Raymarine Autohelm 100, Install Manual

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40 TYPE 100/300 Operation and Installation Handbook
Three line system
In a three line system, hydraulic fluid flows in one direction only - out of the
helm pump to the ram and then returning from the other side of the ram to
the reservoir via a common return line.
A uniflow valve block will be fitted in the system to ensure that all returned
fluid from the ram is directed back to the reservoir.
D273-2
Bleeding the system
Correct bleeding of the hydraulic system is one of the most important
steps when installing a hydraulic pump. The presence of air in the hydraulic
system will not only reduce performance of the autopilot but also the
overall operation of the steering system.
Further to the manufacturer’s instructions for bleeding the steering
system, the following procedures should be carried out to bleed the
autopilot pump.
1. Press and hold the -10 degree key : the autopilot pump will try to drive
the rudder to port.
2. Counter this rudder movement by turning the helm to starboard to
keep the rudder stationary. This will cause any air in the pump to rise
to the helm pump and exhaust into the reservoir.