gas?

The gas that is inside a car’s AC system is known as R134a. R134a is an ozone depleting substance and synthetic greenhouse gas and if released into the atmosphere, it can damage the ozone layer and have a negative impact on the environment. If your system is leaking, putting more gas in the system is only going to release more harmful refrigerant into the atmosphere or worse into the cabin of the vehicle. As ARCTick Licenced technicians we are required by law to fully inspect and repair any leaks prior to putting any refrigerant back in the system.

Common AC Problems:

Low gas is a common reason for an AC system to not operate as it should. The air conditioning system in your car is meant to be a completely sealed unit, so in most cases, if the system is low on gas there is a leak or fault somewhere in the system. Some of the other most common issues people have with their car’s AC are:

  • AC is not blowing cold air
  • AC is blowing hot air
  • Odour coming from vents
  • Fluid leaking
  • Weak airflow, low or uneven air pressure
  • Clunking or rattling noise when the AC is switched on

There are a number of different causes for these issues including damaged components, leaking hoses, electrical faults, blocked valves and many, many more.

Watch our video below for some of the AC checks you can do at home.

Unfortunately, AC issues are not always a cut and dry diagnosis. If your AC system is not performing as it should be, your best bet is to get your car inspected by a qualified auto-electrician as soon as possible. At Accelerate Auto Electrics we specialise in all types of vehicle air conditioning systems so we can repair just about every type of system you can think of.

If you have any other concerns, issues or questions about your car’s AC, feel free to give one of our friendly techs a call on (07) 5479 6622 or send us an email to [email protected]