Sorry for the late response. I just noticed this now (does not show from the app). A PM will get my attention faster. I think you worked this out but in any case I routed a dedicated line from the unused port on the plenum by installing the catch can direct to the BOV using a 7/32" line which is about 5.5mm, just under the recommended 6mm ID line that Tial requires. The best way to test the valve is to put a vacuum pump on it and measure the pressure required to open the device. for centri's you need VERY light spring pressure. If it does not open either it is stuck or the diaphragm is torn.