Narrative:

While at flight level 370 our emergency pressurization came on. Thinking our cabin was depressurizing we put on our O2 masks and started a descent. We put 7700 in the transponder and once we were able to communicate with ATC they asked if we were doing an emergency descent. I confirmed and said we were having pressurization trouble. They cleared us to 10;000 ft and were very helpful. When we went through the checklist we found out that our acm ejector failed due to overheating and that emergency pressure takes over to allow the acm ejector to cool. We selected a warmer cabin setting and the system reset. No pressurization was lost. We continued our flight to destination.

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Original NASA ASRS Text

Title: CE500 Captain experiences Emergency pressurization coming on at FL370. Oxygen masks are donned; descent is initiated and 7700 is squawked before discovering that the ACM can be reset by selecting a warmer temperature.

Narrative: While at flight level 370 our Emergency pressurization came on. Thinking our cabin was depressurizing we put on our O2 masks and started a descent. We put 7700 in the transponder and once we were able to communicate with ATC they asked if we were doing an emergency descent. I confirmed and said we were having pressurization trouble. They cleared us to 10;000 FT and were very helpful. When we went through the checklist we found out that our ACM ejector failed due to overheating and that emergency pressure takes over to allow the ACM ejector to cool. We selected a warmer cabin setting and the system reset. No pressurization was lost. We continued our flight to destination.

Data retrieved from NASA's ASRS site as of July 2013 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.