As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW RECEIVED A CABIN ALTITUDE WARNING CLIMBING THROUGH FL 270. THE QRH WAS FOLLOWED AND A RAPID DESCENT TO 13,000 FEET WAS ACCOMPLISHED. CABIN PRESSURE WAS RECOVERED VIA MANUAL DC. THE AIRCRAFT WAS RETURNED TO IAH WHERE IT LANDED WITHOUT FURTHER PROBLEM. A CABIN PRESSURE CONTROLLER WAS REMOVED AND REPLACED IAW MM 21-31-21, PAGE 401. OPERATIONAL CHECKS WERE GOOD IAW MM 21-31-00, PAGE 201.