I have the original Barker Auto Drain waste valves from 1999. The electrical function of the valves works perfectly, but the black valve leaks. I would like to change out both valves while I'm in there. My question is: Do I need to replace the entire system including the electric openers, or can I replace the valve part with a new valve (Valterra or whatever) and keep the existing electric opener. Will a new off the shelf valve work with the auto opener? I really need to have the correct parts in hand before I dive into this so I can repair it all at once.