Piper Cherokee Six - Page 688

PIPER
CHEROKEE
SIX
SERVICE
MANUAL
The
following
steps
should
be
of
help
when
performing
this
operation.
a.
Remove
access
panel
at
the
rear
of
the
cabin
to
gain
access
to
the
Schrader
service
valves.
CAUTION
Ascertain
that
all
system
pressure
is
released
before
attempting
the
evacuation.
(Refer
to
Paragraph
13-5.)
b.
Connect
the
manifold
gauge
set
to
the
airplane
service
valves.
(Refer
to
Figure
13-6.)
c.
The
high
and
low
manifold
hand
valves
should
be
in
the
closed
position.
(Refer
to
Figures
13-3
and
13-4.)
d.
Connect
the
center
manifold
hose
to
the
inlet
of
the
vacuum
pump.
NOTE
Make
sure
the
exhaust
port
on
the
vacuum
pump
is
open
to
avoid
damage
to
the
vacuum
pump.
e.
Start
the
vacuum
pump
and
open
the
low
side
manifold
hand
valve.
Observe
the
compound.
low
pressure
gauge
needle,
it should
show
a
slight
vacuum.
f.
Continue
to
operate
the
vacuum
pump
until
26
to
28
inches
of
vacuum
is attained
on
the
low
pressure
gauge,
then
extend
the
operation
for
another
25
minutes.
g.
If
the
system
cannot
maintain
26
to
28
inches
of
vacuum,
close
both
manifold
hand
valves
and
observe
the
compound
gauge.
h.
Should
the
compound
gauge
show
a loss
of
vacuum,
there
is
a leak
in
the
system
which
must
be
repaired
before
continuing
with
evacuation.
i.
If
no
leaks
are
evident,
reopen
both
manifold
hand
valves
and
continue
the
evacuation
for another
30
minutes.
j.
Close
both
manifold
hand
valves,
stop
vacuum
pump
and
disconnect
center
manifold
hose
from
the
vacuum
pump.
k.
Proceed
to
charge
the
system
in
accordance
with
paragraph
13-14.
NOTE
The
system
should
be
charged
as
soon
as
it
has
been
evacuated.
13-14.
CHARGING
THE
SYSTEM.
When
the
system
is
completely
evacuated
in
accordance
with
instructions
given
in
paragraph
13-13,
one
of
the
following
procedures
should
be
used
to
charge
the
system.
ACCESSORIES
AND
UTILITIES
Issued: 8/17/72
3G22