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Full Version: [LW11] different brand hydraulic ram
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I have two ACU400 with EVO sensors driving two B&G type 3 hydraulic ram assemblies. I got these because a friend in the business could give me a good price.
I've had problems with autopilot hunting while connected to the rudder reference sensor. I've followed all trouble shooting tips and have been unable to stop the hunting even with rudder damping set to "9".
Also, without the rudder sensors connected, I have been unable to perform the hard over test. I can get no more that hard over to mid point and the movement consists of steps rather than a continuous motion.
Are there compatibility issues between computer and rams? Should I replace the B&G with Raymarine units?
Dear shparrot.

Thank you for your post.

Can you send a system diagram over?

Are the 2 autopilots isolated from each other? You cannot have 2 autopilots sharing the same STng network.

Many Thanks
Louise
Thanks for your response. The two ACU's are independently power, each with their own rudder sensor and driving a separate hydraulic pump. They do however share the same the same STng network. I am attaching a diagram of the installation. The autopilot systems are completely isolated except for being connected to the same STng network. When I am next at the boat, I will disconnect one of the ACU's. Is there a way to electrically switch between two spurs? Not that big a deal if I have to physical swap them as you can't use two at once.
Dear shparrot,

The installation is absolutely fine.

What model are the B&G drive units?

What is the hard over time?

Many Thanks
Louise
They are B&G type 3 ram with a +PR-25 pump. Bought new in 2018. They are rated for a displacement of 22 to 35 metric tons. The boat's loaded displacement is 19 tons.

I appreciate the time you have spent on this and it appears that the problem is with the hydraulic part of the system, not the electronics. I've swapped evo sensors, rudder transducers and ACUs all resulting in the same symptoms. I think I've properly bled the hydraulics but am going to do it again and hope that resolves the problem.

Glad to hear the installation is appropriate.

Steve
You are welcome.
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