Oxygen System Maintenance Manual; Recharge Valve Removal; Recharge Valve Installation - Piper PA-44-180 SEMINOLE Maintenance Manual

MAINTENANCE MANUAL
2. It is recommended that when working in the rear of the aircraft an appropriate tailstand be properly attached
to the tail.
3. With the immediate area clear of flammables (grease, hydraulic fluid, fuel) and oxygen system off, connect
a mask or tube to an outlet to exhaust any pressure in the system.
4. Remove the screws and loosen the clamps securing the shroud to the cylinder and regulator-control valve.
5. Remove the spring clamps securing the vent tube to the cylinder shroud and disconnect the tube.
6. Carefully separate the shroud along the high pressure lines.
7. The high pressure fitting on the regulator-control valve incorporates a valve that opens only when a line is
connected with it. With this in mind, carefully unscrew the high pressure line until the pressure decreases,
and then remove the line. Disconnect low pressure lines as well.
8. Loosen and open the clamps securing the bottle to the shelf. Carefully move the bottle in such a way that
fair access can be made to the control mechanism.
9. Disconnect the control cable. Be careful not to kink the cable.
10. Remove tank from aircraft being careful not to damage the regulator-control valve.
REMOVAL OF RECHARGE VALVE.
The recharge valve is located on the left rear side of the aircraft and is covered by its own access door. The
valve is interconnected with the gauge line as well as the regulator-control valve and is constantly under cylinder
pressure as long as the high pressure line is attached to the regulator.
The recommended service life for the recharge valve is 5 years, and the oxygen
cylinder must be hydrostatically tested every 5 years. With these circumstances in
mind it is recommended that the recharge valve be removed and replaced when the
cylinder is removed for services.
1. Due to the location of the recharge valve it is necessary to remove the oxygen cylinder. For ease of removal
it is recommended that the cylinder shelf also be removed.
2. Remove the screws that secure the recharge valve's protective shroud to the valve mounting dish. and slide
the shroud back over the high pressure line.
3. Unscrew the high pressure line fitting from the recharge valve and with somebody turning the screw from
outside the aircraft, back-up the nut to remove the valve.
INSTALLATION OF RECHARGE VALVE.
1. Insert the valve through the aperture in the mounting cup and align the bolt holes.
2. With the safety chain and information plate mounting washer aligned at one of the holes, install the
mounting bolts.
3. Apply teflon tape to male threads as explained earlier in this section.
4. Reconnect the high pressure line to the valve and torque the fitting 30 to 50 inch pounds.
5. Install the valve protective shroud.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— Note —
2J21
3 5 - 11 - 0 9
Page 35-13
Revised: May 15, 1989