One thing you could potentially do is place a secondary ball valve infront of the feed to the lines, and do a dump that way with your pump changing the res for you. I'll have to get ahold of an editor to be able to show exactly what I mean. I know in stink's layout you have a ball valve behind the pump connection so as to fill the res, but what if you also placed one infront of the pump connection and just closed the one feeding to the lines (the new ball valve) and opened the one to fill the res with the garden hose or whatever type you are using, and then turning the pump on and since the line in is closed it would have to find the path of least resistance, and then it would just purge itself for you? Just an idea, hope it is helpful.