Brett Meads, vice president of VASA (Automotive Air conditioning, Electrical and Cooling Technicians of Australasia) and owner of Gympie Auto Air, discusses the importance of having a refrigerant identifier – and using it.
Diagnostic goal posts have moved a little recently, and while some in our industry have been challenged by this undesirable shift, of more concern is the fact that others in our game have actually been the cause.
This change in the diagnostic landscape has caught many of us out because for too long we have based our diagnostic detective routine on one tried and tested assumption that the stuff inside the AC system is refrigerant.
If you start your next HVAC diagnosis based on the premise that the gauge readings are measuring pure refrigerant, then you might be in for a long day. The occurrence of non-pure refrigerant within automotive systems is increasing at an alarming rate. How does the contamination occur? The introduction of alternative refrigerants to R12 meant that, over time, it would be impossible to keep refrigerants completely separate.
We have all seen evidence of cowboys topping up an R12 system with R134a or with one of the many blends, or the topping up of an R134a system with the latest 'one size fits all' hydrocarbon. Despite the problems arising from the resulting refrigerant cocktail, at least the refrigerant mixture was condensable in most AC systems.
Add to that the legislation introduced to prevent the emissions of synthetic greenhouse gases. In recent years our industry has been busy complying with the regulations by recovering the AC system contents. And we recovered the contents assuming the AC system contained pure refrigerant.
Sadly, however, too many technicians are recovering the AC system contents without knowing exactly what it is they are recovering. You can add to this the issue of poor work practices, including charge hoses not being purged correctly, sacrificial pressure testing charges being added to unknown systems, incorrect operation of recovery equipment, inadequate flushing procedures and poor or non-existent system evacuation.
The result is a recovery cylinder containing non-condensables, and that is a very real problem. And by non-condensables I mean air, the air we breathe. If you don't know it is there, air in an automotive AC system refrigerant circuit is a diagnostic nightmare. Air can make your compressor look lazy, have you looking for excess oil in the system, and have you blaming whatever flow device you can point your finger at.
The best case scenario is that an air laden system will present to your workshop with symptoms of poor performance, and as a result will challenge you diagnostically.
Of more concern is that it has caused the AC system to fail, usually culminating in compressor failure, and often compressor failure so severe that the refrigerant charge has been vented to the atmosphere. By far the worst outcome is when an air laden AC system is recovered during the course of repair or servicing, and the assumption made is that the system being recovered contains pure refrigerant when, in reality, it does not.
The recovered substance, a heady mixture of refrigerant and air, is recovered into a storage cylinder with the intention of using the contents of that cylinder to recharge an AC system at some point in the future. This is now more common than you might think thanks to the uptake of the all-in-one ‘recover, recycle and recharge’ AC machine of magic.
Without a refrigerant identifier, there is no way of knowing what was recovered from previous systems and is now swimming together in the same storage cylinder. There is no way of knowing unless every technician using the machine of magic used a refrigerant identifier on every AC system. As a result, the likelihood of the next refrigerant charge delivered by this machine to be pure refrigerant is almost nil.
And this is the point of the story: buy a refrigerant identifier. If you already have one, use it. Use it on every vehicle you work on. One air-laden AC system recovered into a storage cylinder can result in 15 or 20 contaminated recharged systems -it spreads like a virus. As professional technicians we do a good job stopping the refrigerant from entering the atmosphere. Now we need to do a good job stopping the atmosphere from entering the refrigerant.