As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORIGINAL PROBLEM WAS ERRATIC PRESSURIZATION. TROUBLESHOT SYSTEM DOWN TO A BAD PNEUMATIC RELAY. REMOVED AND REPLACED RELAY AND ACFT FAILED FUNCTIONAL CHECK FLIGHT. ACFT HAD NO PRESSURIZATION. REMOVED AND REPLACED WITH SECOND NEW RELAY. SYSTEM OPS AND CHECKS GOOD ON GROUND AND PASSED FUNCTIONAL CHECK FLIGHT.