TM1 and CS  vacuum system are connected. All turbo-pumps are started. The new TP1S works fine also. The pumping down looks good so far. During the TM1 and CS roughing down time, Joe .M noticed a Rn-220 level surge up in TH . Then,the Rn220  level slowly dropped back. Anders suspected this Rn-220 surging is related to the TM1 roughing down at CS. We decided we will stop the pumps , vent the CS , and roughing  again tomorrow. During the same time Joe will monitor  Rn-220 level in TH to see if the surging is repeatable. We want to learn more on this TH Rn-220 issue.