What was found
ACM BLD LEAK AMBER CAS: AT FLIGHT LEVEL 220, THE ACM BLEED LEAK QUICKLY FOLLOWED BY THE EMER PRESS CAS MESSAGES ILLUMINATED. WE COMPLETED THE ACM BLEED LEAK AND EMER PRESS QRH CHECKLISTS. THE CABIN TEMP WENT TO 124 DEGREES AND THE COCKPIT TEMP WENT TO 93 DEGREES. THE APU WOULD NOT START IN THE AIR OR ON THE GROUND. WE COULD NOT CONTROL THE TEMP SUPPLY BY ANY MEANS. OUR PASSENGERS CONTINUALLY UPDATED US ON THE HOT CABIN TEMP AND SMELL. R & R APU CONTROL PCB WITH A NEW UNIT. PERFORMED OPS CHECKS OF SYSTEM NO DEFECTS NOTED. WORK DONE IAW CE-680AS AMM 24-60-35.