These tiny brushless, magnetic-drive circulators can be driven by PV modules or 12 VDC batteries for closed-loop circulation in solar water heating systems and individual loops of radiant floor heating systems. Using several small pumps in a radiant floor system allows each loop to be controlled by a different thermostat. Model 10PV-12 is designed to be powered by a 10 to 20 W PV module in an open loop system and can pump 3.3 gpm at no head, and ½ gpm at 2.5' of head, at 17 VDC input. A 20 W 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 10B-12 is designed to be battery powered and has the same specifications at 12 VDC. 10B-24 is designed to operate on a 24 VDC battery system. For all three models, dimensions are 4" x 4" x 5" , they have a 30,000-hour life expectancy, and a 1-year warranty.