Piper SARATOGA PA-32-301 Maintenance Manual page 132

PIPER AIRCRAFT
PA-32-301/301T
MAINTENANCE MANUAL
5. Connect the heating element plug to a 110-volt outlet.
6. Turn c hinder sight glass to match pressure reading on cylinder pressure gauge, this scale should be
used during entire charging operation.
7. Close low pressure control valve. fully open refrigerant control valve 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 refrigerant control valve and high
pressure control valve.
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 remaining 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 reclose the valve.
10. Reinstall protective caps of Schrader valves and any access panels previously removed.
AIRPLANE COMPRESSOR METHOD.
This method is the least desirable due to the requirement of operating the airplane's engine to run the
compressor.
CA UTION -
A scertain that the area around the airplane is clear and a qualified
person is at the controls of the airplane.
I. With the system evacuated as outlined in Evacuating the System, connect the refrigerant charging
hose to the manifold (refer to Figure 21-10) and purge the charging hose of air.
2. Place the refrigerant container on a scale to observe the amount of refrigerant entering the s stem.
Open the high pressure valve and add as much refrigerant as possible.
3. Close the high pressure valve. start the engine and operate it at 900 to 1000 RPM.
4. Operate the air conditioner and set controls to maximum cooling.
5. Open the low pressure valve and complete charging the system.
6. Close the low pressure valve after two pounds of refrigerant has been added to the system.
7. With the system still operating. observe the sight glass in the top of the receiver-dehydrator by
removing the plastic plug.
8. The sight glass should be clear of any bubbles or foam. If bubbles or foam are seen passing through
the sight glass. it is an indication of a low refrigerant charge in the system and more refrigerant is required. This
check should be made with OAT of 70°F or higher and with the air conditioner operating.
9. If more refrigerant must be added to the system. open the low pressure valve and increase engine
speed to 2000 RPM and observe the sight glass. After the sight glass has cleared. close the low pressure valve
and observe the pressure gauges. At 1000 RPM the gauge pressure should be 15 to 20 psi on the low side and
150 to 200 on the high side.
-NOTE-
Suspect leaks or an inaccurate scale if two pounds of refrigerant
does not fill the system.
21-57-02
Page 21-26
Revised: August 11. 1983
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