HYDRAULIC SYSTEM FAULTS : MAIN SYSTEM

a)       Air in system : - Indicated by excessive movement of steering wheels before steering gear moves, noise and vibration from pump.

Remedy : - To vent the system of air. To check level in replenishment tank and system for pressure tightness.

b)      Relief valves leaking :- Is indicated by the rudder movement too slow Rudder and gear hunts when helm is stationery.

Remedy :- To check for relief valve spring damage, valve lid o seat damage. To repair or renew as necessary.

c)       Worn pins and/or weak spring in hunting gear:- It will cause rudder and gear to
hunt when helm is stationery. Mainly occurs when helm is amidships.

Remedy :- To repair or replace defective parts.

d)  Slack pump pistons :- It will cause oil-leakage when pumping, delivering low pressure, resulting in sluggish operation.

e)  Overheating of pump :- If system is idle for extended period, i.e. no output and leaky non-return valve recirculating back to the tank.

When checking action of steering gear in still water, rudder locking valves can be used to simulate a load on the system.

TELEMOTOR SYSTEM FAULT :

a)           Air in system :- Indicated by excessive movement of wheel before receiver moves.

Remedy :- To purge system of air and to check that tank level is correct or not, to top up if necessary. If level found low, to check for leakage.

Leak test:- To turn wheel to hand-over port or starboard and lash in this position. Pressure gauge will need 28/41 bar depending on the system. The pressure may drop slightly in the first few minutes, but should stabilise if the particular side of the system is pressure tight. To repeat the test for the other side of the system.

b)           Broken Receiver Spring : Indication is transmitter does not automatically return to amidships. There is possibility of transmitter and receiver being out of step in the amidship position, as if the bypass is open. To replace spring and testing to be done.

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