Welcome to deltatcontrols.com. This site specializes in the Heliodyne Delta-T line of solar thermal control units also known as solar differential controllers. Delta-T controllers are used primarily in residential and commercial solar water heating systems. Here you’ll be able to purchase controllers and accessories, obtain product support, and download the latest software updates for the Pro line of controllers. Products can be purchased using the navigation bar on the left. Product support and technical information can be found on the navigation bar to the right. For additional questions, please feel free to contact us.