B737 DOES NOT PRESSURIZE AFTER TKOF FROM ANC; AK.

Narrative

SHORTLY AFTER TKOF; AUTOPRESSURIZATION FAILED. RAN CHKLIST AND DETERMINED THAT CABIN COULD NOT BE PRESSURIZED IN AUTO; STANDBY; OR MANUAL. NOTIFIED FLT ATTENDANTS OF POSSIBLE RETURN. FLT ATTENDANT CALLED BACK AND TOLD US THAT THERE WAS A NOTICEABLE AIR NOISE AT THE BOTTOM OF DOOR L2. WITH INDICATIONS OF A DOOR SEAL PROB WE RETURNED TO THE ARPT. SHORTLY AFTER WE GOT BACK ON THE GND; I GOT THIS NAGGING FEELING THAT WE HAD TAKEN OFF UNPRESSURIZED. MAINT INVESTIGATION SHOWED THE DOOR TO BE OK. AFTER INITIAL PUSHBACK WE HAD THE ACFT DEICED. DEICING CALLS FOR THE ENG BLEEDS TO BE TURNED OFF AND REMAIN OFF FOR 1 MIN AFTER DEICING TO HELP PREVENT FLUID FROM ENTERING THE DUCTS. I WANT TO BELIEVE THAT WE TURNED THE BLEEDS BACK ON BECAUSE WE WENT SO FAR AS TO START THE CLOCK FOR A 1 MIN TIMING; AND BOTH NOTED WHEN 1 MIN WAS UP. MAINT CHANGED THE PRESSURE CTLR AS A PRECAUTION; AND WE WERE EVENTUALLY ON OUR WAY. THIS EVENT AGAIN SHOWS THE NEED TO BE EXTRA VIGILANT WHENEVER DEVIATING FROM THE ROUTINE.