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

Page: 599 / 956

CREW/PASSENGER OXYGEN SYSTEMS (Cont.)
REFILLING OXYGEN SYSTEM (Cont.)
2. If a cylinder has less than 5 psi pressure or has insufficient pressure to produce an audible hissing
sound when valve is cracked, it should be removed and/or purged, and if condition has existed for a
significant length of time, hydrostatically tested.
3. Make sure both charge valve and recharge cart fittings are clean and free of contamination.
– WARNING –
BE CERTAIN THERE IS NO OIL ON FITTINGS OR NEAR
IMMEDIATE VICINITY.
4. Attach service cart hose to recharge port. Fill system at a rate not exceeding 200 psig per minute
proceeding as follows:
a. To obtain correct filling pressure for oxygen system at various ambient temperatures, a table is
included for your convenience. Pressures given are not exact, but sufficiently accurate for practical
purposes of working pressures between 1800 and 2400 psig cylinders. Cylinder should be allowed
to cool to a stabilized temperature after filling before checking against values in Chart 3.
b. When using a recharge unit consisting of one supply cylinder, slowly open valve of supply unit
and allow oxygen to transfer.
c. When using a recharge unit consisting of two or more supply cylinders (cascade storage system),
it is recommended that following procedure be used:
(1) Before opening any valves, check pressure remaining in airplane’s oxygen cylinder. If it is
still partly charged, note pressure indicated on cylinder gauge. Then open and close each
valve on cascade storage system and determine which cylinder has lowest pressure. When
found if this cylinder has a pressure lower than oxygen cylinder in aircraft, do not attempt
using it for filling; use storage cylinder that has a pressure higher than the aircraft’s cylinder
but lower than others.
(2) Open valve on only one storage cylinder with lowest pressure. When pressure indicated on
aircraft’s oxygen gauge and charging gauge has become equal, close valve of storage cylinder;
then go to storage cylinder with next higher pressure and repeat procedure.
(3) If after using last storage cylinder aircraft’s oxygen system is still not fully charged, a full
storage cylinder should be put in place of a cylinder with lowest pressure and used in same
manner.
(4) A good deal of oxygen will remain in large cylinders used in cascade system after filling
only one of cylinders but such remaining oxygen will be at a pressure something less than
1850 psi which is not sufficient pressure to completely refill another aircraft cylinder,
although it will refill several smaller cylinders.
(5) It is not economical even on a three or four cylinder cascade system to begin recharging with
oxygen at less than 300 psi pressure in 300 cubic foot bank of cylinders. So use 300 cubic
foot cylinders down to approximately 300 psi; then return for refilling. In two cylinder
systems use to approximately 100 psi; then return for filling.
d. When pressure gauge on recharge unit or in aircraft reaches 1800 to 1850 psi, close pressure regu-
lator valve on recharge unit. Disconnect filler hose from filler valve; replace protective cap on
filler valve and close access cover. Check cylinder pressure according to Table IIVa after cylinder
temperature stabilizes.
5. After detaching service cart, cap hose and fittings to prevent contamination.
6. Perform a leak check of high pressure lines and clean off solution afterwards. If solution is not proper-
ly cleaned off, unusual corrosion may result.
PIPER AIRCRAFT
PA-32R-301/301T
MAINTENANCE MANUAL
35-10-00
Page 35-16
Reissued: July 1, 1993
3G1