AN A320 FLT CREW EXPERIENCED FUEL TRANSFER SYSTEM MALFUNCTION; DECLARED AN EMERGENCY; AND RETURNED TO THEIR DEP ARPT.

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AFTER TKOF; DURING INITIAL CLB; ECAM MESSAGE 'OUTER TANKS XFERRED' WAS NOTED AND CONFIRMED ON THE FUEL PAGE. WING TANKS HAD ABOUT 12000 LBS EACH AND CTR TANK HAD ABOUT 11000 LBS. OUTER TANK XFER VALVES WERE OPEN IN BOTH WINGS AND OUTER TANK FUEL WAS DECREASING. CTR TANK PUMPS WERE OBSERVED TO BE OPERATING NORMALLY DURING SELF-TEST CYCLE ON TAXI OUT. HOWEVER; CTR TANK PUMPS WERE NOT OPERATING DURING CLB AFTER SUITABLE WING FUEL WAS USED. CTR TANK PUMPS COULD BE MANUALLY TURNED ON WITH MODE SELECTOR PB IN MAN POS BUT CREATED THE RISK OF OVERFILLING THE WING TANKS. OUTER TANKS DECREASED TO ZERO. MESSAGES WERE SENT TO MAINT AND ACTIONS WERE TAKEN TO CORRECT THE PROB BUT THE SUGGESTED CYCLING OF FUEL PUMP PBS HAD NO EFFECT. FLT WAS INSTRUCTED TO RETURN TO ZZZ AT ABOUT 70 MI E OF ZZZ1. ACFT CONFIGN WAS CHANGED TO TRY TO BURN DOWN TO LNDG WT AS MUCH AS POSSIBLE. FLT LANDED AT 156000 LBS; MAX LNDG WT 142200 LBS FOR THIS ACFT. CABIN CREW WAS ADVISED OF RETURN TO ZZZ WITH BRIEFING OF WHAT TO EXPECT AND CONTINGENCIES IF TIRES BLEW. EMER DECLARED WITH ATC AND EMER EQUIP WAS REQUESTED. QRH OVERWT LAND PROC COMPLIED WITH. TOUCHDOWN AT 156000 LBS AND ABOUT 50 FPM DSCNT RATE NOTED BY PLT MONITORING. NORMAL ROLLOUT AND TAXI-IN. FUEL WRITE-UP AND OVERWT LNDG WRITE-UP ENTERED. ACFT CHANGE FOR CONTINUATION AS WELL AS FO CHANGE DUE TO DUTY TIME LIMITS.