Maintenance Airframe; Maintenance Powerplant
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Air Traffic Control Provided Assistance; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Gate; General Flight Cancelled / Delayed; General Maintenance Action
Procedure; Incorrect / Not Installed / Unavailable Part; Aircraft; Manuals
Aircraft was leaving from ZZZ to ZZZ1 and aircraft did not pressurize. Crew returned to field. Aircraft was in maintenance overnight with a double windshield change which requires [aircraft] to be pressurized to verify no leaks. Manual switch on the avionics ventilation overboard extract valve was missing labels for on\off position. Add perform a bite check of the avionics extract fan ventilation system; to verify proper operation of closing and opening of the valve.
[Report narrative contained no additional information.]
Technician reported an improper windshield change lead to aircraft's inability to pressurize.