Sno valley completed cleaning of the Y end Chillers(7/19/110. we shifted from Chiller 2 and CWP2 to Chiller 1 and CWP1. we had a small temp excursion at Y mid station yesterday(7/19/11). This was from testing Robert S. was conducting at Y mid on the ventilation system. All systems were restored to their proper configuration. HFD on site to conduct hydrant flush prior to hydrant flow test.