Ask the Chemist:
How to quickly check acid levels in compressor lubricant

1) How does an acid test for air conditioning and refrigeration lubricants work?

The purpose of acid tests is to check and measure the presence of acidity in a refrigeration or air conditioning system. More precisely, the check is performed on the compressor lubricant.

These tests can be carried out by dedicated laboratories, which would inevitably lead to increased costs and would require more time, or directly by HVAC technicians, through easy-to-use acid test kits that offer a much faster yet accurate result.

2) Why is it important to perform an acid test on the compressor lubricant of an AC/R system?

It is essential to keep acid levels under control, as it can cause irreversible consequences and damages to the entire system.

If left untreated, acidity not only leads to obvious losses in efficiency with increased component wear, failures, and premature breakdowns but also contributes to carrying more moisture and unwanted products into the system. These are the result of moisture degradation of the lubricant, and they can potentially react with the acidity already in the system, creating additional acid compounds that get added to the total acidity. The acidity, therefore, tends to feed itself by keeping reacting with system materials and the refrigerant. These reactions are called catalytic and tend to increase exponentially.

3) Would you mind telling us something more about the acid tests mentioned before and that are mainly used by HVAC technicians to get a quick result?

Because of the above reasons, performing acid tests regularly is highly recommended. For this reason, HVAC technicians need a fast, handy, and easy-to-use tool. To meet the needs of the market, Errecom has developed Acid-Test. Its chemical elements react with the acidity of the lubricant, changing colour and indicating the level of acidity found. Simply place a few mL of refrigeration lubricant in one of the 4 supplied tests, shake for a few seconds and watch the colour change. The result is immediate, accurate, and easy to understand: purple indicates no acidity; green identifies moderate acidity; yellow indicates high acidity.

4) How often do you recommend performing the acid test?

It depends on the workload of the system. The higher it is, the more frequently the AC/R system will need to be checked and maintained.

I would suggest checking the acidity status both before and after an intervention to ensure that no acidic components have been accidentally introduced into the system during the process.

If the system is used under standard conditions, I would recommend checking the acidity level once a year.

5) We know that one of the characteristics that determine the quality of a lubricant is its acidity. Is this correct?

Of course it is! High-quality lubricants are characterised by low moisture and acidity levels for all the reasons explained before. However, this is not the only feature to consider. The quality of an AC/R lubricant also depends on its basic and specific properties. Chemical stability, for instance, is essential to prevent the lubricant from chemically reacting with system components or the refrigerant. Besides, thermal stability prevents the breakdown of chemical bonds that could otherwise lead to problematic reactions. High-quality lubricants must also have good freeze resistance and a high viscosity index, to maintain good lubrication properties at high temperatures and good fluidity at low temperatures.

6) Would you recommend Acid-Test as an effective method to determine the quality of a new lubricant before its insertion into the system?

Yes, Acid-Test is ideal both for preventive maintenance of the systems (aimed at monitoring the condition of the compressor lubricant), and to detect the presence of a too high acidity rate in a newly purchased lubricant.

We can therefore say that Acid-Test can be used by the technician as a fast and accurate method to analyse the quality of a lubricant, whether it is already circulating in the system or not yet.

7) What are the benefits of Acid-Test?

First of all, it is a universal test: unlike other products sold on the market, in fact, it works with any type of lubricant (POE, ABZ, PAO, PAG, PVE, Mineral). Moreover, Acid-Test is easy to use and provides a clear, quick, and sure result.