Direct Solar Pumping from a Spring

Para Español, traducción de Julio Andrade.
This solar water pumping system has been in service for over a year with zero maintenance. It supplies water from a shallow spring to our house, and is sufficient for a family of 4, plus dogs, cats and plants. Many principles of good system design were incorporated--the system has been a real time saver for our family. Previously, we filled our cistern with garden hose and a gasoline-powered pump!

System Specifications:

  • Total Vertical Lift: 45 feet
  • Total Horizontal Distance: 480 feet
  • No batteries used!
  • Power Source: one 75 watt solar panel
  • Pump: 12 volt DC Shurflo pressure pump
  • Controller: Photowatt with limit switches and LCB
  • Float switches were installed at both the spring and the house cistern. This way, if the spring runs dry or the cistern is full, the controller will shut off the pump.
  • The controller's built-in Linear Current Booster (LCB) allows the pump to start up even on cloudy days. Without an LCB (solar panel hooked directly to pump) it would take full sun to start.
  • All pipe is buried 4 feet deep. We added 2 extra runs of pipe so we can switch over if one run freezes.
  • The pump is always under forward pressure, since it is in a valley below the spring. If the pump ever runs dry (due to feed pipe rupture or float switch failure at the spring), an air bleed valve was installed at the output side of the pump. Otherwise, air bubbles will make the pump cavitate and not work. This process was required upon initial pump installation, too.
  • We added + and - lugs at the top of the "manhole" where the pump and controller are located. This way, if we are without sun for a few days, I can drive my truck down there and hook up jumper cables from the truck battery to fill the cistern.
UPDATE! Both float switches failed during February 2001. That's only 1 1/2 years of life, and the switches cost $40 each. This caused me considerable consternation--the root cellar was flooded when the cistern switch failed. The other switch up at the spring works only part of the time. NEW UPDATE 12/03/2003 -- The manufacturer of the float switches, SJE Rhombus, found these pages on the internet, and contacted us out of the blue recently. They informed us that we are using the wrong model of float switch--the controller only switches a tiny amount of current in the float switches, but the model we got is made only for high-power loads that arc across the contacts. The retailer who recommended this model to us and who we purchased them from has been bought out by another company. SJE Rhombus is sending us 2 new float switches of the proper kind, free of charge. We thank them for GREAT customer service!

System Diagram