Troubleshooting Chart (Propeller Deicer System) - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
TABLE XIV-V. TROUBLESHOOTING CHART
(PROPELLER DEICER SYSTEM)
Trouble
Cause
Remedy
Ammeter shows zero
current. (All 4
phases of the 2
minute cycle.)
Tripped circuit
breaker switch.
Locate and correct short
before setting circuit
breaker.
No power from
airplane.
Circuit breaker
switch faulty.
Ammeter faulty. (If
some or all deicers
heat with ammeter at
zero, replace the
ammeter.)
Open ammeter to
timer.
4F12
If no voltage into
switch, locate and
correct open.
If no voltage at switch
output with voltage at
switch input, replace
the switch. If voltage is
satisfactory at switch
output, go to next step.
Test for voltage up to
and out of ammeter. If
low or zero output and
input satisfactory. re-
place ammeter. If no
voltage to ammeter, lo-
cate and fix open between
switch and ammeter.
Disconnect harness at
timer and check voltage
at Pin B (of harness)
to ground. If none, lo-
cate and correct open.
ACCESSORIES AND UTILITIES
Reissued: 9/23/80