To factory reset a Wireless Radiator Valve requires taking it off the radiator and taking it back to the Genius Hub.
To factory reset a Radiator Valve
- Remove a battery
- Press and hold down the middle ('o') button
- Re-insert the battery
- The valve will perform a screen test
- 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 radiator valve in general.