Parts List
Circuit Diagrams & PCB Layouts


RO Water Controller - Overall System Design <<< Previous Next >>>

The controller switches on/off solenoid valves dependent on the state of the float switches in the reservoirs.   The controller will also open a solenoid valve for a specified period to allow water to drain off from the RO unit, prior to being pushed through the DI. The elected time is set by a rotary switch on the front of the control unit.  There will also be a check valve (one way valve) fitted between T junction and DI unit. This is to prevent emptying of the DI unit

The first solenoid valve (A) using a T junction is installed between RO unit and DI cartridge. The second (B) using a T junction controls water to the RO reservoir.  The third (C) controls water to the saltwater reservoir.   If solenoid value (A) is open then solenoid valves (B) and (C) are always closed.  Likewise if (B) or (C) are opened then (A) is always closed. 

There will be a pressure valve fitted the mains side of the RO unit, which will shut off if it detects that all the solenoids (A,B & C) are closed.

A float switch (FS1) is sited in the tanks sump, controlling the pump situated in the bottom of the RO reservoir. As the water level drops in the sump, the unit switches on the pump situated in RO reservoir and tops up the sump until the water level activates the float switch (FS1) again. 'Topping up' the sump is only allowed if water level in the RO reservoir is above the bottom float switch (FS3).

To enable the RO unit to have good run when filling the reservoirs. The controller will only allow filling of the RO reservoir when the water level reaches the bottom float switch (FS3). Filling of the reservoir is de-activated when the water level reaches the top float (FS2). There is a LED counter to record the number of times the unit fills the RO reservoir.

Filling of the Saltwater reservoir is activated by a switch on the controller and fills until the water level in the saltwater reservoir reaches float switch (FS4).



<<< Previous Next >>>