The T1 expansion tank warning level sensor had tripped and the level was approximately 1cm from the base of the tank.  No trip warning was observed when Tom Lyth checked the panels last week.  The T1 cooling package and target monolith were inspected and no water was observed.  Two puddles of water were found in the BL1A tunnel around the T1 package area: one directly below the 1AQ9 Cable Interlock Tray, and another approximately 1.5m to the west.  However, water was observed in the same area when the tunnel was accessed in January.  The T1 volume is currently vented, so there is no indication from the vacuum system as to whether or not water has leaked into the beamline.

The tank was refilled, and the level had not changed after 1 hour.  I will continue to monitor the level.