Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH Demand
Remove PCB from appliance and move jumper next to pins 6-9 from the middle and right pins (CLOCK) to the left and middle pins (NO CLOCK)
Refit PCB
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Does the appliance now respond to a demand for CH?
Note:
Return link to its original position after test is complete.