PIPER
SENECA
II
SERVICE
MANUAL
b.
Connect the manifold gauge set to the airplane service values. (Refer to Figure 14-28.)
c.
The high and low manifold hand valves should be in the closed position. (Refer
to
Figures
14-25
and 14-26.)
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 14-105.
NOTE
The system should be charged
as
soon
as
it
has been evacuated.
14-105.
CHARGING
THE
SYSTEM. When the system
is
completely evacuated in accordance with
instructions given in Paragraph.14-104,one
of
the following procedures should be used
to
charge the system.
14-106.
WITH
A CHARGING STAND. This
is
the preferred method
of
charging the system.
NOTE
The following instructions apply
to
Kent Moore, 123500 charging
stand. Refer
to
Figure 14-29.
a.
With the system discharged and evacuated, proceed to hook-up the charging stand. (Refer to
Figure 14-30.)
b. Fill the charging cylinder by opening the valve at the base
of
the charging cylinder and filling the
sight glass with two pounds
of
liquid refrigerant.
c.
As
refrigerant stops filling the sight glass, open the valve
at
the top
of
the gauge neck assembly
intermittently
to
relieve head pressure and allow refrigerant
to
continue filling the sight
glass
to the
required amount.
d. When refrigerant reaches the required level in the sight glass, close both the
valve
at
the base
of
the cylinder and the valve at the
bottom
of
refrigerant tank.
Be
sure the top valve
is
fully closed.
Reissued: 10/11/79
ACCESSORIES
AND
UTILITIES
3D10
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