Pete, if you want to know what is going on with your equipment, testing acid, moisture and wear particles will only give you part of the picture. The refrigerant is an integral part of the system and interacts with the lubricant both physically and chemically. Moisture and acidity are two useful tools, but need to be examined with the rest of the physical and chemical properties of the lubricant and refrigerant, especially if you want to identify the root cause of potential problems with the system.
I know it may be unpopular to say this on the site, but wear particle analysis of refrigeration lubricants is not widely used by the labs who specialize in these systems, including the OEMs who build and life test the compressors. By the time you see larger particles, the system is already toast. The smaller particles are easily picked up by the ICP metals analysis. Particle analysis may be useful to give a proper post mortem, but you will get the same information when you tear apart the failed compressor.
I am a firm believer in the analysis of critical HVAC/R equipment. The HVAC/R contractors who service equipment on a fixed cost annual basis do a lot of oil testing to monitor the condition of the equipment. Those that service equipment on a get paid to fix it when it breaks basis do not do oil or refrigerant testing, unless it is specified by the equipment owner. The economics change when you get paid to prevent equipment problems, rather than paid to fix equipment problems. As an equipment owner with a lot of money riding on outages, you should want to be in the first category.
