Over time, it is possible for some debris stuck inside the dump valve keeping it from sealing completely closed.  This is a pretty easy fix, the dump valve just needs to be disassembled and cleaned, it will just take couple of minutes:  First, remove the top nut, that will allow you to slide the electric coil off the valve unit so you don't have to cut any wires to remove it from the bike.  Next, remove 2 phillips screws and the chrome plate they hold down.  That will allow you to pull the shaft off the valve block, inside the shaft you'll find a plunger and spring.  Wipe off the rubber seal on the bottom of the plunger with your finger, along with the surface of the valve block below it that it seals against.  If possible, blow out everything with compressed air, to be sure there's no debris inside, then reassemble.  Should be clean and dry, do not oil.  Top nut should be hand tightened only, can be slightly snugged with a wrench but do not over-tighten.  

Valve should seal and function perfectly after that, if you have any issues after cleaning, contact technical support at 913-228-1978 ext 2, or email tech@dirtyworks-kc.com