As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MULTIPLE BAROMETRIC CONTROL VALVES INSTALLED AND FAILED "OUT OF BOX". VALVES WERE INSTALLED AS MODIFIED PART NUMBER OF CONTROL VALVES IS K39117/3, SERIAL NUMBERS THAT FAILED WERE S/N 1044/1 AND S/N 2301/2. BOTH UNITS WERE INSTALLED AS "MODIFIED"