FAQ/Advice
On this page you will find various pieces of information about air conditioning and how keep it working efficiently and effectively.
Questions
- Why do air conditioning systems need to be services?
- Why is it necessaey to replace the interior filter once a year or every 15,000km?
- Why does the filter/dryer have to be replaced?
- What happens during an air conditioning service?
- Where does the musty smell inside the vehicle come from?
- Why do my windows fog? How can i prevent this?
- How can refrigerant escape from the air conditioning system when it is a closed system?
- How can I use my air conditioning system as effectively as possible?
- How do i notice that there is something wrong with my air conditioning system?
1 - Why do air conditioning systems need to be services?
- Because up to 10% if the refrigerant is lost every year.
- Because, otherwise, the compressor oil supply is no longer guaranteed.
- Because humidity in the system can cause expensive repairs.
In contrast to what some vehicle manufacturers say, vehicle air conditioning systems must be serviced regularly. Every year, up to 10% of the refrigerant is lost from the system naturally through hoses and connection elements. This means that the cooling capacity is noticeably reduced after only three years. In addition, the refrigerant that circulates through the air conditioning system serves as a carrier medium for oil that is also in the system.
The air conditioning compressor requires this oil as a lubricant. If there is not enough refrigerant in the system the compressor may no longer be sufficiently lubricated. This can lead to compressor failure. The necessary repairs can quickly run up a bill of £700+.
This can be avoided if the air conditioning system is checked once a year. In addition, the refrigerant absorbs humidity from the outside via the hoses. Part of this humidity can be trapped by the dryer in the air conditioning system. The saturation point, however, has been reached after 2 years of operation. If the dryer is not replaced regularly, the high water volume in the system will lead to corrosion. Increased wear and mechanical damage to system components are bound to follow. The expansion valve could also ice up. This can lead to considerable problems even up to complete failure of the air conditioning system. High repair costs can be avoided by replacing the dryer regularly.
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2 - Why is it necessaey to replace the interior filter once a year or every 15,000km?
- Since the air flow through the interior filter is reduced the more it is used, regular replacement is necessary and prescribed by the vehicle manufacturers.
- A blocked interior filter can destroy the fan motor.
- Fogged windows are often caused by a soiled filter.
- Unpleasant smells can also originate from the interior filter.
The interior filter is usually made of micro-fleece material that filters dust, dirt and pollen out of the air. In the case of an active carbon interior filter, gaseous pollutants (hydrocarbon compounds, ozone) are also filtered out. When you consider that up to 300 cubic metres of outside air flow though the filter per hour, you can imagine that the 'saturation point' has been reached after approx 1 year or 15,000km and that the filter needs replacing. If this doesn't happen, air throughput will be reduced. This puts more strain on the interior fan motor and can destroy it in exteme cases due to overheating.
A further result of a soiled filter is that the windows fog up due to humid air inside the vehicle. In time, the dirst particles trapped by the filter react with the air humidity. When the filter is too old, this can also lead to unpleasant smells developing.
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3 - Why does the filter/dryer have to be replaced?
- The filter/dryer removes humidity and dirt particles from the air conditioning system to protect it from damage and guarantee optimum cooling performance.
Part of the humidity from the air conditioning system can be trapped by the filter/dryer, which can also be known as an accumulator depending on the system. The saturation point as been reached after approx. 2 yrs of operation. If the dryer is not replaced regularly, the high water volume in the system will lead to corrosion. Increased wear and mechanical damage to system components are bound to follow. The expansion valve could also ice up. This can lead to considerable problems up to complete failure of the air conditioning system.
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4 - What happens during an air conditioning service?
- The refrigerant is discharged.
- The dryer is replaced (every 2 years).
- The system is evacuated with a high vacuum pump to remove moisture.
- Visual inspection of all components, monitoring of connection and drive elements as well as wiring and operating elements.
- The system is recharged with the correct amount of refrigerant specified by the manufacturer.
- The interior filter is checked/replaced (annually or every 15,000km)
- A functional and leak test is carried out on the whole system.
- The results of the individual test steps are documented.
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5 - Where does the musty smell inside the vehicle come from?
- The cause can be an old interior filter and/or a soiled dryer/evaporator.
