Why do I need to have my A/C system serviced?

All vehicle air conditioning systems will leak to some degree. The losses occur through refrigerant escaping through the pipe joints as a result of vibration and the ageing of rubber hoses and ‘O’ ring seals, as well as through the seal on the front of the compressor shaft.

How often should the A/C system be serviced?

Every 12 months should be sufficient. Sub Zero can provide a comprehensive list of all checks carried out and produce a report on the condition of the system.

Why does my fridge at home not need servicing every twelve months?

A domestic fridge has no rubber pipes and no seal on the front of the compressor shaft; all piping is copper therefore there is no leaking through pipe walls.

Is it true that the A/C system should be run often throughout the year?

Yes, this helps to keep the system well lubricated and leak tight.


Because the refrigerant actually carries the oil that lubricates the system, most importantly the compressor. It also keeps the seals and hoses moist, thus preventing them from drying out and cracking leading to leaks.

Why is looking after the compressor so critical?

This is the main component in the A/C system, replacements typically cost £300 – £700, plus labour costs to remove and replace. Also it usually follows that a seized compressor will result in other components getting damaged in the process.

What's involved in a service?

We measure the pressures in the system, check quality of refrigerant present and check all functions. Then we recover the refrigerant and vacuum the system down to a very low pressure to remove any moisture that might be present. We then Re-Charge (Re-Gas) with virgin refrigerant or the customers own recycled refrigerant and replace any lubricant that was recovered with the refrigerant.

Why can't I service the system myself?

This is difficult not only because specialist equipment is needed but most importantly the refrigerant present in the system must be recovered. It is ILLEGAL to vent the refrigerant into the environment. The system is also under high pressure and needs pulling into a deep vacuum to remove any moisture. The refrigerants themselves have a very low boiling point and will cause freeze burns if they come into contact with skin or eye tissue.

Why put Ultra Violet (UV) dye in the system?

The UV dye shows up under a bright UV light source. So any leaks present in the system can be easily identified either during fault finding or if future leaks were to develop.

Why use Nitrogen for leak testing?

We use Oxygen Free Nitrogen (OFN) for leak testing. It would be illegal to re-gas a system to use the refrigerant as a means of leak detection. The pure form of Nitrogen is a naturally occurring gas in the air that we breath and so is safe and legal to use. The Nitrogen is inserted into the system under high pressure thus simulating a system in operation and revealing any leaks in the system.

Why should my gas be analysed?

Our gas analyser can reveal whether or not your gas is the correct type for your vehicle aircon system and whether or not it is contaminated which would strongly suggest a leak in the system. The wrong type of refrigerant could also bring about the premature failure of the compressor as it may not be able to carry the essential lubrication around the system.

Important Information:
It has been known for systems to be Re-Charged using Hydrocarbon based  refrigerants e.g. propane or methane mixtures. This means you could be driving around with a potentially lethal mix of gases in your system which in the event of an accident/collision could lead to the risk of an explosion.

If you suspect your system may have been recharged with such a mixture, why not have Sub Zero run a check for you.