Learjet 60 - ALC LOW Caution Light; WSHLD ALC Switch

Pilot's Manual
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Learjet 60
WSHLD
ALC SWITCH
The windshield alcohol
anti-ice system is controlled by the WSHLD
ALC switch in the ANTI-ICE group
on the center switch panel . The
switch has two positions : WSHLD
ALC (On) and OFF . When the
switch is set to WSHLD ALC, circuits
are completed to open the shut-
off
and pressure regulator
valve and position the three-way control
valve
for alcohol flow to the
windshield . The alcohol reservoir, pres-
surized
to approximately 2 .4
psi above ambient through the
shutoff
and pressure regulator
valve, supplies alcohol to the
windshield out-
let through a filter
and the three-way control
valve
.
When the switch
is set to OFF,
the shutoff and pressure
regulator valve will close, the
three-way
valve will reposition to cut
off flow and system pressure
will bleed
off through the pressure relief
valve .
ALC
LOW CAUTION LIGHT
Illumination
of the amber ALC LOW light, located
on the glareshield
annunciator panel, indicates the alcohol
supply in the reservoir is
low . The reservoir float switch will illuminate the
light
through
a re-
lay
when in the full down position . When the
relay is energized, a
holding circuit is also energized to prevent
the light from flickering
due to the bobbing motion of
the float . The holding circuit is de-
energized when the
BATTERY switches are set to OFF and the alcohol
reservoir is filled . A
completely filled reservoir will supply the wind-
shield alcohol anti-ice
system with approximately 45 minutes of alco-
hol flow .
6-16
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PM-123
Original