Diverter Valve Disection

I decided to disect my diverter valve to try to get a better understanding of how it works.  It was one of my spares, so there wasn't that much risk ;-)

Here is the valve with protective caps removed.  Of the two holes facing, the top one goes to return line and bottom to steering control box.   Notice on the steering supply side the hole in cylinder.   This is in the no or low pressure position.

Here is a look of the output hole.  Notice cylinder is blocking port.  This is the position it is in for no or low pressure. 

Here is a look of the input hole.  The plunger has a hole in the center.  As pressure builds, this compresses the spring and moves with the cylinder, down the channel.

Here is a look with the pressure spring removed.

OK, how does it work?  

Under no or low pressure, the cylinder blocks any oil from going out the output port.  Oil is allowed out the steering port.

Under partial compression of the spring, the cylinder blocks any oil from going to the steering.  Oil is allowed out of the output port.

Under full compression oil is allowed to flow from both the output and the steering ports.

The valve is marked as 8 mPa, but don't know if that is when it starts to compress, or at full compression.

The return line port was never open during my simplistic tests.  It has its own plunger and I was unable to remove that bolt.  I assume it acts as a one way valve, but not sure.