Predictive Maintenance Includes Analysis and Testing Predictive maintenance services include: oil and lithium bromide analysis, vibration analysis, eddy current testing, ultrasonic testing, infrared testing, and motor current analysis.The timing of these services varies. Guiding factors should be the age of the equipment: how critical the chiller is to the operation and productivity of the facility, whether the units have a history of unexpected failure, and if they fail, what safety problem could arise?Oil and lithium bromide analysis should be done annually. The oil analysis would show indicators of wear metals, contaminants, viscosities and inhibitor levels. When performed annually, it's easy to trend by using charts showing the condition of the oil. We had performed oil analysis testing for a customer for many years. In one year the tin and iron increase considerably.The decision was made to open and inspect the compressor. The thrust bearing had worn to the point where it would not have been long before there would have been damage to the impellor. We replaced the bearings and the chiller has been running fine since.Lithium bromide analysis shows what the chemical balance is of the solution in the absorber. The analysis would tell you what the inhibitor levels are, whether ammonia is present, solution percentage, octyl alcohol content, alkalinity, copper, and foreign contaminants.Without knowing the chemical balance, you run the risk of prematurely ending the life of the chiller.The vibration analysis also should be done annually. This test indicates an imbalance, misalignment, bearing defects, open rotor bar conditions, gear wear, harmonics, and excessive shaft run-out.Eddy current testing is a non-destructive test of the heat exchangers within the chiller. It can detect inside diameter and outside diameter defects. The test also determines the severity of the defect and whether immediate action should be taken. We recommend this test be done every three to five years.Ultrasonic, infrared, and motor current analysis are important predictive maintenance tools that should be a part of the customers' maintenance budget. All three help to confirm whether the chillers are operating reliably and efficiently as possible.