The concentrate of acid in refrigeration oil is expressed as an acid number in mg of KOH per gram of oil (milligrams of potassium hydroxide per gram of oil). The acid number is a measure of-the amount of hydroxide solution needed to neutralize the acid in the oil. The more acid there is in the oil, the more potassium hydroxide is needed to neutralize it and, so, the higher the acid number. In the phase III test, an acid number of 0.05 mg KOH per gram of oil has been set as the maximum acceptable acid concentration in mineral oil and alkyl benzene oil. In polyol esters, the number is generally accepted as 0.16 mg. Mineral and alkyl benzene oils with an acid number less than 0.05 mg or POE's with an acid number less than 0.16 mg are acceptable and will cause no change in the color of-the test kit's acid indicator. However, if the respective oils have an acid number greater than these limits, it will cause the acid indicator to change from purple to pink or clear indicating that the oil is contaminated.

Nu-Calgon Refrigeration Oil Acid Test Kit, Liquid Form, Clear/Colorless

• Simple phase separation make it easy to see color change in acid indicator
• Universal - use one kit for mineral oil, alkylbenzene, POE and PVE oils
• Precise phase III is a highly accurate service tool that can save expensive compressor repair and replacement costs
• Effective in the presence of dyes - many system will contain dyes, such as fluorescent colored dyes, for leak detection purposes, these dyes render most acid tests useless, not phase III, because of it phase separation, phase III make it easy to test such system
• Handy size - several phase III test kit can be carried conveniently in a toolbox