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Car Air Conditioning faults

All You Need to Know About Your Car’s Air Conditioning

The UK seems to be enjoying it’s fair share of great weather recently, and there’s nothing worse than turning on the air conditioning only to be blasted with hot air. When that happens to you you’ll know that you’re in for a pretty sticky journey.

At Fergies we’re keen to keep you cool and comfortable whilst you’re on the road, which is why we’ve written this article that covers all you’ll need to know about your car’s air con system.

Why Do You Need An Air Con Recharge

Whilst your car’s air conditioning system is a sealed system, a vehicle is a harsh environment for it to operate in. A car’s A/C system uses rubber hoses to complement the fixed aluminium pipes. This results in a natural loss of refrigerant (commonly termed “gas”) which requires replacing over time. Without the correct quantity of refrigerant, your air conditioning system cannot remove the heat from the vehicle cabin.

There are also financial benefits to servicing your car A/C system. The system will not operate where the refrigerant is too low. In such scenarios extended periods of inactivity can lead to component malfunction that would not have occurred had the system been operated year round. It’s the classic “prevention is better than cure” situation.

How Does Your Car Air Conditioning Work?

My inner geek loves the science behind this system. Here are the steps required to cool your car.

  1. Refrigerant is transported around the system by your compressor.
  2. Liquid refrigerant passes through the expansion valve and boils (turns to a gas) as the cabin air is passed over the evaporator.
  3. As the liquid refrigerant boils it absorbs the heat from the cabin into the refrigerant. Without sufficient refrigerant, the heat from the cabin cannot be absorbed.
  4. The refrigerant gas is drawn into the compressor. The compressor raises the pressure and temperature of the refrigerant.
  5. The gas is now passed through the condenser, ambient air is blown over the condenser by your condenser fan.
  6. The heat is drawn out of the refrigerant and into the ambient air.
  7. Voila. Your air conditioning system has now moved the heat from the cabin to the outside of the vehicle and cooled the air in the cabin as part of the process.

This science is just so cool. Excuse the pun 🙂

Is Air Con checked as part of the MOT or Service?

Air Conditioning is not checked as part of the MOT, and most manufacturers don’t include air con as part of their service schedule and have an additional Air Conditioning service requirement.

At Fergies we’d advise that you have an A/C system check every 12 months, and serviced at least every 24 months to ensure that the system remains in good condition and keeps you cool when you need it most.

Why does your air conditioning stop working?

The most common cause of your air conditioning system not working is a lack of refrigerant (gas). Without the correct quantity in the system, the heat cannot be removed from the cabin.

The refrigerant leaks through a natural loss or system fault. A natural loss of refrigerant is one of the easiest problems to rectify, replacing this and can return your system to full health in many instances.

How is the refrigerant replaced? What’s a Re-Gas?

If we check your car’s air conditioning system and it’s found to be low on refrigerant here are the steps we’ll undertake to replace the A/C gas.

  1. Performance test carried out to discover the current system status. We inspect the temperature differential between the cabin and ambient air.
  2. Refrigerant removed from the system, weighed and compared to the specific quantity that your car requires.
  3. A vacuum leak check is carried out.
  4. A pressure leak check is carried out. Some faults cannot be found with a vacuum check.
  5. The system is evacuated using a specialist vacuum pump to remove any moisture from inside the A/C system.
  6. Dye is added to aid in future leak detection.
  7. Oil is added where required.
  8. The correct quantity of refrigerant is weighed into the system.
  9. A performance check is completed to ensure your car air conditioning system can cool the cabin sufficiently.

The re gas process is a common occurrence, and we complete many of these in the warmer months. It’s the most common A/C service we offer. But there’s some additional attention that your vehicle may require.

Air Con Re-Gas VS Air Con Service?

Whilst an A/C re-gas does exactly what it says on the tin, there are many other components in your car’s air conditioning system that require preventative maintenance to ensure your air conditioning works when you need it the most.

Here are a few of the common items carried out on an air con service to ensure your cabin remains cool and free of nasty odours.

  1. A/C condenser fan inspected for correct operation.
  2. A/C condenser cleaned of leaves and debris to enable effective heat exchange.
  3. Compressor drive belt inspected and condition reported.
  4. Under bonnet A/C pipes inspected for security.
  5. Refrigerant receiver dryer or Accumulator replaced.
  6. Pollen filter inspected/replaced to protect vehicle occupants from pollutants.
  7. A/C debug treatment to decontaminate your system and kill bacteria that builds up in your cabin vents.

Having these items checked every 24 months and the system re gassed will ensure the necessary preventative maintenance has been completed. This minimises the cost of expensive system faults caused by lack of inspection.  

What can you do to keep your A/C system free from faults?

It’s a common misconception that car air conditioning should only be used in warm weather. The most obvious benefit of using your A/C system year round is that it has the capability to dehumidify the air in the cabin.

This will not only clear misty windows faster in cooler weather but will keep your A/C compressor working. A small work out for your compressor on a regular basis means it stays healthy through the winter and ready to leap into action in the spring.

So… you’re now a car air conditioning guru, but what to do if yours isn’t working?

Quite simply give us a call at Fergies. We have an intimate knowledge of these systems and know how to turn a hot and sweaty car into a cool and comfortable driving experience.

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