A CL600 AT FL340 NOTED CABIN ALT CLBING. HAD ONLY R PACK OPERATING AS L PACK HAD BEEN SHUT DOWN EARLIER. DISCOVERED R PACK DUCTING LEAKING.

Narrative

AFTER TKOF FROM ZZZ1 AT XA00 LCL; WHILE IN CLB AND TRANSITIONING FROM APU AIR TO ENG BLEED AIR WE HAD A L ACU OVER PRESSURE. AFTER CONSULTING AND COMPLETING THE CHKLIST FOR THIS PROC WE CONTINUED AS PLANNED. AFTER APPROX 10 MINS INTO FLT WE HAD A WOW (WT ON WHEELS) INPUT FAILURE LIGHT. THIS INDICATION WENT AWAY WITHIN APPROX 10 MINS. AS WE CONTINUED ON OUR PLANNED FLT AT FL340 ALL WAS NORMAL. APPROX 2 HRS INTO THE FLT AT FL340 WE HAD AN INDICATION THAT THE CABIN PRESSURE WAS RISING. AS THE PF I ELECTED TO DSND TO FL240. AT FL240 THE CABIN CONTINUED TO CLB. IT WAS OBVIOUS AT THIS POINT THE AUTO CABIN CTLR WAS NOT FUNCTIONING PROPERLY. WITH THIS INFO AND WITH 1 ACU SHUT DOWN ALREADY DUE TO THE OVERPRESSURE PLUS IN WOW INPUT FAILURE LIGHT SITUATION WE DECIDED TO CONTINUE THE DSCNT TO 10000 FT AND DIVERT TO ZZZ2. WHEN WE LEVELED AT 10000 FT THE CABIN WAS AT OR NEAR THE CABIN LIMIT OF ABOUT 8800 FT. DIFFERENTIAL CABIN PRESSURE WAS AT ABOUT 2 PSI. AT THIS POINT THE CABIN ALT STARTED DSNDING APPROX 200-300 FPM. AT 10000 FT AND APPROX 240 MI TO ZZZ2 WE WERE ABLE TO BURN OFF ENOUGH FUEL TO LAND AT MAX LNDG WT AND THE CABIN WAS ABLE TO DSND AT A COMFORTABLE RATE FOR THE PAX AND CREW. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE PROB WAS OPERATING WITH ONLY 1 AIR-CONDITIONING PACK AS THE L PACK WAS SHUT DOWN FOR OVERPRESSURE WARNING. MAINT DISCOVERED THE R PACK DUCTING WAS LEAKING EXCESSIVELY AND COULD NOT MEET THE PRESSURIZATION CTLR DEMANDS.