This first pic is a normal setup NOT using the power beyond feature. Pressure from the cub pump travels through the smaller line back to the newly installed bypass block, then diverted out and back to the newly installed control valve. The fluid flow goes into the "IN" port and travels through the open center valve and right back out the "OUT" port back to the return side of the bypass block, which then goes into the T?C unit as unused pressure, providing the T/C isn't being used.
If you use the T/C to lift something, that pressure builds and is felt from the pump, through the small metal line, through the bypass block, out through the line, into the "IN" and throughout the valve and then "OUT" and through the line into the T?C. The pressure needed in the T/C to lift something is felt in the new valve. Soon as the T/C moves and reaches it's spot, it's T/C relief opens and all the pressure back through the system is free flowing again and just keeps circulating. The T/C holds it's rockshaft position till it's asked to move again.
If you pull or push the new control valve lever, the (now used) pressure from the pump, then goes out the "A" or "B" depending which way you move the lever. If you move the lever to have pressure on "A", the fluid on the "B" side will release and go back out the "OUT", or vise-versa moving lever the opposite.
The next pic shows a "Power Beyond" setup. The purpose for this setup is similar to the normal setup above only with added protection. Remember the T/C unit on a cub is actually an open center control valve. when you add another open center control valve to the cub, you have 2 open center control valves in series, providing you set things up the normal way members do on the cub. Pressure from the cub pump travels through the smaller line back to newly installed bypass block, then diverted out and back to the newly installed control valve. The unused fluid flow travels into the "IN" side of new valve and because its an "open center" valve it flows straight through the valve and now exits out the "Power Beyond" side. To have this feature you need to buy a control valve with the "Power Beyond" feature and the screw in fitting. You plumb the lines differently. The line attached to the "Power Beyond" fitting goes back to the bypass block return side. The "OUT" line goes to the special fitting installed in the T/C fill hole.
The reason for a "Power Beyond" setup is it makes the new valve stronger. That fitting screws into the beyond port and reaches in and eliminates internal pressure on the sidewalls of the casting while using the T/C unit. Remember, when you use the T/C to lift something, everything from the pump to the T/C unit is under pressure. The purpose for the line running from the "OUT" to the T/C fill hole is because anytime you use the new control valve, that pressure used on either the "A" or "B" ports, once you move the lever to reposition, the trapped fluid need to be released. That trapped fluid, because of the way the valve is made internally, needs to exit and it can't exit with the rest of the fluid because you installed the "Beyond" fitting which blocks off the normal routing of fluid.
VOID this next paragraph. Due to clarafication on another post, I now feel it best to play it safe and only use a control valve with "Power Beyond"
Some members use the first setup, some use the second. My feelings, most new control valves sold today are made beefy enough that the sidewall blowing out is non-existent, especially if you have a normal operating T/C unit with it's quick relief setup. Now maybe using control valves in series on other bigger equipment, the "Beyond" setup would be called for.
Rick
