News — drainback

You've purchased your solar water heater, and winter is coming. How do you make sure leftover/standing water doesn't freeze inside the system? This is where a drain back system comes in. Drainback systems are closed-loop, indirect, active systems. A heat-transfer fluid (HTF, usually water) contained in an unpressurized, closed loop is pumped through the collectors and is separate from the end-use water being heated through a heat exchanger. When the pump is off, the HTF drains out of the properly sloped collectors and pipe, leaving them empty and protected from freezing.  While this article will primarily focus on residential domestic...