Extend the life of your DI.
When you change filters or membranes you will want to flush your system.
When any reverse somosis system first comes on, the water produced is not as good as it will be in about thirty seconds.
So in an effort to extend DI cartridge life. open the DI bypass first, leave it open for thirty seconds or so and then open the pure water line, close the DI bypass and start making RODI water.
You are simply skippng the DI stage and sending the product water to drain while the DI bypass is open.
