Piper Cherokee Six - Page 687

COMPOUND GAGE
PULL
26
TO 28
INCHES
VACUUM
COMPOUND
GAUGE
READING
IN
INCHES
OF MERCURY
VACUUM
PIPER
CHEROKEE
SIX
SERVICE
MANUAL
PRESSURE
GAGE
CHARGING
STAND
VACUUM
PUMP
SCHRADER
VALVE
SCHRADER VALVE
NOTE:
OPEN
BOTH SERVICE
VALVES
(COUNTERCLOCKWISE)
ONE
TURN
EVAPORATOR
ASS'Y
Figure
13-6.
Evacuation
Hookup
13-13.
EVACUATING
THE
SYSTEM.
If the
system
has
been operated
in a discharged
condition
or
anytime
the
system
has
been
open
to
atmospheric
pressure.
the
receiver-dehydrator
must
be
replaced
and
the
system
evacuated
to
remove
any
trapped
aft
and moisture
which
has entered
it. A
vacuum
pump
capable
of
pulling
29 inches
of
mercury
or better
should
be
used.
As we
lower
the pressure
in the
air conditioning
system,
we lower
the boiling
temperature
of
the water
(moisture)
that
may
be present.
Then
we are
able
to
pull
this
water,
in the
form
of
vapor,
out
of the
system.
The
following
table
demonstrates
the effectiveness
of
moisture
removal
under
a
given
vacuum.
System
Vacuum
27.99
28.89
29.40
29.71
29.82
29.88
Temperature F.
100
80
60
40
20
0
NOTE
For each 1,000
feet of elevation above
sea level, the
compound
gauge
reading
will
be about
one
inch
lower,
numerically.
ACCESSORIES
AND
UTILITIES
Issued:
8/17/72
3G21