To factory reset a Genius Valve
- Remove one battery.
- Press and hold down the middle ('o') button.
- Re-insert the battery whilst still holding the middle button.
- The valve will perform a screen test and show all the icons.
- Keep the button pressed until the screen goes blank.
The Valve is now in a factory reset default state, to add it back onto the system again see this link.
Here is a link to a help page which gives trouble shooting advice about the Genius Valve in general.