What was found
DURING CLIMB 240 TO 280, RECEIVED A "FLOW" ON LIGHT, QRH PROCEDURE WAS COMPLETED, STAYED AT 240, FLOW LIGHT CONTINUED AND THE CABIN ALTITUDE CLIMBING, 100NM FROM DPARTURE, TO AVOID A CABIN PRESSURE PROBLEM, THE CABIN ALTITUDE 7600' AND IN CLIMB, AT 300 FPM, DECIDED TO RETURN AND LAND AT DEPARTURE.