CONTROLS AND INSTRUMENTATION
Service challenges for technicians
W
Richard Doran, managing director of Primalec talks leak detection. Safety:
e all know that the global HVACR industry is in a period of rapid change. The need to make systems ever
more energy efficient, alongside technological advances and legislation restricting the use of environmentally harmful refrigerants, are the key drivers of this change.
For many decades the refrigerant cycle was a relatively simple process, using only a handful of standard refrigerants. The past decade has brought us many challenges and a plethora of new refrigerants and control technologies. Developments such as these do require a fresh approach to service procedures in a number of respects. Here are some of the most important examples.
In its search for efficient and environmentally acceptable refrigerants, the industry has embraced new chemistry, as well as going back to some of the older natural refrigerants, such as hydrocarbons and ammonia, some of which present higher risk factors for engineers. High flammability in the case of hydrocarbons, and high toxicity in the case of ammonia refrigerants, require different approaches with regard to personal safety. These are challenges that must be recognised and dealt with. The very high pressures required in CO2
systems also impact on safety procedures.
Make sure that the technicians are properly trained for interventions on the refrigerant on which they are out to work. Personal protection
Documentation and training:
Proper documentation is not just good practice but is now essential. Knowing what refrigerant is in a given system or cylinder has also become much more important. This is true not only for safety reasons, but also for job pricing and for correct and safe equipment operation. Refrigerant identification can contribute to the documentary process, but is also a valuable and time saving tool, allowing engineers to determine both the identity and purity of what is in the system and in your increasingly expensive cylinders.
New refrigerants often owe their improved environmental credentials to their ability to break down faster in the atmosphere. However, that can also make them more prone to breakdown inside the acr system itself if, for example, the wrong procedures are followed or inappropriate compressor lubricants are used. Proper use and care of acr equipment is essential to reach and maintain the intended efficiency. In the past, a GS2 or GS3 mineral oil was good enough for all. In today’s challenging world, we are looking at various grades and formulations of polyolester lubricants, but also extreme performance polyalkylene glycols, PAO, PVE and who knows what else we will find in the future.
All these new refrigeration lubricants are much more hygroscopic than in the past. And with systems relying more and more on sensors and, for instance, electronic expansion systems, oil must be clean and with a neutral pH. In other words, proper vacuuming of a system is paramount. New types of vacuum gauges are more precise and can also quickly give indications of poor oil or minor leaks in system. Make sure that the vacuum gauge you have goes down
48 December 2017
may now even include such items as personal breathing apparatus, or having a defibrillator available.
www.acr-news.com
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