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engine
operation
and clean
if oil has accumulated
in
delay
device.
Defective
components
may be replaced
the
filter
housing.
For a cleaning
agent use a com-
as
required.
mercial
hydrocarbon
type
solvent
such as
naphtha,
petroleum
ether,
or gasoline;
kerosene
type
distil-
Shuttle
Valves
lates
should
be avoided.
No field maintenance
is recommended
or authorized.
b.
Tavco
Control
Valve Installation.
Defective
valves
should
be returned
to
manufacturer
for
overhaul
or replaced.
Since
the
Tavco
shuttle
After
each
100
hours
of engine
operation,
remove
valve
is an integral
part
of the
complete
control
the
filter
cover
on each control
valve
assembly
to
valve
assembly,
the
entire
unit must
be submitted
dispose
of residual
oil in
the
filter.
for inspection.
Control
Valves
Component
Replacement
a.
Goodrich
Control
Valve.
No component
maintenance
other than
that
described
in
this
shop
manual
is recommended.
After
approximately
100 hours
of engine
operation,
the
valve
poppet
and internal
lining
of
the
control
valve
may
become
coated
with a film of dried
oil,
SURFACE
DEICER
SYSTEM
(PRESSURE)
causing
the
valve
poppet
to
stick.
To determine
if
the
valve
poppet
is sticking,
perform
the
checks
The surface
deicer
system
consists
of lightweight
outlined
in System
Checkout,
Control
Valves.
If
the
pneumatic
deicer
boots
cement-bonded
to the
wing
solenoid
ejects
the
hex actuator
pin (Step c,
2)
pro-
and empennage
leading
edges,
two
engine-driven
ceed
as follows:
dry air pumps
which provide
pressure
for
boot
inflation
and
evacuation,
and a distributor
valve
located
in
the
aft fuselage
section
which shuttles
.
air flow
to
and
from
the
deicer
boots.
1. Remove
the
solenoid
electrical
connector.
In operation,
the
engine-driven
pumps
supply
air
2. Remove
the
valve
poppet•
to a
manifold
assembly
in
the
pilots
compartment
and directs
it
to the
distributor
valve.
When
the
NOTE
distributor
valve
is actuated
to
inflate
the
boots,
a
time
delay
relay
is
energized
at
the
same
time.
It may be necessary
to
apply
slim
nose pliers
Mter
5
to
8 seconds,
the
relay
returns
the
distri-
to
the
pin projection
in order
to
pull
the
poppet
butor
valve
to
the
original
or "evacuate"
position.
from
the
valve.
In
the
"evacuate"
position,
the
air flow
is routed
through
an integrated
venturi
which
creates
a
3.
Thoroughly
clean the
control
valve bore
and
vacuum
in
the
deicer
supply
lines
to
hold down
the
poppet
with a commercial
hydrocarbon
type
solvent•
boots.
4.
Reassemble
the
valve
and reinstall
and safety
Either
an AUTOMATIC
or MANUAL
position
may be
the
solenoid.
selected
by
the
Deicer
Control
Switch located
on
the
instrument
panel.
The
AUTOMATIC
position
provides
b.
Tavco
Control
Valve Assembly.
one complete
cycle
of five
to
eight
seconds
before
resuming
a
hold-down
condition.
The
MANUAL
posi-
Sticking
of
the
valve
poppet
may be caused
by
a film
tion
will
inflate
the
boots
only
while
the
switch
is
of dried
oil on
the
poppet
and
the
interior
of
the
engaged;
when
the
switch
is released,
the
boots
will
valve.
The valve
may be cleaned
as follows:
return
to the
vacuum
hold-down
position.
A Deicer
Pressure
Gage
on
the
instrument
panel
indicates
1. Disconnect
the
valve
assembly
and remove
it
system
operation.
from
the
aircraft.
RESURFACING
DEICER
BOOTS
2.
Force
a commercial
hydrocarbon
type
solvent
into
the
inlet port of
the
valve
assembly
while oper-
Static
electric
charges,
if allowed
to
accumulate,
ating
the
solenoid
several
times.
would eventually
discharge
through the
boot
to the
WARNING
metal
skin beneath,
causing
static
interference
with
radio
equipment
and possibly
puncturing
the
rubber.
Also,
such static
charges
are
a
temporary
fire
Observe
the
normal
safety
precautions
hazard
after
each flight.
To dissipate
static
electric
required
for this type
of operation•
charges,
a
thin
coating
of conductive
cement
is
applied
over
the
neoprene
of
the
boot.
From
time
to time
it may be necessary
to
restore
the
conduc-
3. Reinstall
the
valve
assembly,
tivity
to
efficiently
dissipate
such charges.
The
principal
factors
involved
when
resurfacing
seems
Timer
advisable
are:
The
timer
consists
of a holding
relay
and a
time-
a.
If
the
surfacing
material
has abraded off.
3-52
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Table of Contents
Troubleshooting
