Error messages:
Thermostat EFIT 540/550 has a built-in system that 
constantly checks the heating system, the thermostat itself 
and a possible network for any malfunctions.
If an error occurs, the display will fl ash together with a 
reading of the detected fault, which will be shown indicated 
by the weekday numbers 1 to 7: 
No:  Fault:  What to do:
 
  7  Clock is not adjusted  Set the clock
  4  The thermostat is  Let the thermostat cool 
    switched off because  for a period.
    of overheating  Then enter basic setup to 
      leave fault mode
  3 Confi gured as a   One unit must be 
    Slave, but cannot   confi gured as Master
  fi nd any Master unit
24