The Arduino thermostat/circulator controller has now been tested and works, I bought an Adafruit DS1307 RTC and am now displaying the time on a 20x4LCD display. The relay board has been hooked up and now turns the circulator on or off according the time and temperature. The circulator pumps hot water from the boiler through the second coil in the solar thermal storage tank to supplement any heat that may be required due to an inadequate solar collection day. While the electronics now work nicely, the next step will be do put all the components in a neat case so that the project can be finished and mounted. Let me know if you would like a copy of the code or have any questions.