An Arduino-based RO/DI water generator.

This revision only consists of:

• Float Switches (3)
• Dual-Relay board (1)
• 12V solenoids (2)

Each solenoid MUST have a flyback diode installed. Otherwise, the High-High sensor is tripped when the relays are powered off.

Only two relays are mandatory for RO/DI unit operation. The other relays in the code are not currently attached, but for future use.

My RO/DI unit has two manual valves.

• "Main" supply valve
• "Flush" valve

Startup operation of the RO/DI Unit requires a specific sequence:

1. Ensure the "Flush" valve is open.
2. Open "Main" supply valve.
3. After flushing the RO filter for 60 seconds, Close the "Flush" valve.

Likewise, on Shutdown:

1. Open the "Flush" valve.
2. After 60 seconds, close the "Main" supply valve.
3. Ensure the "Flush" valve is left open while system is off.