What was found
DECENT,ENG & WING A/I ON,RT WING A/IVLV DISAG, NR 1 MAN ALERT.PERF QRH , NR 1 THROTTLE IDLE,SECURED ENG AND WING A/I,DEP ICING,CLIMBED TO 280. 20 MIN LATER #1 MANI ALERT EXTINGUISHED RETURNED THROTTLE TO NORMAL POWER. CKD MAN FAIL DET UNIT, LEFT WING PRESS SW FAULT. ACP PNEU DECAY CHECK PER MM 36- 00-02 ALL THREE SYSTEM PASSED. DROPPED L/E SLATS, PUT AIR ON THE WINGS OPENED WING A/I FOUND NO PRESS DROP 28PSI. ALSO ACP INSPECTION ON WING L/E FOR ANY DUCT LEAKS AND CHECKED TELESCOPING TUBE ON BOTH WINGS. NO LEAKS. R/R RIGHT WING ANTI-ICE SHUTOFF VALVE PER M/M 30-11-02-2, OPS & LEAK CHECKS NORM. R/R NR 1 MAN FAILURE DETECTION PRESS SW M/M 36-23-03-4, OPS CHECKS NORM.