Set Appliance State:

WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Check parameter 15 is set for no outdoor sensor.
Step 1:
Hold the power and both radiator buttons (fig 1) together
for 10 seconds until the display alternates Pr and 01.
       PARAMETER 15 ALREADY SET CORRECTLY
       PARAMETER 15 REQUIRED ADJUSTMENT