Narrative:

Notified by flight attendant there was a vibration and noise in aft galley under the floor. Also had no running water anywhere in aircraft. Contacted maintenance and he had us pull circuit breaker for water compressor but did not help. Flight attendant said vibration and noise were getting worse. Could not identify source of problem. Decided to divert. Landing was normal. Callback conversation with reporter revealed the following information: it was discovered on post flight that the potable water servicing valve had been left in the open position. The open position of this valve prevented the tank from pressurizing and should have prevented the compressor from running. After servicing the aircraft was ferried and the water system functioned normally.

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Original NASA ASRS Text

Title: B757-200 CAPT REPORTS STRANGE NOISE AND VIBRATION EMANATING FROM BELOW THE AFT GALLEY. FLT CREW DIVERTS WHEN SOURCE CANNOT BE DETERMINED OR CONTROLLED.

Narrative: NOTIFIED BY FLT ATTENDANT THERE WAS A VIBRATION AND NOISE IN AFT GALLEY UNDER THE FLOOR. ALSO HAD NO RUNNING WATER ANYWHERE IN ACFT. CONTACTED MAINT AND HE HAD US PULL CIRCUIT BREAKER FOR WATER COMPRESSOR BUT DID NOT HELP. FLT ATTENDANT SAID VIBRATION AND NOISE WERE GETTING WORSE. COULD NOT IDENT SOURCE OF PROB. DECIDED TO DIVERT. LNDG WAS NORMAL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: IT WAS DISCOVERED ON POST FLIGHT THAT THE POTABLE WATER SERVICING VALVE HAD BEEN LEFT IN THE OPEN POSITION. THE OPEN POSITION OF THIS VALVE PREVENTED THE TANK FROM PRESSURIZING AND SHOULD HAVE PREVENTED THE COMPRESSOR FROM RUNNING. AFTER SERVICING THE ACFT WAS FERRIED AND THE WATER SYSTEM FUNCTIONED NORMALLY.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.