I just recently replaced all the gaskets, check valves, etc in the chemical injection system in my '07 van. I had issues of chemical running full even when system was closed off. I replaced the disc's in the chemical block and all the gaskets/check valves. what i am struggling with now is that when i prime my system, instead of the air bubbles out of the chemical bottle and through to the hot water convince, it looks like everything is flowing back into the chemical bottle. I checked to make sure i have to arrows on the block in the right direction and it is. Would this be something i messed up with the check vavles? just a heads up i am sort of a newbie when it comes to the van. was given responsibility for it at work. thanks for the help!