ACR LGT UNABLE TO PRESSURIZE AFTER TKOF HAD TO RETURN AND LAND.

Narrative

THE FLT ATTENDANT HAD TROUBLE LOCKING THE R1 ENTRY/SVC DOOR. I WENT TO ASSIST HER. I PARTIALLY REOPENED THE DOOR; THEN CLOSED IT AND STOWED THE HANDLE. AT THIS TIME THE R1 DOOR LIGHT ON THE EICAS PANEL WAS OUT AND PUSHBACK WAS STARTED. AT TIME OF PUSHBACK ALL DOOR LIGHTS WERE EXTINGUISHED. WHILE PUSHING BACK THE FLT ATTENDANT CAME FORWARD AND ASKED FOR SOMEONE TO HELP HER IN ARMING THE R1 SLIDE. WHILE PUSHING BACK THE FO WENT BACK TO LEND ASSISTANCE. HE RETURNED TO THE COCKPIT TO SAY IT LOOKED ARMED BUT HE COULDN'T BE SURE AS THE LIGHT WAS NOT ON AND SUGGESTED I TAKE A LOOK. WHEN WE STOPPED THE PUSHBACK I ASKED THE TUG DRIVER TO STAY HOOKED UP AS WE MIGHT HAVE A DOOR PROB. I WENT BACK TO CHK THE ARMING LEVER. WHILE THE LIGHT WAS NOT ON; THE LEVER APPEARED TO BE IN THE PROPER POS. AT THIS TIME I DECIDED TO PROCEED WITH THE DEP. AFTER DEP THE ACFT WOULD NOT PRESSURIZE. UPON RETURNING TO THE RAMP THE R1 DOOR WAS FOUND TO BE CRACKED OPEN. AT THIS TIME THE R1 DOOR LIGHT WAS STILL OUT. HOWEVER; THE HANDLE HAD CREEPED OUT OF THE STOWED POS. SUPPLEMENTAL INFO FROM ACN 95418: ON INSPECTION; DOOR APPEARED CLOSED (HANDLE WAS FULLY DOWN); BUT SLIDE ARMING LEVER WAS SOMEWHAT SPONGY FEELING TOWARD END OF TRAVEL; BUT WENT TO CORRECT POS 3. WE HAD NO ARMED LIGHT ON THE DOOR; SO I WAS UNCERTAIN AS TO STATUS OF DOOR (NO RED LINE WAS VISIBLE THROUGH VIEWING PORTS WHICH WOULD INDICATE L SIDE WAS UNARMED. THE CAPT RECYCLED THE DOOR AND RETURNED TO COCKPIT--SAID DOOR WAS CLOSED AND IT APPEARED SLIDE WAS ARMED EVEN THOUGH WE HAD NO ARMED LIGHT ON THE DOOR.