SERVICE MANUAL & ICA
8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B
Revision D
Page 67 of 104
P/N 1005723 Doc. No. W8750-24-01
The following instructions pertain to the
current production dry-handle system
configuration with reversible pumps.
BASIC DESCRIPTION
A pressure of between 500 psi and 700 psi
in the “DOWN” position and 500 psi and
1200 psi in the “UP” position is maintained
in the supply line. When the pressure falls
below 500 psi in the “UP” and “DOWN”
position, the pressure switch activates the
pump solenoid, providing power to the
pump.
When the pressure reaches 700 psi in the
“DOWN” position and 1200 in the “UP”
position, the pressure switch deactivates the
solenoid and the pump motor stops. A check
valve on the output side of the pump retains
pressure in the system while the pump is off.
The pump has an interval relief valve that
directs fluid back to the un-pressurized
pump reservoirs when the line pressure
exceeds 1400 psi. The system also has an
internal relief valve to protect against
thermal expansion when line pressure
exceeds 1900 psi.
A timer circuit is included on the powerpack
that commands pump operation briefly
regardless of pressure switch position when
a new gear position is selected; this allows
the gear system to avoid potential thermal
lock caused by fluid expansion during flight
or on the ground.
“POWERPACK” PUMP ASSEMBLY, IN AFT FUSELAGE