15-7.2 CONTROLS AND INDICATORS FUNCTIONS TABLE
FUNCTION OF CONTROLS AND INDICATORS ON APU TESTER
Displays % engine speed from 0 to 120.
Color coded LED indicators
a. BYPASS (grn)
Lighted - indicates voltage is applied to start bypass
b. MAIN POWER (red)
Lighted - indicates main power is on.
c. MALF (red)
Lighted - indicates malfunction has occurred and unit
is shutdown. Bite indication on ESU is checked for
d. READY TO LOAD (grn)
Lighted - indicates APU is ready to accept load.
e. START COMMAND (grn)
Lighted - indicates start command is initiated,
f. MAX. AIR (red)
g. ECONO AIR (yel)
h. START FUEL (yel)
Lighted - indicates start fuel valve voltage on
approximately 5% RPM.
i. MAIN FUEL (yel)
Lighted - indicates main fuel valve voltage on,
approximately 14% RPM.
j. MAX. FUEL (yel)
Lighted - indicates max. fuel voltage on,
approximately 90% RPM + 5 sec. time out.
k. OIL PRESSURE (yel)
Lighted when MAIN POWER is lit. Does NOT indicate
1. BLEED VALVE OPEN (grn)
m REMOTE (red)
Lighted - indicates remote analog converter selected.
(Actual magnetic pickup and thermocouple probe.)
Controls 28 VDC power to Tester and ESU.
Refer to Paragraph 15-7.1 for location of items.
START/ RUN /STOP switch
Initiates start sequence of ESU and generates start
signal input to tester.
BLEED AIR OPEN/CLOSE
OVERSPEED TEST switch
MAX. AIR switch
ECONO AIR switch
Selects local or remote analog converter. LOCAL
(down position) selects analog converter in aircraft.
REMOTE (up position) selects analog converter in
tester. Always used in the REMOTE position.
TACH INPUT jacks
To monitor magnetic pickup input and input
BLEED VALVE VOLTS/
Output connector for harness connection to APU.
Connector J 1
Input connector for harness connection to ESU.
Input /Output connector for harness connection to
ESU and Airframe harness.
Displays exhaust gas temperature (EGT) in °F from 0
Lighted - indicates 28 VDC power is available to
tester. Illuminates panel meters.