Amerec AI Series Coolflush Automatic Drain and Flush System With Digital Run ClockThe Amerec ADI D automatic drain is the first step in creating an effective preventative maintenance program. Optional on all AI boilers, this electrically operated drain valve with Digital Run Clock allows for automatic routine boiler draining. As water is changed to steam, solids are left behind eventually interfering with the water level sensing controls and heating elements. One Amerec ADI D automatic drain system per boiler. What's Included