Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Gain access to upper PCB behind the display
Remove X31 (programmer) connector from the PCB and make safe
Ensure NO demands are present
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Does the CH symbol still flash (CH demand) with X31 connector removed?