Amerec ADK 3/4" NPT Steam Generator Automatic Drain Valve for AK Series GeneratorsADK Automatic Drain Valve Kit for AK Series generators. Automatically drains and flushes tank after each steam bath. Order one (1) ADK drain for each generator when ordering ganged systems. The ADK automatic drain valve, automatically drains the steam generator tank by gravity, following each steam bath and flushes water through the tank to reduce sediment build up and provide longer element life. The tank remains empty until the next steam bath, when