Frequently Asked Questions

Q. My air conditioning unit isn't cooling. What's wrong with it?

A. Poor performance could be due to one or more factors:

• Low refrigerant - an air conditioning system requires a minimum amount of refrigerant to cool properly. If the refrigerant level is low, it will work less efficiently and will not cool well.
• Dirty condenser - the condenser is the heat exchanger which cools the hot high pressure refrigerant after it exits the compressor so that it can condense into a liquid. If the condenser is full of leaves, insects or other road debris, air flow through the unit may be impeded to the point where little cooling can take place. Cleaning the condenser should cure this problem.
• Condenser cooling fan not working - the condenser often has its own separate electric cooling fan. This fan should come on, and remain on, when the air conditioning system is operating. If the wiring, fan motor, or motor relay is defective, the fan may not work.
• Internal blockages - any type of debris, for example rust, in the system may block the tube or the metering valve through which refrigerant flows into the evaporator. This will cause a loss of cooling, and potentially cause damage to the compressor as the system probably relies on oil circulating with the refrigerant for lubrication.
• Air or moisture contamination - the refrigerant inside the system, which must remain free of moisture, can freeze and form ice that will cause blockages. Contamination can result from leaks in the system or failure to vacuum purge the system prior to recharging it with refrigerant.
• Other electrical or mechanical problems - these would include compressor wear, the compressor clutch failing to engage, metering valve failures, inoperative pressure switches, etc. Precise diagnosis will require a technician who has all the necessary tools and equipment, and who has been trained in this highly specialized process.

Q. Why do I need to get my air conditioning system checked?

A. How much do you rely on your air conditioning system in warm weather? Do you remember the feeling in summer of a warm stream of air coming out of your air vents?

With that in mind, you need your air conditioning system to be working at its optimum level of efficiency.

Whilst your air conditioning system is low maintenance, it is not maintenance free. It is quite common for people to turn off their air conditioning system throughout the winter months. However, in doing so, any condensation left in the pipework, together with the heat generated by the engine provides an ideal environment for bacteria and mould spores to develop.

This may be noticeable by unpleasant odours, or you may find you are affected by sore throats or allergic reactions.

The air conditioning system, like any mechanical system, requires routine servicing to maintain its effectiveness. The last thing you need is for the system to perform inadequately, draining your engine power, or to stop working completely, especially in warm weather.

Q. How can I get rid of smells and bacteria from my air conditioning system?

A. Fortunately, you can rid yourself of the problems caused by the unpleasant presence of mould and bacteria, courtesy of a simple air conditioning de-bug, which takes around 30 minutes and could be done "while-you-wait".

However, regardless of whether you use your air conditioning system over the winter months or not, we recommend you have a full air conditioning service on an annual basis.

This will ensure your whole air conditioning system is working effectively. Within this service your car will be tested for leaks within the system, this is particularly important since the oil lubricating the air conditioning compressor is suspended within the refrigerant gas. The refigerant gas will then be removed and filtered before returning it to the system and topping up where necessary, together with fresh oil.

Q. Why should the air conditioning system be used even during the winter months?

A. Using the air conditioning system during winter months will prevent the windows from misting inside the vehicle as the air is dehumidified, and regular use will help prevent oil seals drying out thus preventing refrigerant loss or compressor failure.

Q. How does the air conditioning system keep the car interior cool?

A. Most people think that an air conditioner simply adds cold air to the interior of the car. Actually, there is no such thing as cold; rather there is an absence of heat. The job of the air conditioner is to remove the heat and humidity that we find uncomfortable. A compressor circulates a liquid refrigerant, compressing the liquid into a hot, high pressure gas. This hot gas is then run through coils so the heat can be dissipated and condensed into a liquid. The liquid then goes through an expansion valve and evaporates to become a cold, low pressure gas. This cold gas then runs through a set of coils which allow the gas to absorb heat and, in so doing, cool the interior of the vehicle.

Q. Are there different types of refrigerant?

A. Yes, Isceon 49 or RS-24 (R12 was used up to October 2000 but its use is now banned) is used for vehicles manufactured up to 1993, later vehicles use R134a. Refrigerant gases must never be mixed or cross-contaminated.

A. Why is oil added to the system when the refrigerant has escaped?

A. When refrigerant escapes from the system oil is also lost, if this is not replaced the compressor will seize.

What should I do next?

Please contact Vehicle Air Conditioning on 07919 521999, or complete an on-line enquiry form, and we will be glad to arrange a suitable time to visit.