A standard RO System has a hydraulic on/off pressure valve which is controlled by source water pressure to send pre-filtered water to the membrane to make water for storage.
When water pressure in the storage tank builds up to 90% of the incoming line pressure, the standard hydraulic on/off pressure valve shuts off the flow of water to the system, stopping treated water production. When you open the RO faucet, system pressure drops as treated water exits the tank. The standard hydraulic on/off pressure valve turns on when the tank pressure is less than the source water pressure and treated water is produced through the RO system. The cycle repeats itself.
