Solar heating system

A passive solar water heating system with an output and an input, said input connectable to a pressurized water supply comprising:

• pressurized cold water system input at a first pressure;
• a solar collector having an output end and having an input end, said input end of said solar collector connected to said system input;
• said input end of said solar collector connectable to said pressurized water supply;
• a hot water storage tank positioned below the elevation of said solar collector;
• said storage tank having a normally hot first input at the top, a normally cold second input at the bottom, and a normally hot first output at the top, and a normally cold second output at the bottom;
• a temperature control valve means interconnected between said output of said solar collector and said first input of said storage tank, said temperature control valve means for sensing the temperature adjacent said output end of said solar collector to allow only hot water to then enter said storage tank through said first input of storage tank;
• said second input of said storage tank connected to said collector and said pressurized water system input;
• a pressure reducing valve means interconnected between said second input of said storage tank and said system pressurized water input for supplying water to maintain pressure in said storage tank when water pressure in said storage tank drops below a certain second pressure lower than said first pressure;
• said first output of said storage tank connected to at least one hot water valve means for supplying hot water;
• and
• a pressure relief means having a first input and second input and an output, said first input of said pressure relief means connected to said second output of said storage tank output, said second input of said pressure relief means connected to said pressurized water system input, said pressure relief means for relieving cold water from the bottom of said storage tank through said cold second output at a rate equal to the flow from said solar collector output and into said normally hot first input to said storage tank;
• said pressure relief means for regulating pressure in said storage tank when said pressure reducing valve means and said hot water valve means are closed, said pressure relief means for regulating a third pressure slightly below that of said first pressure of said pressurized water input to insure water flow through said collector whenever said temperature control valve is open, said third pressure is greater than said second pressure.