No problems with my water exchange Dos, but my Dos I'm using for my actual dosing is giving me problems. I just got it. I read through everything on here, but still no luck. Left side (my part A) primed no problem. Right side (my part B) runs when I press the manual priming button, but will not suck up any part B. I have changed the hose, gotten any kinks out, made sure my connections are tight. Nothin'.

Edit: I figured it out. The insert going into the DDR came out too far and was sucking from my part B. I super glued it in place.