Simran RPU80 instruction manual Steering wheel is turning while pump unit is operated

Simrad Reversible Pump RPU80/160/300

7.4The rudder does not stay in off-midship position, but drifts towards midship due to water pressure on the rudder

Probable reason (Does not apply for the previous model of

RPU80):

1.The non-return valves are leaking. Shut the stop cocks to the pump unit, and operate the steering gear by means of the steering wheel pump. If the steering is normal by hand operation, the fault must be in the non-return valves or the slide.

If the slide is locked because of oil contamination, the non- return valve may be held open.

If the fault is not found on the slide, both of the non-return valves have to be disassembled. Check the ball seat in the valve housing for wear etc. Replace the O-ring and copper gaskets. After having assembled the ball, spring, gasket and plug, check that the spring pressure on the ball is sufficient to keep the ball seated. The spring needs a certain pre- loading to bring the slide back to neutral position.

2.If the problem appears on an RPU80 installation, the reason may be oil contamination or worn ball seals in the suction valves. Remove the steel balls for inspection and check the seals for possible wear. Refer to paragraph 7.10.

3.If the steering gear does not function normally by hand with the pump unit isolated from the system, there must be a fault in the steering gear. In order to trace a fault of this nature, use the instructions given by the manufacturer of the steering gear.

7.5Steering wheel is turning while pump unit is operated

Probable reason:

1.Leaking lock valve in the wheel pump. Check as described under paragraph 7.4.2.

2.Lock valves are not fitted. Attach lock valve.

7.6The piston rod of the rudder cylinder does not move smoothly.

Probable reason:

1.Air in the steering system. Repeat bleeding procedure described under paragraph 5.1. Look for leakage.

26 20220422N

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