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 SHUTOFF. TOTAL TEMP PROBE 24 SWITCH. BLEED AIR OVERPRESSURE (65 PSI) 25 TRANSMITTER. BLEED AIR/COWL PRESSURE 26 FILTER. CA