Set Appliance State:

Mains Power Off
Ensure appliance primary circuit temperature is below 40°C
Turn DHW thermostat fully clockwise
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Turning the DHW thermostat fully clockwise should activate the warmstart facility.
When the warmstart feature has been recognised "C" will appear on the display. The letter "C" will flash while the warmstart feature operates and the boiler heats up to approximately 82°C. When the warmstart has heated sufficiently the "C" will remain in the display but stop flashing.
Does the warmstart feature operate correctly as described?