44TYPE 100/300 Operation and Installation HandbookPlumbingIf the autopilot operated hydraulic cylinder is independent of the manualsteering system, a solenoid operated bypass valve(Z079 (12V),Z122 (24V)) should be fitted to allow the cylinder to backdrivewhen manual steering. The bypass valve should be connected to the‘bypass’ connector on the Type CR Interface Unit.The bypass valve should be mounted between the autopilot steeringcylinder ports and, under normal circumstances, be de-energised to allowthe cylinder to backdrive. When the autopilot is engaged, the valve isenergised by the Type CR Interface to allow the autopilot steering cylinderto drive the rudder.Hydraulic cylinder Bypass valveAutopilothydraulicdriveManual steering system Cable to course computer 'Bypass' connectorD766-1Note: The bypass valve voltage must be matched to the course computersupply voltage, i.e. 12V or 24V.If the steering cylinder is unbalanced (single ended), a pilot operatedpressure relief valve must be connected (as shown) to enable excess oil tobe returned to the reservoir when the cylinder ram is retracting.
