SERVICE MANUAL & I.C.A. FOR THE 7000 AMPHIBIOUS FLOATS
Revision H Page 60 of 102 P/N 1004646 Doc. No. W7001-24-01
5.0 HYDRAULIC SYSTEM
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.
The pilot-line, attached to each of the piloted
check valves, prevents thermal expansion of
hydraulic fluid from activating the Up and
Down pressure switches. If the Up and/ or
Down switch were to be activated from thermal
expansion, the pump would not run when
commanded by the gear selector switch.
