As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN TEMPERATURE VERY DIFFICULT TO CONTROL IN ALL ZONES. ACCOMPLISHED FIM 21 61 TASKS 861 862 863 & 864. FOUND ALL FILTERS WITH HEAVY SEDIMENT. CLEANED FILTERS AND ACCOMPLISHED MM 21 61 00. CHECKS OK. ACCOMPLISHED FIM 21 61 TASK 862E(3C). NO DEFECTS FOUND, NO FAULTS NOTED. REPLACED TRIM AIR PRESSURE REGULATOR AND SHUTOFF VALVE. ACCOMPLISHED TRIM AIR PRSOV ADJUSTMENT TEST AS PRECAUTIONARY ACTION.