Air conditioning, (or AC, A/C, air con) is the process of removing
heat and moisture from the interior of a vehicle to improve the comfort of
occupants. This process is most commonly used to achieve a more comfortable
Recharging the air con system involves removing the existing refrigerant and any traces of moisture from the system and replacing with fresh refrigerant.
Using an automatic air con servicing machine, two hoses are
attached to the air con system under the bonnet – one to the high-pressure connection,
the other to the low-pressure connection. The first thing to be done is a
pressure test to find out just how much gas has been lost. If the pressure test
result shows little or no gas remains in the system the recharge operation is
stopped as this is an indication of a more serious issue such as a potential
If no faults are found, the machine sucks out the old refrigerant along with any impurities from the air con unit using a specialist vacuum pump. Then fresh gas and lubricant is pumped back into the air con system to the volume and type recommended by the vehicle manufacturer.
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Vehicle Air Conditioning - Everything you need to know Questions
How does air conditioning work in a car?
Inside a vehicles air conditioning system is a compressor which pumps the refrigerant gas, at high pressure around the air conditioning system. When the ‘air con' is switched on, the gas travels to a condenser where fresh air from outside the vehicle passes over it and the temperature of the gas drops quickly causing the refrigerant to liquefy. The liquified refrigerant then goes to a drier which removes impurities before reaching a thermal expansion valve which allows the driver to control the temperature in the car by limiting the liquid flow. After this process, the liquid is turned back into vapour as it travels through evaporation coils and is then blown into the cabin as cool air. At the same time, the refrigerant, which has returned to a gas, travels back to the compressor to start the process all over again.
Why does air con stop working?
The refrigerant gas found in your air conditioning unit is critical to the A/C system working properly. It is this refrigerant that flows around the system and provides the cold air in your cabin. However, as a result of this process which involves continually shifting states from gas, to liquid and back to gas again, some of the gas escapes through the system each year. Less gas means less cool air so refilling every few years will keep your air con working in tip top condition. Of course, there are other reasons why air con stops working but low refrigerant is the most common and the easiest to fix. If after a re-gas your air con is still blowing warm, it probably means there is a crack somewhere in the pipes of the air con system and the refrigerant is escaping.
Is air con part of my mot or service?
No, your MOT (Ministry of Transport test) ensures the vehicle is safe to drive as per DVSA guidelines. As air conditioning is not classed as critical component to the safe running of the vehicle, your MOT tester will not check the working condition of an air con system. Something else to consider, air conditioning systems are not included in the standard service schedule set out by the vehicle manufacturer. Many manufacturers provide a separate air con service schedule which will recommend a re-gas of the system, on average, every 2 years.
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How quickly does air con take to get to work once recharged?
With the air con recharged with new gas, you should be able to notice a temperature change almost immediately when the air conditioning is switched on.
How often should you recharge your air con?
Most vehicle manufacturers recommend an air con system is re-gassed every two years, irrespective of whether you use your car's air con a lot or hardly ever at all. This is because the air con refrigerant gas will continue to permeate through the system over time. An air con service every two years will keep the gas topped up and the system lubricated allowing you to always have a cool blast of conditioned air ready when you need it most.
How long does an air con recharge take?
The process takes approximately 45 minutes to completely remove the old gas and refill with fresh refrigerant. Having your air con system serviced by us, you can have your air con recharged while you wait and take advantage of our free WiFi and hot drinks.
Why recharge your car air con?
Apart from the obvious one being to keep you and your passengers cool on journeys in hot, there are many reasons to get your air conditioning recharged & in good overall condition. One reason that may surprise you is to get the most out of your tank of fuel as recharging your air conditioning increases your vehicles fuel efficiency. The reason behind this is because when your air con refrigerant is low, the air conditioning system struggles to cool the air and in turn makes the system work harder to try and produce cold air. This extra, prolonged, work uses more fuel. Keeping you air con recharged regularly means you won't have to pay out for expensive air con parts and repairs later in future. This is because the refrigerant used in your air con system is extremely cold and has the added benefit of cooling down the air con compressor. If the refrigerant is low, or non-existent in the system, , the compressor would get dangerously hot and would cause it to fail. Using Air conditioning isn't just for the hotter days either, it also helps you on cold winter days. Turn on your A/C when demisting your windscreen on a cold & frosty day will be achieved far quicker as I the air con system produces dry warm air to rapidly clear your view. Another benefit of using air con in the colder winter months of the year ensures the system doesn't seize up and will continue to work effectively when the temperature starts to warm again.
Still not sure?Call our Vehicle Air Conditioning - Everything you need to know specialists
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