Air con servicing

It is harder to list cars that do not possess air conditioning than those with it but is the repair market oversaturated? Rob Marshall asks if either advancing your knowledge, or becoming a specialist for the first time, is worth the effort

As air conditioning (including climate control, its more sophisticated partner) is virtually universal, you might think it pointless to offer a repair service for the first time. Nissens concurs that garages who take the plunge may face intense competition but, as with any other speciality, new players that offer high-quality repairs will succeed. This claim rings true especially for air conditioning, because the systems are particularly intolerant of poorly-executed repairs. Therefore, Delphi advises that it is even more critical that garages keep-up abreast of both knowledge and equipment to offer a complete repair solution, as well as fitting high-quality parts. Nissens agrees that, while you can buy excellent and fully automated equipment, you will not be able to diagnose and service the system satisfactorily without knowing and understanding how it works. As Denso discovered that technician installation errors account for 99.9% of its compressor warranty claims being rejected, it underscores training's relevance. Knowledge, therefore, is power.

Clearly, many parts of a motorcar do not benefit from prolonged periods of inactivity and the air conditioning system is far from immune, because relatively few motorists realise its benefits during wintertime. Nissens advises that it is worth telling your customers to run the systems regularly, otherwise some costly components, such as the compressor, may suffer from inadequate lubrication. Primalec explains that cars that are not used regularly may be more prone to AC refrigerant leaks, because the elastomer seals in the system are not kept supple, an issue with which Denso also highlights. Delphi concludes that, where a system might have worked perfectly before the last lockdown, this does not guarantee that it will work now. Yet, switching it on, after a sustained period of inactivity, might be too much for the system’s compressor.

Aided by condensation, there is a risk of increased bacteria and mould build within the air vents/evaporator surface, while the car was laid-up. Delphi, therefore, predicts a high demand for air conditioning servicing over the coming months and garages should realise this not only as another opportunity to recoup potential income loses during 2020 but also to offer the best service to customers.

Clearly, much has happened globally, since AT looked into the air conditioning trade early last year. Many changes focus on the refrigerants and the phasing-out of R134a, which has a relatively high Global Warming Potential (GWP), compared to R1234yf. It seems as though the EU is continuing with restricting R134a supplies, with a view of phasing it out completely, but this decision may be undermined by the increasing number of illegal Chinese HFC refrigerants entering the market. Denso explained that the fight against these dubious quality gases is one of the European Anti-Fraud Office's operational priorities.

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Denso also highlighted a recent Dutch project, to adapt an R134a system to work with R1234yf. It concluded that, while feasible, all of the main components need changing, including the compressor and condenser. Therefore, the conversion is viable only if the circuit requires extensive repair and the customer is willing to fund the work. Yet, Primalec reminds garages to appreciate that R1234yf is a very different refrigerant to the R134a, especially as their PAG oils are incompatible. Should you use the incorrect lubricant, therefore, you are likely to cause serious damage to the compressor.

Having an appreciation for basic air conditioning theory is only part of the story. This is especially true for diagnostics. Delphi highlights that its DS diagnostic tool gives the garage the capability to perform in-depth diagnostics of the air conditioning system. While accessing the HVAC ECU for fault codes and obtaining live data from the various sensors are

Nissens predicts that Heating, Ventilation and Air Conditioning (HVAC) systems that include heat pumps will become more popular, due to their high efficiency. While we shall look at their operation in greater detail shortly, their main advantage is that they can act in a similar way to an air conditioner but in reverse. The system can absorb heat from outside the car and compress the refrigerant to warm it even more. This heat can then be delivered to the cabin. The HVAC heat pump combines both heating and cooling systems within a single circuit. Therefore, dependent on the selected working mode, it can serve as a heater and chiller for both interior and the high-voltage battery pack. As you can see from the picture of a circuit from an Audi e-tron, heat pumps add considerably more complication and will offer considerable potential for garages looking at post-traditional combustion engine repairs. AT plans to probe these systems in greater depth in a future issue. As air conditioning systems are evolving continually, take advantage of training to update your knowhow. Delphi offers a two-day air conditioning course, including F-Gas certification. This includes a detailed look at the system and component operations and how to carry-out component servicing and repairs. Additionally, it adds extra tuition on climate control systems, how high voltage hybrid systems differ from belt-driven systems, along with practical recovery, charging, recycling and leak detection methods, all combined with an assessment for EC307/2008 F-gas legislation. For independent garages, Delphi also highlights its technical hotline support and vehicle technical information software. Additionally, a range of how-to videos are available on delphiautoparts. com, giving technicians best practice advice on how to replace key components.

