Abstract: A freeze protection system allows the working fluid contained in the communicating tubes of the solar collector to drain from both the input and output tubes of the collector when a first predetermined temperature of the working fluid is detected and to fill the collector via both the input and output tubes when a second predetermined temperature is detected. The invention includes valve mechanisms, of the spool valve variety, that communicate the working fluid to be heated to the collector and therefrom to a storage tank, a valve actuator and a sensor.

Abstract: A device for fastening down one section of a strap, cord or the like is disclosed herein. This device which is especially suitable for use in the installation of solar panels includes a base member to be fixedly attached to a given support structure, for example a roof, and a cap disengageably connected with the base member in a predetermined way. The base and cap include confronting surface segments which cooperate with one another for engaging and retaining the strap or cord section in a fixed position along a path having a plurality of bends, preferably four 90.degree. bends.

Abstract: A freeze protection system allows the working fluid contained in the communicating tubes of the solar collector to drain from both the input and output tubes of the collector when a first predetermined temperature of the working fluid is detected and to fill the collector via both the input and output tubes when a second predetermined temperature is detected. The invention includes valve mechanisms, of the spool valve variety, that communicate the working fluid to be heated to the collector and therefrom to a storage tank, a valve actuator and a sensor.