Help with Simrad autopilot pump

[tkeithlu]

Is there a Simrad expert out there? I need a bit of help. Here's the situation.

RPU160 pump returns "Rudder to slow" with new steering cylinder.

Double ended (balanced, two rod) cylinder is 2 1/2 by 1 1/2 by 9 inches thrust, 45 degrees to 45 degrees. That computes to 28 cu. in. or 460 cu. cm.

Range for the RPU160 is 9.8 - 33.5 cu. in., or 160 - 550 cu. cm., so I'm at about 80% of pump capacity.

There is no air in the system, but it is long - about 45 feet each way, 3/8 inch copper, pump to cylinder. The autopilot worked well with a much smaller cylinder, which blew out, and with a moderate sized two cylinder system.

So, $230 for an 18 cu. inch cylinder, or am I missing something?

Thanks for any words of wisdom.

[tkeithlu]

I found a simrad engineer. He told me that I am near the top of that pump, but here was how to fool it's tiny little brain:

Go into "Rudder Response" and tell it that the rudder, actually set at 25 degrees, is at 45 degrees. Then it thinks that it has gone full port to full starboard in less than 15 seconds, which is the minimum response.

It worked. On to the next problem.