FCR51 Series 3-Port Pressure Compensated Priority Flow Control Valve With Relief

The EX port has to be plumbed back to tank. That's not optional. When pressure on the CF port climbs above the relief setting, the relief valve opens and pushes excess flow out through EX. If that port is blocked or dead-ended, the relief has nowhere to send the flow and it won't function the way it's supposed to. Both the controlled flow from CF and the excess from EX will always add up to your total inlet flow, so routing EX to tank is just part of making the whole system work right.

Brand Hydraulics recommends a 30 micron filter for this valve.