When you add any heating source that inputs varying amounts of energy, the resulting delivery temperatures will vary constantly. It is reasonable to expect your solar system to occasionally deliver sufficient energy to elevate storage tank temperatures above 120 degrees F, the current average temperature setting for standard water heaters. This can be dangerous for occupants in your home, with the potential to cause scalding injuries, but there is a solution. "A must-have item is an ASSE (American Society of Sanitary Engineering)-certified 1017/1016 thermostatic scald-guard valve at the storage tank's outlet, to protect all points of use within the potable distribution system," explains Bruce Fathers of Watts Regulator Co. Watts offers a free DVD, Danger: Scalding Lurks!, available through the company's website. In it, you'll find pertinent information regarding scalding and bacterial protection of potable hot-water systems. To request the video, visit http://www.wattsreg.com, click the Learn About link and click on the link for the DVD.