As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WOULD NOT PRESSURIZE AFTER TAKE-OFF. CREW RETURNED TO THE FIELD AND DECLARED AN EMERGENCY. THE AIRCRAFT JUST HAD THE SERVICE DOOR INDICATION AND THE GROUND VALVE MEL'D IN DCA JUST PRIOR TO THIS FLIGHT. DCA MX RECHECKED THE GROUND VALVE FOR PROPER POSITION FOR THE MEL AND NOTHING ABNORMAL WAS FOUND. PRESSURIZED AIRCRAFT WITH THE CREW AND COULD NOT DUPLICATE THE PROBLEM, OPS CHECK GOOD.