Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 173 / 881

2. Method 2:
A. Remove the access panel at the rear of the cabin to gain access to the service valves.
B. Remove the protective cap on the high pressure Schrader valve fitting and connect a charging hose
with a shut-off valve arrangement to the fitting. The charging hose must have a Schrader fitting or
adapter to fit the valve.
C. Connect the other end of the charging hose to a small cylinder of refrigerant and purge the hose by
allowing a slight amount of refrigerant gas to escape from the Schrader valve fitting.
D. The cylinder of refrigerant should be placed upright in a container of warm (125° F max.) water on
a small scale.
E. Allow approximately 1/2 pound of refrigerant to enter the system by opening the valve on the
charging hose and observing the weight change on the scale.
F. Using an electronic leak detector, check all joints and repair any leaks.
G. After completion of repair of any leaks, proceed to check the system in accordance with one of the
methods outlined for any other leaks.
H. If no further repair is required on the system, it is now ready to evacuate.
DISCHARGING THE SYSTEM. (Required only if the system contains refrigerant.)
— Note —
Applies to Kent Moore J23500 or similar charging station. Refer to Figure 21-29.
1. Close all valves on charging station.
2. Connect red high pressure charging line to high pressure Schrader valve at the evaporator fitting.
3. Open valve 8 (high pressure control) on charging station one turn.
4. Hold end of blue low pressure charging line in a shop rag and slowly open valve 2 (low pressure control)
on charging station allowing refrigerant to exhaust from system into shop rag.
— CAUTION —
REFRIGERANT CAN CAUSE FREEZING OF SKIN. BE PA RT I C U L A R LY
CAREFUL NOT TO ALLOW CONTACT WITH EYES
— CAUTION —
DO NOT ALLOW REFRIGERANT TO ESCAPE TOO RAPIDLY, AS
EXCESSIVE OIL MAY BE CARRIED OUT OF SYSTEM. WHEN HISSING
S TOPS, SYSTEM IS EMPTY AND VA LVE SHOULD BE CLOSED IF NO
FURTHER WORK IS PLANNED.
EVACUATING THE SYSTEM.
— Note —
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 air and moisture which has entered it.
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
2 1 - 5 2 - 0 7
Page 21-62
Revised: May 15, 1989
1H5
PIPER AIRCRAFT