As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOW DUCT PRESSURE NOTED WITH BOTH PACKS RUNNING, PACK OUTPUT PRESSURE LOW AND COCKPIT TEMP HIGH (<P>MEL 36-11-04 RAISED & DDG COMPLIED WITH. REACTIVATED APU AIR SUPPLY SHUTOFF VALVE TO OPEN. PFM APU STARTING & OPS FOR TROUBLESHOOTING AND APU SURGE CONTROL VALVE STUCK IN OPEN POS. REPLACED THE SURGE CONTROL VALVE. PEFORMED APU START, OPS CHECKED PACK DUCT PRESSURE, ALL NORMAL. PFM APU CONTROL UNIT BITE TESTED OK IAW AMM 49-61-05, 49-11-00 &49-61-05. 3.