28i jun condensing combi keep flashing slow flashes ?

went to fix the 28 i jun cond/combi blue light flashes slow ones, replaced heat control , two over heat stat , and bcp did work fine for a day but it came back to start flashing again . it has been serviced , cond trap been cleaned , adjust gas rate to the right 9.8% ,but is still the same after 2 hours or more it flashes again need reseting . any advice