Piper PA-32R-301T SARATOGA S, Maintenance Manual

Page: 169 / 956

COOLING (cont.)
M. Charging The System (cont.)
(1) Charging stand method (cont.)
— NOTE —
If bubbling occurs in sight glass, reopen cylinder base valve
momentarily to equalize drum and cylinder pressure.
(e) Connect the heating element plug to a 110 volt outlet.
(6) Turn cylinder sight glass to match pressure reading on cylinder pressure gauge, this scale
should be used during entire charging operation.
(7) Close valve 1 (low pressure control), fully open valve 4 (refrigerant control) and allow all the
liquid refrigerant contained in the charging cylinder to enter high side of aircraft system.
(8) When the full charge of refrigerant has entered the system, close valve 4 (refrigerant control)
and valve 2 (high pressure control).
(9) After completion of charging, close all valves on the charging stand. Disconnect the high and
low pressure charging lines from the aircraft system. (A small amount of refrigerant remain-
ing in the lines will escape.) Replace lines on holder of charging stand to keep air and dirt out
of lines. Open the valve at the top of cylinder to relieve any remaining pressure, then close
the valve.
(10) Reinstall protective caps of Schrader valves and any access panels previously removed.
(2) Using the airplane compressor to charge system
This method is least desirable due to requirement of operating airplane’s engine to run compressor.
— CAUTION —
Ensure area around airplane is clean and a qualified person is
at the controls of the airplane.
(a) With system evacuated, connect refrigerant charging hose to manifold and purge the charging
hose of air. (Refer to Figure 9)
(b) Place refrigerant container on a scale to observe amount of refrigerant entering system. Open
high pressure valve and add as much refrigerant as possible.
(c) Close high pressure valve. Start engine and operate it at 900 to 1000 rpm.
(d) Operate air conditioner and set controls to maximum cooling.
(e) Open low pressure valve and complete charging system.
(f) Close low pressure valve after two pounds of refrigerant has been added to the system.
(g) While system is operating, observe the sight glass in top of receiver-dehydrator by removing
plastic plug.
(h) Sight glass should be clear of any bubbles or foam. If bubbles or foam are seen passing
through sight glass, it is an indication of a low refrigerant charge in the system and more
refrigerant is required. Make check with OAT of 70 F or higher and with air conditioner
operating.
PIPER AIRCRAFT
PA-32R-301/301T
MAINTENANCE MANUAL
21-50-00
Page 21-28
Reissued: July 1, 1993
1I11