As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOST CABIN PRESSURE FL250, COULD NOT MAINTAIN CABIN IN EITHER AUTO OR MANUAL AT ALTITUDE. REPLACED THE WATER SEPARATOR SOCK AND ANTI-ICE PRESSURE REDUCING VALVE FILTER. OPERATIONAL CHECKS GOOD ON GROUND. AIRCRAFT RETURNED TO SERVICE. (M)