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put in use by adding
a 20 gage jumper
wire
between
saturated
with
solvent,
making
sure
that
no solvent
terminals
"A" and
"B"
on
the
heater
ignition
unit
gets
into
the
electrical
parts.
Inspect
the
plunger
(see
wiring
diagram).
On
Aircraft
prior
to
TD-534,
cap,
seal
and
spring.
Replace
these
parts
if worn
and
beginning
with
TD-'708
and after,
the
change-
or
damaged.
Blow out
the
valve
body with
com-
over
to the
alternate
set of
points
is
accomplished
pressed
air
before
reassembling.
by a point
selector
switch
located
below
the
left
instrument
panel.
When
the
alternate
set of
points
has been used
for
1000 hours
of
heater
operation,
CLEANING THE
HEATER
replace
the
vibrator.
Failure
to
switch
to the
alternate
set
of points
at
1000 hours
may
make
the
a. Cleaning
the
Combustion Chamber and
Radiator
alternate
set of
points
inoperative.
Assembly.
Either of the
two
following
methods
may
be used
to
clean the combustion chamber:
4
5
1. Soak
the
combustion
chamber
and radiator
1
2
3
assembly
in an
Oakite
M-3
stripper
solution for
10
hours.
The
solution
is made by mixing
one pound of
Oakite (Oakite Products,
Inc.,
22 Thames
Street,
New
York 6,
New
York)
with
each
gallon
of
water
--
_¯
used.
The solution should
be maintained
at a
tem-
perature
between
190
to 210
degrees
Fahrenheit
during
the
soaking period.
Flush
the
heater
thor-
oughly
with water
after
it is removed
from
the
1. Retaining
Ring
3.
Radio Noise
Shield
Oakite solution.
2. Vibrator
4.
Support Collar
5. O-ring Packing
2. Use a stainless
steel
brush
or sandblast
to
remove
any
accumulation
of carbon or other foreign
Figure
3-13.
Ignition
Unit Assembly
material
from
the
inside
of the combustion
chamber.
Clean
thoroughly
with
compressed
air.
REPLACING
IGNITION
VIBRATOR
b.
Cleaning
the
Spray
Nozzle.
a.
Remove
the
safety
wire
and
the
vibrator
retain-
1.
Disassemble
the
spray
nozzle
by unscrewing
ing ring
(1).
the
fuel strainer
and
two
piece
core
from
the
nozzle
body.
b.
Remove
the
vibrator
(2)
and radio
noise
shield
(3).
2. Clean the
parts
in Stoddard
solvent.
NOTE
3. If soaking fails
to thoroughly
clean the
parts,
scrub them
with
a soft, non-metallic
brush.
Be careful
that "O" ring
packing
(5)
does not
drop
out of place
while replacing
the
vibrator.
4.
The
grooves
in
the
core
and
orfice
in
the
body,
may be
cleaned
with
a soft
pointed
piece
of
wood.
c.
Install
new vibrator
(2)
with radio
noise shield
(3).
NOTE
d.
Install
the
vibrator
retaining
ring
(1).
Do
not use
a
metal
tool
for cleaning the
parts
¯
as
it will
alter
the
flow
characteristics
of
the
e.
Safety
wire
the
retaining
ring
to
one of
the
nozzle.
screws
in
the
vibrator
support collar
(4).
5.
When
reassembling
the
spray
nozzle,
tighten
the
core with
a screwdriver
and
the
strainer
with
HEATER
SOLENOID VALVE
the
fingers.
Check the
valve
operation
by connecting
a 24-volt
DC
power
source
with
an ammeter
with
a 0-1
ampere
COMBUSTION
CHAMBER
AND
RADIATOR
range
in
the
line.
Turn
the
power
on
and
off several
INSPECTION
times.
The valve
should draw
0.26
amperes
current
and click
when
the
valve
opens.
a.
Slight
scaling and
discoloration
of
the
combus-
tion
chamber and
radiator
assembly
is
a
normal
To check for
valve
leakage,
apply 35
psi
air pressure
condition
on
heaters
that
have been in use.
The
to the
inlet
end of
the
valve
and submerge
the
outlet
scale
will
be
mottled
and
a
blue powder
can
be
end in water
(check
direction
of flow
arrow
on
valve).
rubbed
off of
the
scaled areas.
This does not
If
the
valve
leaks
more
than
20
bubbles
per minute,
constitute
ground
for
rejecting
the
heater
since
clean
the
valve and
recheck.
considerable
life can still
be
expected
if
there
are
no
soft spots
in
the
metal
where
it
has
been
sub-
To clean
the
valve,
wipe all parts
with
a soft
cloth
jected
to
severe overheating.
3-25
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Troubleshooting
