Set Appliance State:

Mains Power Off
DHW temperature selector to 0 position
CH temperature selector to 0 position
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Reset lockout as necessary.
Allow appliance to return to standby mode.
All heating controls calling.
CH temperature selector to maximum position.
Does the appliance ignite and start to heat without kettling?