Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 408 / 881

INSTALLATION.
1. Position the new lamp in the receptacle of the socket, then secure the socket in the retainer with the screws.
2. Activate the switch in the cockpit to check the lamp operation.
3. Replace the nacelle access panel with the attachment hardware.
CARBURETOR ICE DETECTOR. (PA-44-180 Only) (Excluding S/N 44-95001 and up)
DESCRIPTION.
The ARP Carburetor Ice Detector unit (one for each carburetor) used on the PA44-180 utilizes an optical probe
installed in the carburetor throat just upstream of the throttle valve. As ice forms and blocks the passage of light
within the probe, the warning is triggered. When the ice has melted and enough light is sensed, the warning light
will be extinguished. The probe has an expected service life of 50,000 hours. A built-in test circuit is activated
such that each time the switch is turned on the light will come on momentarily.
TROUBLESHOOTING.
— CAUTION —
DO NOT ATTEMPT TO TEST THE PROBE OR INSTRUMENT BY
A P P LYING A VO LTAGE TO EACH! A VO LTAGE OF OVER 2 - VO LT S
WILL BURN OUT THE PROBE LAMP AND SENSOR AND THE
INSTRUMENT RED LIGHT SWITCHING TRANSISTOR.
1. The probe may be tested as follows:
(1). Connect red (+) ohmmeter test probe to black wire of ice detector probe.
(2). In a subdued light (not in sunlight) touch the black ohmmeter test probe to the red wire of the ice
detector probe while observing the ohmmeter. The reading should be approximately 600 ohms in
ordinary light. Cover the ice detector probe sensor to eliminate most of the light. The ohmmeter
should indicate approximately 10,000 + ohms indicating that the sensor is functioning properly.
(3). Remove the black ohmmeter test probe from the red wire and touch it to the white wire. The
ohmmeter should read approximately 5 ohms indicating that the probe lamp is functioning properly.
(4). If both steps (2) and (3) above are completed satisfactorily the probe should operate.
(5). Test probe housing for short to ground. Housing is insulated.
2. The instrument is tested as follows:
A. Disconnect the ice detector probe at the probe connectors.
B. Apply (+) 12 - volts DC to instrument power wire (red wire with fuse holder).
C. Connect the black ground wire to (-) 12 - volts DC.
D. Turn the instrument on. The red light should come on. If the red light does not come on, the
instrument is inoperative and must be returned to:
ARP Industries Inc.
36 Bay Drive E.
Huntington, New York 11743
— Note —
ARP Industries, Inc. is the only FAA approved repair station for this instrument.
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
3 0 - 8 2 - 0 2
Page 30-48
Revised: May 15, 1989
2F4
PIPER AIRCRAFT