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    User name R. Subedi

    Log entry time 17:13:18 on December 20, 2009

    Entry number 308474

    keyword=Cause of Cryo-problem (copied from ELOG): the culprit of longer down time

    I have copied the exact language from the ELOG entry (1503884) that I see
    convincing for the cryo-problem we are facing since last night 10 PM so
    that people can see it remotely:


    Hall A target issue during the overnight hours was due to a return valve
    on the Refrigeration Recovery Heat Exchanger (RRHX). Due to some unknown
    event around 10 pm, the return valve on the RRHX went closed to prevent
    cold gas from going back to compressor suction. Once the problem was
    recognized and the recovery was almost complete, the ESR went down due to
    C2 oil pump issues.