Originally Posted by grumpygils
Your RO unit has to have a solonoid (sp) that shuts off the ro when it receives back pressure. So when the float switch shuts off the flow of water to the sump, back pressure builds on the RO unit and that shuts off the RO unit. When the float is down, solonoid opens and water flows free from the RO unit until float shuts off. Clear as mud? When I forst got my RO unit, LFS did not have the solonoid on it and it ran continuously. Water would not go into the sump becasue the float valve worked properly and shut off the flow , but waste water ran non stop from the RO unit. Needed solonoid at the RO system. Now it is fine. Solonoid goes in between your clean water line and RO setup. Mine is a coralife and the solonoid is about 1.5 inches by 1.5 inches.
Mc
I think I got it.... solonoid goes on water supply line BEFORE the water has a chance to reach the RO unit. That way ,like you said it doesnt dump waste water 24/7.