Piper Navajo Chieftain PA-31-350 Service Manual page 857

NAVAJO CHIEFTAIN SERVICE MANUAL
TABLE XIV-V. TROUBLESHOOTING CHART
(PROPELLER DEICER SYSTEM) (cont.)
Cause
Trouble Remedy
Ammeter shows nor-
mal current part of
cycle, zero current
rest of cycle.
Open in wiring between
timer and brush block
assembly.
Use heat test to find
deicers not heating and
test for voltage on that
contact of wire harness
plug. (At brush block
assembly.) If zero over
2 minutes, locate and
fix open in wiring from
timer to wire harness plug.
Open between brush
block assembly and
deicer lead straps.
No ground circuit,
one engine.
If there is voltage to
brush block wire harness
plug, try voltage at
junction of deicer lead
and slip ring lead. If no
voltage, find and correct
open in wiring within
brush block or no contact
of brush to slip ring.
If voltage is found at
deicer leads, locate and
fix open from deicer to
ground.
Ammeter shows nor-
mal current part of
cycle, low current
rest of cycle.
Inner and outer
deicers heating
same phase.
Locate and repair
incorrect connections.
Open in deicer or
slip ring leads.
4F13
Disconnect deicer straps
to check heater resistance
as in paragraph 14-52. If
satisfactory, locate and
fix open in slip ring leads.
ACCESSORIES AND UTILITIES
Reissued: 9/23/80