I've winterized my FunFinderX 130 for several years now, but I still don't think I'm doing it properly. Specifically: 1) how do I drain my water heater? Usually I close the valves creating a bypass and then add antifreeze to the rest of the system. I cannot see or find any kind of a drain plug. 2) My freshwater tank doesn't drain even when valve open. And 3) last time I used my water heater I got brown warm water out of it. Does that mean it has gone bad or could be sludge from not draining it last year? Thanks for any help. Also, can I leave water heater switch on all the time/safety shut off, or just turn out when I need hot water and then turn off afterwards?