ADJUSTMENT. - TM-55-4920-424-13-P0025

TM 55-4920-424-13&P

a. Disconnect harness connector from APU ignition exciter input. Insulate connector to prevent accidental contact.

Note

If desired, fuel lines may be disconnected from fuel solenoid valves rather than

from fuel manifold and start fuel nozzle. Connect suitable drain lines to fuel

solenoid valves, and place open ends of drain lines into a waste fuel container

(one-quart minimum capacity).

b. Disconnect APU fuel lines from fuel manifold and from start fuel nozzle.

c. Connect suitable drain lines to disconnected lines, and place open ends of drain lines into a waste fuel container

(one-quart minimum capacity).

d. Push in TURBINE CONTRO LS circuit breaker. (See figure 1-4.)

e. Move START-ON-OFF switch to ON.

f. Move RESET switch to RESET.

g. Move START-ON-OFF switch from ON to START, and motor APU until airfree fuel flows through drain lines; then,

move START-ON-OFF switch from START to OFF.

h. Pull TURBINE CONTROLS circuit breaker.

i. Disconnect drain lines, and connect APU fuel lines to fuel solenoid valves, or to fuel manifold and start fuel

nozzle.

j. Reconnect harness connector to APU ignition exciter.

3-9.

ADJUSTMENT.

3-10. Only the adjustment procedure for the APU fuel control is given in this section. For procedures for other APU

components refer to TM 55-2835-203-24.

a. Rated speed setting adjustment. (See figure 3-2.)

Note

Clockwise rotation increases speed; counterclockwise rotation decreases speed.

A one-quarter turn (90 degrees) in either direction will change the speed

accordingly by approximately 65 rpm (approximately 1.5 percent speed).

(1) Insert a 3/32-inch hex-type wrench in setscrew. Loosen locknut and turn setscrew in required direction.

3-4