Resetting the handset (with a LCD display)
If the handset for what ever reason has lost communication with the Control Valve, when the
handset is held like a firm handshake the green light will be permanently lit but will pulse brighter.
In addition the communication symbol 
and other symbols will be missing
from the display and it will appear as shown.
Press and hold the SET button for around 3 seconds
until you hear a second beep.
Release the SET button and PROG appears at the top left of the handset. SETUP should also be flashing
at the top right corner of the display.
When SETUP is flashing, press the SET button to enter
the menu. H24 (or 12) will now be flashing.
Press the SET button about 9 more times until the display shows CA with a flashing 0.
Use the + button to change the CA0 to CA1.
Then press the SET button once again.
The display will now show 7ESC r4 (or some other number next to the r).