As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT WITH THE RT PACK DEFERRED PER MEL 21-51-01(C), THE LT PACK TEMP CAUTION MESSAGE ILLUMINATED. THE CREW FOLLOWED THE QRH AND RETURNED TO CLT. MAINTENANCE REMOVED & REPLACED THE DUAL POSITION VALVE IAW CRJ200 AMM 21-21-10-400-801. OPERATIONAL CHECKS WERE GOOD. THE MELS WERE CLEARED AND THE AIRCRAFT WAS RELEASED FOR SERVICE.