Narrative:

After approximately 40 mins of cruise flight; an intermittent takeoff warning horn sounded. Cabin altitude was verified to be at 10200 ft and climbing slowly qrc memory steps were performed (masks; communication). My astute first officer had already selected 'standby' on the cabin pressure controller which caused the cabin altitude to begin to decrease. As a precaution we requested and received clearance to descend to FL240. After a radio conversation with dispatch and maintenance; we continued to ZZZ.

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Original NASA ASRS Text

Title: A B737 ACR FLT CREW EXPERIENCED A CABIN ALT WARNING HORN AT 34000 FT. THEY RAN THE QRC; DESCENDED TO 24000 FT; AND REGAINED CONTROL OF THE CABIN WITH THE STANDBY PRESSURE CONTROLLER.

Narrative: AFTER APPROX 40 MINS OF CRUISE FLT; AN INTERMITTENT TKOF WARNING HORN SOUNDED. CABIN ALT WAS VERIFIED TO BE AT 10200 FT AND CLBING SLOWLY QRC MEMORY STEPS WERE PERFORMED (MASKS; COM). MY ASTUTE FO HAD ALREADY SELECTED 'STANDBY' ON THE CABIN PRESSURE CONTROLLER WHICH CAUSED THE CABIN ALT TO BEGIN TO DECREASE. AS A PRECAUTION WE REQUESTED AND RECEIVED CLRNC TO DSND TO FL240. AFTER A RADIO CONVERSATION WITH DISPATCH AND MAINT; WE CONTINUED TO ZZZ.

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.