VALVE. WING ANTI-ICE PRESSURE REG S/O & TEMPERATURE CONTROL 17 CONTROLLER. WING ANTI-ICE SYSTEM TEMPERATURE 18 AUXILIARY POWER UNIT (APU) 19 AIR TURBINE STARTER & BLEED CONTROL VALVE 20 VALVE. DOOR SEAL PRESSURE REGULATOR 21 FILTER, SERVO AIR PRESSURE 22 VALVE. DUAL PORT SOLENOID SHUTOFF 23 VALVE, SOLENOID SH