During the power outage recovery,(06/06/2016) took the opportunity to replace the PSL in-line coolant filters. 

   The first set of filters are located in the Chiller Room on the discharge side of the chiller. There was some debris in the bottom of the Crystal Chiller filter. There was significantly less debris in the bottom of the Diode Chiller filter. There was little difference in the discoloration between the two filters in the Chiller room. After 31K hours of operations these filters are in very good condition. 

   The second set of filters are located in the PSL enclosure on the intake side of the cooling system manifold block. There was very small amount of debris in the bottom of the Crystal chiller filter. There was no noticeable debris in the Diode chiller filter. There was no noticeable difference in discoloration between these two filters. As expected, these filters were not as discolored as the filters in the Chiller Room. 

   In general, the PSL filtration appears to be working very well. In the future, these filter will be replaced at the same time the primary and backup chillers are swapped (planned for once a year). 

   I am working on getting a local lab to analyze the debris from the Cristal chiller. When we know what all this material is, we can make a better informed decision as to the internals of the PSL cooling system.