What was found
MAIN DOOR PRIMARY SEAL: WHEN YOU START THE APU THE GREY PRIMARY DOOR SEAL INFLATES. UNABLE TO CLOSE MAIN CABIN DOOR. PERFORMED A DETAIL INSPECTION. RAN APU AGAIN WHILE ACCESS PANELS WERE OFF TO SEE WAS VALVE FUNCTIONING PROPERLY. VALVE DID WORK PROPERLY. THE OUTER DOOR SEAL INFLATION VALVE WAS STUCK CLOSED AND WOULD NOT OPEN. REMOVED INFLATION VALVE AND CLEANED PLUNGERS. RE-INSTALLED INFLATION VALVE. STARTED APU APPLIED BLLED AIR AND PERFORMED OPS CHECKS. OPS CHECK OF VALVE IS SATISFACTORY. WORK DONE IAW AMM 52-10-04. NO FURTHER DEFECTS NOTED