Both flush kits can be used to help prolong the useful lifespan of an RO membrane.  The valves are plumbed into the waste water tube and when open, allow water to flush the RO membrane and rush past the flow restrictor uninhibited. A capillary flow restrictor (Capillary Flow Restrictors) should be installed in the upstream end of the blue tube.  Open the manual flush valve for approximately 60 seconds once a week or more often.  Ideally RO membranes should be flushed at the end of the water-making just before the system is turned off.  The manual flush valve should be closed (handle perpendicular to the tubing) for normal operation. 

The 24VAC Auto Flush Valve opens for 18 seconds every hour of run time and is compatible with either the Transformer for Aquatec 6800 or the Transformer for Aquatec 8800 (purchased separately).