Dave, Hayden is right. In the past someone posted a link to one or more hydraulics web sites that went into great detail, but I don't remember where or when.
In addition to the valves being open centered, as Hayden described, I think your loader valve has a Power Beyond port (probably labelled "PB"). You have an inlet from the pump, outlet back to the sump, and power beyond that allows the flow to continue through the circuit to the auxilliary valve (if you have one) and continues on to the 3-point hitch, so that (at least theoretically) you could be operating the loader valves and the 3-point simultaneously. When I added the auxilliary valve to my B2710, I used an open centered valve (a must), but am not using the Power Beyond (it's just plugged). That means if I'm using the auxilliary valve I cannot raise the 3-point simultaneously (don't need to and don't have enough hands to operate them all at the same time anyway), but if I needed to, I could run a hose from the power beyond port to where the outlet hose now goes and then I would need to run the current outlet hose from the valve to the sump.
Hope that makes sense.
