At about 09:30 this morning I noticed the sound coming from the compressor 
building seemed louder than usual. After entering the building I noted that 
the compressor was unloaded to about 50% and the compressor suction was 
running at about 15 psig. Down at the SULZER panel the solenoid vacuum 
system was tripped off, the flow was still in series mode but no LHe level,
solenoid temps at over 40 K. Contacted Doug. Cannot figure out why the 
compressor was unloaded to 50 %. Solenoid had not tripped on bad vacuum 
because jumper was still on PIC901. Doug mentioned there was a power bump 
yesterday at about 15:00. May be when the vacuum system tripped but does 
not explain the compressor unloading.

Doug restarted vacuum system. I stopped flow to solenoid. Stabilized 
pressures. We checked the compressor to try to see what would cause the 
Unloaded state. Could not see any oil leaks. 

Back at Sulzer panel loaded compressor to 100 %. Stabilize pressures. STart
cooling flow to solenoid, // warm return. Adjusting turbine speeds and 
shield heat as required. Switched to // cold return flow after solenoid 
temps down to TIC 121 temp of about 20 K.