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3.2.11
Trouble Shooting, Heater System
-
For trouble
shooting,
heater
system
see
Chart 3-1.
3.2.12
Heater
F.e
moval
-
(a)
Remove access cover in lower outboard
side of forwar
d
bulkhead in nose baggage compart-
ment.
(b)
(c)
(ct)
Disconnect s park
plug
lead from heater.
Remove
floor
panel over heater.
Remove the
two floor
supports
above
the
heater.
(e)
Disconnect fuel inlet line at valve in nose
wheel well and
pull
through
grommet.
(f)
Unfasten rubber
drain
line
from
right
side
of
nose wheel well
and
remove
cover
plate through
which it protrudes.
(g)
Disconnect flexi!Jle combustion air tube
from
heater.
(h)
Disconnect metal drain line from bottom
of
heater.
(i)
Unfasten
clamps
and
remove
heater.
3.2.13
Minor Repairs and Parts Replacement,
Heater
-
Minor repairs
of
the heater will consist of
replac
e
ment
of broken
o~ worn high-tension
lead,
spark plug,
fuel line fittings,
or
fuel nozzle. The
fuel
nozzle
may be cleaned
with an approved
solvent.
If
evidence of corrosion
is found, the
entire
nozzle
should be replaced.
When assembling the heater, all
male
threads
s
hould
be coated with anti-seize com
-
pound, Specification
AN-C-53.
CAUTION
In
cleaning
the
fuel
nozzle,
do
not use
a
me-
tallic tool or
abrasive
,
since the
flow
char-
a:teristics of the nozzle m ay be
altered. A
sharpened toothpick
is
r ecommended
for
cleaning the
orifice and
the
grooves
in
th
e
nozzle
core.
3.2.14
Minor Repairs and Parts Re place
ment,
Heater
Ignition
-
Repair of loose
or
br ol-::2n
external
connect-
ions only should
be
attempted in the
field.
The
vib-
rator contact switch is safety-wired
at
the
in
position,
placing
the normal vi'>rator
contacts in
service,
on
installation
of the unit.
If
the
wire
is
broken
and
the
switch pulled
out,
the reserve contacts
are
in service.
On
installation of
a new
vibrator,
the
switch
should
again
be
safety wired with
the
normal contacts in
service.
If
replacement of the
vibrator
does
not re-
store normal
function of
the
unit, the
entir
e
unit should
be replaced.
CAUTION
In cleaning
the
ignition unit or wiring, do not
use carbon
tetrachloride
,
trichloroethylene,
or other
chl orinated
solvents
.
3.2. 15
(a)
Heater
Ins
tallation
-
Align exhaust
outlet
and
insert
heater
in
4
mounting position.
(b)
Fasten heater mounting
clamps,
making
sure
that clamps
seat
properly
over
beads in
order
to
obtain
a
good seal.
Safety
c lamps.
(c)
Attach metal drain line.
(d)
Attach fl
exi:Jle
air tube.
(e)
Insert
rubber drain line
through
cover plate
and
fasten cover and line as removed.
(f)
Insert fuel inlet line
through grommet
and
attach to valve in nose wheel well.
(g)
Install
fl
oor supports
and floor panel.
(h)
Connect lead to
s
park
plug.
(i)
Install
spark
plug access cover.
3.3
ENGINE PREHEAT SYSTEM
The engine preheat
system
is not installed in
the airplane as it comes
from
the factory
but
may
be
installed as
optional
equipment. The engine preheat
system
consists
of two
insulated flexible
hoses
, run-
ning from the
plenum
chamber in the lower right
side
of
the
nose
section,
to each nacelle.
These
flexible
hoses
are
fitted
with quick
disconnect
connections
and
plug
into
the
inboard side of
eac
h
nacelle.
They
are
s
towed
in the
belly,
beside
the heater plenum,
when not in use.
3.3.1
Operational Procedure
-
NOTE
External
power
shoul
d be used
to operate
t
he engine
preheater,
since
the
:Jatteries
have insufficient
capacity
to
operate
th
e
heater
over
a prolonged
period and
s
till
start the
engines
.
(a)
Open
access doo
r in belly, beneath nose
ba gga
ge
compartment, to
gain
access to the flexiiJle
hose.
('J)
Remove
free end
of
flexible hose and plug
into
a
ccess
door
in
the inboard
lower
side
of each
nacelle.
(c)
Operate
cabin heater.
NOTE
As there is
no
separate
thermostat
to
con-
trol
the
heat in
the
engine compartments,
for
ext
reme
cold weather starting
turn the
cabin thermostat
to the highest setting
to
allow the
maximum heat to enter
the engine
compartment.
Cabin
door
and windows
must be closed.
3.4
ASSIST
STEP
MECHANISM
3.4.1
Desc
ription -
An
assist
step for
boarding
the airplane
auto-
matically
lowers when landing gear struts
are
com-
pressed
on
landing
and
retracts
when struts extend
on takeoff.
A micro
switch,
in the same housing
as
the landing
gear safety switch
and
operated
by the
same plunger, controls the
system,
while up
and
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