Set Appliance State:

Turn Hot Water Tap On
DHW Temperature selector to MAX
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow boiler to run and burner to ignite and run until
hot water is at maximum temperature (approx. 60°C)
Select from the following options:
Boiler operates up to maximum DHW temperature with no fault code
(Continue fault finding through main model)
Fault code reoccurs as boiler temperature increases
(Indicates sensor is becoming faulty as temperature increases)
Different fault code occurs