Master reset of Clack WS1 control valve

There are several button configurations for Clack control valves, but here is the button configuration for the Clack valve used by Aquatell:

For Master reset:

1. Press and hold the NEXT and DOWN buttons for 5 seconds, then release
2. Press and hold the UP and DOWN buttons for 5 seconds, then release
3. Screen will go blank, the internal piston will move, time of day reverts to 12:00pm
4. The control valve has now been reset to factory defaults