Nissens also reminds readers that it has offered the independent aftermarket repairer high-level technical expertise for many years through the Nissens' Training Concept. This knowledge-sharing platform offers flexible, high-quality training that is available as personal online sessions, self-learning, or live audience training. To learn more, visit nissens.com/ntc

useful, the DS tool allows you to not only activate components but also perform system post-replacement resets. Delphi underlines the Vehicle Technical Information (VTI) function, integrated into its DS software, which includes repair data, drawings and procedures for all makes and models. It reasons that having access to such reliable data quickly provides technicians with the confidence to perform the repair in-house and reduces non-billable hours, thus improving workshop efficiency.

Denso reminds us that, since all new passenger cars sold in the EU from 2017, had their air conditioning systems charged with R1234yf at the factory, most independent garages have now embraced the refrigerant. In the short-term, workshops should prepare to service and repair systems fitted to EVs and high-voltage hybrids. Aside from the safety risks posed to untrained technicians, Delphi highlights that they use special polyolester (POE) type oils, with high dielectric (insulative) properties to protect the compressor's electrical windings. Yet, cross-contamination, caused mainly by poor workshop practice, must be avoided. Only one percent of PAG in a system designed for POE oil can reduce the insulation resistance of the compressor significantly. The result can be so serious, not only can the system shut down but Delphi also reports that the technician could receive a potentially lethal electric shock. This contamination risk can be mitigated by using the correct oil and using a recharging machine that is designed to work on both conventional and hybrid systems. The alternative is to invest in a separate machine, designated solely for high-voltage air conditioning circuits.

Nissens reminds us that it is the vehicles that define the service demands, so we should expect to see more gases and more advanced systems in the future. It seems that the move to

CO2-based (R744) refrigerants continue, despite their being no pertinent updates over the last year. EVs especially are expanding the air conditioning system's remit as a means of controlling high voltage battery pack temperatures. Primalec points-out that, as EV batteries work most efficiently between 15-30 degrees Celsius, efficient thermal management is crucial to their performance. Denso says that, because heat-pump systems can cool and warm not only the interior but also the battery, they also require additional knowledge about how they are repaired and maintained. While the EV and plug-in hybrid car parc is growing, the numbers on our roads remain relatively small, and so an all-makes garage may have to make a decision about whether (or not) to postpone investments in this area until there is a more convincing business case. Conversely, this is a vital area of investment for an independent hybrid and electric vehicle specialist. While many readers know that disinfecting the HVAC ventilation circuit and replacing the cabin filter has health benefits, many garages have invested in ozoneproducing sanitising machines since the pandemic began. A problem with ozone is that it can have a detrimental effect on interior plastics and rubbers, causing them to degrade prematurely. Replacement of trim, especially on older cars, can be either impossible, or expensive, especially on cherished vehicles. We queried Primalec on this topic, specifically about its Airco Shield Purifier, who responded:

"Ozone, generated by our Purifiers, is not harmful to plastics or rubbers. Ozone in urban air will have a much more harmful effect. However, there are some ozone generators on the market which emit excessive ozone, and this can be a hazard unless carefully controlled."

http://polymerdatabase.com/polymer%20chemistry/ Ozone.html

www.noai.org/does-ozone-damage-rubber

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