What was found
ON CLIMB OUT LEFT DUCT SHOWED 0 AT 13,000 CABIN ALTITUDE WOULD NOT CLIMB AND MAX CABIN DIF PRESSURE CONTINUED TO CLIMB, CABIN ALT WOULD NEVER CLIMB ABOVE 0 MSL. PERFORMED ENGINE HEALTH CHECK ON #1 FOUND 450 THERMOSTAT SENSE LINE LEAKING, HIGH STATE REGULATOR AND PRECOOLER CONTROL VALVE BAD. REPLACED SENSE LINE, HIGH STAGE REG PER AMM 36-11-07 AND PRECOOLER CONTROL VALVE PER AMM 36-12-02 TESTED PER 36-11-00-700-801 PRESURIZED AC WITH ENGINES PER 05-51-91-790-801 OPS CHECK GOOD.