In time, the dirt particles trapped by the filter react with the air humidity. When the filter is too old, this can lead to unpleasant smells developing. Bacteria, fungus and other micro-organisms nesting in the evaporator can create musty smells and provoke allergic reactions. Regular filter replacement and regular disinfection of the evaporator will eliminate this problem or prevent it occuring in the first place.
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6 - Why do my windows fog? How can i prevent this?
- Fogging on the windows is nothing more that humidity in the air condensing on them - specific use of the air conditioning system can help here.
In the cold, wet season, the air is generally damp, and we bring more humidity into the vehicle again and again on our clothes, wet shoes, and jackets. This effect is increased even more by human breath. And have a good look at your foot mat! There is often a 'lake' here, favouring even more window fogging. The air conditioning system dries the air in the vehicle interior, clearing the windows quickly. They clear even quicker if the circulation mode is selected first.
This can be done in next to no time:
- Switch the air conditioning on.
- Direct the air flow only onto the windscreen.
- Press the recirculation button (in some vehicles this is not possible in combination with point 3 - continue with point 4)
- Set ventilation and heating to maximum
(switch recirculation mode off again after a short time and set the ventilation switch some medium level)
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7 - How can refrigerant escape from the air conditioning system when it is a closed system?
- Through hoses and system component connections.
A small amount of refrigerent can escape due to 'natural seepage' through the hoses used in the system and the seals of the individual system components. This can be up to 10% of the total refrigerant volume per year. A 100% sealed system is not possible due to the requirements placed on the system in vehicles (flexible lines, material selection).
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8 - How can I use my air conditioning system as effectively as possible?
IN THE SUMMER
- Park in the shade.
- Open the doors for a short time before starting your journey.
- Set the air conditioning and ventilation to maximum at the start of a journey.
- Drive with the windows/sunroof open for the first few minutes.
- The interior temperature should not fall below 22 degrees C.
If possible, park your vehicle in the shade on sunny days. Otherwise the temperature inside the vehicle can rise to up to 60 degrees C. To get rid of standing heat in the vehicle, open the doors briefly before starting your journey. To make things pleasantly cool as quickly as possible, we recommend switching the air conditioning to maximum cooling and the fan speed to maximum. The air stream does not have to be directed directly at the passengers. Brief use of the recirculation mode speeds up the cool down. Opening the windows and sunroof during the first few minutes has the effect of exchanging the air more rapidly, thus cooling the interior quicker. 'Draughts' must be avoided. The interior temperature should not fall below 22 degrees due to health considerations.
IN THE WINTER
- Switch the air conditioning on
- Direct the air flow only onto the windscreen
- Press the recirculation button (in some vehicles this is not possible in the combination with point 2 - continue with point 4)
- Set ventilation and heating to maximum
To warm and dry the air and clear the fogged windows as quickly as possible, the air conditioning system should be switched on before you begin your journey and the air flow directed at the windscreen. To prevent even more damp air entering the passenger compartment, recirculation mode should be chosen temporarily. We recommend setting fan speed to the highest level and the heating to maximum. Recirculation mode must be switched off again after a short time.
In most cases the medium level is sufficient once the fogging has been cleared from the windows.
The air conditioning system can then be switched off.
Note: models on some manufacturers switch the air conditioning system off automatically when the outside temperature falls below approx 4 degree C. Recirculation mode with the air conditioning system switched on and the air flow directed only at the windscreen is not possible on some vehicles.
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9 - How do i notice that there is something wrong with my air conditioning system?
- Poor cooling performance
- Increased fuel consumption
- Noise
- Fogged windows
- Development of unpleasant smells
The points mentioned above can be seen as signs that the air conditioning system has not been serviced properly or is not functioning correctly. Too little refrigerant can be the reason for poor cooling performance (refer also to "Why do air conditioning systems need to be serviced"). Increased fuel consumption can be caused by the air conditioning compressor being switched on too frequently and for too long.
Noises that can only be heard when the air conditioning is switched on are usually caused by the compressor or the expansion valve. Permanently fogged windows is often a sign for a soiled interior filter (refer also to "Why do my windows fog"). Musty smells can be caused by bacteria or fungus nesting in the evaporator. An old interior filter could also be the cause. To avoid follow-on damage, the air conditioning system should be checked by an expert without delay.
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