Narrative:

At approximately 22000 ft, while climbing to 24000 ft, the cabin pressurization went to full up. The so had no control in either automatic or manual. I am the captain and was flying at the time. My first officer advised ATC that we had a pressurization problem and requested a lower altitude. The center cleared us to 11000 ft. I did not declare an emergency, but we executed an emergency descent. My training has always been to descend to 10000 ft if terrain permits. As we approached 11000 ft, the first officer advised me we were only cleared to 11000 ft. We were descending at a high rate of vertical speed and I stopped the descent at approximately 10400 ft and immediately climbed back to 11000 ft. We then requested further descent to 8000 ft which was approved. We returned to bos without incident.

Related reports:

Google
 

Original NASA ASRS Text

Title: AN ACR LGT LOST ITS PRESSURIZATION AND MADE AN EMER DSCNT PROC WITHOUT DECLARING AN EMER.

Narrative: AT APPROX 22000 FT, WHILE CLBING TO 24000 FT, THE CABIN PRESSURIZATION WENT TO FULL UP. THE SO HAD NO CTL IN EITHER AUTO OR MANUAL. I AM THE CAPT AND WAS FLYING AT THE TIME. MY FO ADVISED ATC THAT WE HAD A PRESSURIZATION PROB AND REQUESTED A LOWER ALT. THE CTR CLRED US TO 11000 FT. I DID NOT DECLARE AN EMER, BUT WE EXECUTED AN EMER DSCNT. MY TRAINING HAS ALWAYS BEEN TO DSND TO 10000 FT IF TERRAIN PERMITS. AS WE APCHED 11000 FT, THE FO ADVISED ME WE WERE ONLY CLRED TO 11000 FT. WE WERE DSNDING AT A HIGH RATE OF VERT SPD AND I STOPPED THE DSCNT AT APPROX 10400 FT AND IMMEDIATELY CLBED BACK TO 11000 FT. WE THEN REQUESTED FURTHER DSCNT TO 8000 FT WHICH WAS APPROVED. WE RETURNED TO BOS WITHOUT INCIDENT.

Data retrieved from NASA's ASRS site as of July 2007 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.