I just hooked up a natural gas heater I got for free. After watching my gas meter spin significantly faster than I'm used to (yes I did expect this) I have decided to build a solar unit to help supplement. Does anyone have a good diagram or pictures of how you've done it? I would like to have the valves thermostatically controlled so I don't have to always be there if the sun goes away. Any help is appreciated and I'm trying to do this as budget friendly as possible. Thanks