Today our R&D manager, Dr. Paolo Mattavelli, will answer questions about another problem that can occur in AC/R ...
Ask the Chemist: acidity inside an air conditioning and refrigeration system
The column “Ask the chemist” returns. Today our R&D manager, Dr. Paolo Mattavelli, will answer questions about another problem that can occur in AC/R and A/C car systems: the accumulation of acidity.
Reading Time: 5 min
- Can you describe the acidity problem in AC/R and A/C car systems?
The acidity in the system attacks its metal structure, causing oxidation and corrosion of various kinds. These can lead to several problems: pipes and exchangers perforation, windings burn out, impairment of moving parts’ work and production of stray metal oxide particles in the system. Furthermore, acidity accelerates the decay of the other chemical components, such as refrigerant gases and lubricant, favouring a further formation of moisture and consequent acidity. - Why does acidity form?
Acidity in an AC/R system may be generated by the natural decomposition of the refrigerant gases and lubricants in use: these derivatives can react with the moisture normally present in the AC/R system to form organic, carbonic, hydrochloric and hydrofluoric acids. - Is acidity a natural phenomenon or is it unusual?
It is a phenomenon that must be kept under control with proper maintenance. - What are the consequences of acidity in an AC/R system?
The acids are very aggressive towards metal and they can cause leaks formation windings’ and compressor’s burning, valves blockage and the formation of free metal oxide particles wandering around the system. In the most serious cases the acidity can lead to compressor failure. - What are the consequences of acidity in an A/C car system?
The acidity in an A/C car system involves the same problems that can be found in AC/R systems, including the formation of leaks, valve blockage and the formation of free metal oxide particles wandering around the system. - How do I know if there’s any acidity in the system?
Some systems are equipped with a sensor or a lens that detects the presence of acidity. It can also be quickly detected by taking small portions of lubricant and carrying out a specific test, using Acid-Test, which we have developed specifically to verify the presence of acidity in the AC/R and A/C car system. - How do you solve the acidity problem?
The acidity problem must be tackled mainly through the use of anti-acid additives. Acidity is generated primarily by moisture: so, it’s necessary to keep the level of the latter under control. The action aimed at reducing the oxides of the system components also has a strong impact on the formation of acidity. Therefore, it is important to maintain an adequate charge of anti-oxidant and anti-corrosive additives of the chosen lubricant. Finally, it is important to avoid the formation of deposits: by this term we mean the sediment of certain fractions of the lubricant in the system due to the “Oil Fouling” phenomenon. These fractions become the place of formation and propagation of the damage caused by acidity. - Which product do you recommend using? And why?
I recommend using No-Acid Ultra, acid neutralizing additive for air conditioning and refrigeration systems. It’s the ideal product because it completely eliminates acidity residues in the lubricant and refrigerant gas of AC/R systems and reduces the level of humidity. Secondly, it increases the effectiveness of the compressor lubricant without causing chemical changes. Furthermore, it extends the life of the compressor and reduces friction inside it, reducing vibration and noise. In addition, No-Acid Ultra reduces system maintenance costs and CO2 emissions and its action is permanent over time.Finally, it is compatible with all refrigerant gases, including CO2 except R717 (ammonia) and is suitable for all types of air conditioning and refrigeration systems (A/C AUTO and AC/R). - Is it possible to avoid the formation of acidity? If so, how?
It is possible by selecting quality refrigerant gases, lubricants and additives that support their stability. The acidity formation can be avoided by keeping oxidation and moisture level under control through a good additivation and a careful maintenance of the dehydrating filter.In addition, when designing the system, it is essential to avoid the accumulation of electrical charges by setting up suitable discharge systems. For safety, it is advisable to prevent the problem by inserting a dose of anti-acidity product into the system to prevent its formation right from the start to prevent catalytic formation. - Do you have any advice for our readers?
Yes, I do. First of all, always carry out the specific maintenance plan. In case of compressor burn out, it is imperative to thoroughly flush the system and use anti-acid products to protect the new refrigerant and lubricant gas. Finally, I highly discourage you using lubricants with already high acidity rates for the new product.
