These tiny brushless, magnetic-drive circulators can be driven by PV modules or 12-volt batteries for closed-loop circulation in solar water heating systems, individual space heat zones and individual loop radiant floor loops. Use of several small pumps in a radiant floor system allows each loop to be controlled by a different thermostat. Model SID10 is designed to be powered by a 10-watt PV module, in open loop systems and can pump 3.3 gallons per minute at no head and ½gpm at 2.5 feet of head at 17 volts input. A 20-watt module should be used for glycol systems. It can circulate water in a well designed solar water heating system with two 4 x 10 collectors. Model SID10B is designed to be battery powered and has the same specifications at 12 volts. Dimensions: 4" x 4" x 5".