Set Appliance State:

CH temperature control to max
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Place a demand for heating and allow the boiler to heat for a few min.
Using temperature probes for the FGA (Flue Gas Analyser) measure the temperature on the primary flow and return pipes under the boiler, there should be a differential of approx. 10-15°C between the flow and return.