What was found
DURING CRUISE AT 25000 WITH 1 PACK OFF DUE TO MEL, WE KEPT ON GETTING THE FLOW LIGHT & CABIN PRESS WAS SLOWLY CLIMBING. RAN EQRH 21.8 INCLUDING INCREASE THROTTLES PSI ON LT PACK, OPERATING PACK WAS AROUND 30PSI. WE DESCENDED TO FL220 & WERE STILL SHOWING THE FLOW LIGHT. MADE THE DECISION TO DIVERT & AFTER ABOUT 5-10 MINS AT FL220 THE FLOW LIGHT EXTINGUISHED & CABIN PRESS STARTED TO COME DOWN TO THE CORRECT CABIN ALTITUDE. R & R PRESS REGULATOR VLV LT IAW MM 21-31-01 & LT FLOW CONTROL VLV IAW MM 21-31-02. OPERATIONS & LEAK CHECKED NORMAL. COMPLIED WITH SINGLE PACK OPERATIONAL TEST IAW TASK CARD F0612102. OPERATIONS CHECKED NORMAL. NO OTHER DEFECTS NOTED.