UVMax Solenoid Valve Kit: VIQUA recommends the use of a solenoid valve on all monitored UV disinfection systems that are installed. The solenoid is a valve which is required to default to a desired position, referred to as fail-safe, upon loss of power or a major alarm condition (a drop in UV intensity). Therefore the water flow will stop if there is a loss in power, a lamp failure or a loss of UV dose, giving added security to your UV system. A UV system is installed to ensure the safety of your water. A solenoid valve ensures only safe water is running into the lines in your home.